Lincoln Idealarc DC 400

SVM 122-AOct. 1996

Safety Depends on You

Lincoln arc welding and cuttingequipment is designed and builtwith safety in mind. However,your overall safety can beincreased by proper installation. . . and thoughtful operation onyour part. DO NOT INSTALL,OPERATE OR REPAIR THISEQUIPMENT WITHOUT READ-ING THIS MANUAL AND THESAFETY PRECAUTIONS CON-TAINED THROUGHOUT. And,most importantly, think beforeyou act and be careful.

SERVICE MANUAL

LINCOLN ®

ELECTRICWorld’s Leader in Welding and Cutting Products Premier Manufacturer of Industrial Motors

Sales and Service through subsidiaries and Distributors Worldwide22801 St. Clair Ave. Cleveland, Ohio 44117-1199 U.S.A. Tel. (216) 481-8100

For use with machine code numbers 9847, 9848 and 9850

IDEALARC DC-400TM

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RETURN TO MAIN INDEX

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SAFETYi i

LINCOLN ®

ELECTRIC

IDEALARC DC-400

FOR ENGINEpowered equipment.

1.a. Turn the engine off before troubleshooting and maintenancework unless the maintenance work requires it to be running.

____________________________________________________1.b.Operate engines in open, well-ventilated

areas or vent the engine exhaust fumes outdoors.

____________________________________________________1.c. Do not add the fuel near an open flame weld-

ing arc or when the engine is running. Stopthe engine and allow it to cool before refuel-ing to prevent spilled fuel from vaporizing oncontact with hot engine parts and igniting. Donot spill fuel when filling tank. If fuel is spilled,wipe it up and do not start engine until fumeshave been eliminated.

____________________________________________________1.d. Keep all equipment safety guards, covers

and devices in position and in goodrepair.Keep hands, hair, clothing and toolsaway from V-belts, gears, fans and all othermoving parts when starting, operating orrepairing equipment.

____________________________________________________

1.e. In some cases it may be necessary to remove safetyguards to perform required maintenance. Removeguards only when necessary and replace them when themaintenance requiring their removal is complete.Always use the greatest care when working near movingparts.

___________________________________________________1.f. Do not put your hands near the engine fan. Do not attempt to

override the governor or idler by pushing on the throttle con-trol rods while the engine is running.

___________________________________________________1.g. To prevent accidentally starting gasoline engines while

turning the engine or welding generator during maintenancework, disconnect the spark plug wires, distributor cap ormagneto wire as appropriate.

ARC WELDING CAN BE HAZARDOUS. PROTECT YOURSELF AND OTHERS FROM POSSIBLE SERIOUS INJURY OR DEATH.KEEP CHILDREN AWAY. PACEMAKER WEARERS SHOULD CONSULT WITH THEIR DOCTOR BEFORE OPERATING.

Read and understand the following safety highlights. For additional safety information, it is strongly recommended that youpurchase a copy of “Safety in Welding & Cutting - ANSI Standard Z49.1” from the American Welding Society, P.O. Box 351040,Miami, Florida 33135 or CSA Standard W117.2-1974. A Free copy of “Arc Welding Safety” booklet E205 is available from theLincoln Electric Company, 22801 St. Clair Avenue, Cleveland, Ohio 44117-1199.

BE SURE THAT ALL INSTALLATION, OPERATION, MAINTENANCE AND REPAIR PROCEDURES AREPERFORMED ONLY BY QUALIFIED INDIVIDUALS.

WARNING

ELECTRIC AND MAGNETIC FIELDSmay be dangerous

2.a. Electric current flowing through any conductor causes localized Electric and Magnetic Fields (EMF). Welding current creates EMF fields around welding cables and welding machines

2.b. EMF fields may interfere with some pacemakers, andwelders having a pacemaker should consult their physicianbefore welding.

2.c. Exposure to EMF fields in welding may have other healtheffects which are now not known.

2.d. All welders should use the following procedures in order tominimize exposure to EMF fields from the welding circuit:

2.d.1. Route the electrode and work cables together - Securethem with tape when possible.

2.d.2. Never coil the electrode lead around your body.

2.d.3. Do not place your body between the electrode andwork cables. If the electrode cable is on your right side, the work cable should also be on your right side.

2.d.4. Connect the work cable to the workpiece as close aspossible to the area being welded.

2.d.5. Do not work next to welding power source.

1.h. To avoid scalding, do not remove theradiator pressure cap when the engine ishot.

CALIFORNIA PROPOSITION 65 WARNINGS

Diesel engine exhaust and some of its constituentsare known to the State of California to cause can-cer, birth defects, and other reproductive harm.

The engine exhaust from this product containschemicals known to the State of California to causecancer, birth defects, or other reproductive harm.

The Above For Diesel Engines The Above For Gasoline Engines

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SAFETYii ii

LINCOLN ®

ELECTRIC

IDEALARC DC-400

ARC RAYS can burn.4.a. Use a shield with the proper filter and cover

plates to protect your eyes from sparks andthe rays of the arc when welding or observingopen arc welding. Headshield and filter lensshould conform to ANSI Z87. I standards.

4.b. Use suitable clothing made from durable flame-resistantmaterial to protect your skin and that of your helpers fromthe arc rays.

4.c. Protect other nearby personnel with suitable, non-flammablescreening and/or warn them not to watch the arc nor exposethemselves to the arc rays or to hot spatter or metal.

ELECTRIC SHOCK can kill.3.a. The electrode and work (or ground) circuits

are electrically “hot” when the welder is on.Do not touch these “hot” parts with your bareskin or wet clothing. Wear dry, hole-freegloves to insulate hands.

3.b. Insulate yourself from work and ground using dry insulation.Make certain the insulation is large enough to cover your fullarea of physical contact with work and ground.

In addition to the normal safety precautions, if weldingmust be performed under electrically hazardousconditions (in damp locations or while wearing wetclothing; on metal structures such as floors, gratings orscaffolds; when in cramped positions such as sitting,kneeling or lying, if there is a high risk of unavoidable oraccidental contact with the workpiece or ground) usethe following equipment:

• Semiautomatic DC Constant Voltage (Wire) Welder.• DC Manual (Stick) Welder.• AC Welder with Reduced Voltage Control.

3.c. In semiautomatic or automatic wire welding, the electrode,electrode reel, welding head, nozzle or semiautomaticwelding gun are also electrically “hot”.

3.d. Always be sure the work cable makes a good electricalconnection with the metal being welded. The connectionshould be as close as possible to the area being welded.

3.e. Ground the work or metal to be welded to a good electrical(earth) ground.

3.f. Maintain the electrode holder, work clamp, welding cable andwelding machine in good, safe operating condition. Replacedamaged insulation.

3.g. Never dip the electrode in water for cooling.

3.h. Never simultaneously touch electrically “hot” parts ofelectrode holders connected to two welders because voltagebetween the two can be the total of the open circuit voltageof both welders.

3.i. When working above floor level, use a safety belt to protectyourself from a fall should you get a shock.

3.j. Also see Items 6.c. and 8.

FUMES AND GASEScan be dangerous.5.a. Welding may produce fumes and gases

hazardous to health. Avoid breathing thesefumes and gases.When welding, keepyour head out of the fume. Use enoughventilation and/or exhaust at the arc to keep

fumes and gases away from the breathing zone. Whenwelding with electrodes which require specialventilation such as stainless or hard facing (seeinstructions on container or MSDS) or on lead orcadmium plated steel and other metals or coatingswhich produce highly toxic fumes, keep exposure aslow as possible and below Threshold Limit Values (TLV)using local exhaust or mechanical ventilation. Inconfined spaces or in some circumstances, outdoors, arespirator may be required. Additional precautions arealso required when welding on galvanized steel.

5.b. Do not weld in locations near chlorinated hydrocarbon vaporscoming from degreasing, cleaning or spraying operations.The heat and rays of the arc can react with solvent vapors toform phosgene, a highly toxic gas, and other irritating products.

5.c. Shielding gases used for arc welding can displace air andcause injury or death. Always use enough ventilation,especially in confined areas, to insure breathing air is safe.

5.d. Read and understand the manufacturer’s instructions for thisequipment and the consumables to be used, including thematerial safety data sheet (MSDS) and follow youremployer’s safety practices. MSDS forms are available fromyour welding distributor or from the manufacturer.

5.e. Also see item 1.b.

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SAFETYiii iii

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ELECTRIC

IDEALARC DC-400

FOR ELECTRICALLYpowered equipment.

8.a. Turn off input power using the disconnectswitch at the fuse box before working onthe equipment.

8.b. Install equipment in accordance with the U.S. NationalElectrical Code, all local codes and the manufacturer’srecommendations.

8.c. Ground the equipment in accordance with the U.S. NationalElectrical Code and the manufacturer’s recommendations.

CYLINDER may explodeif damaged.7.a. Use only compressed gas cylinders

containing the correct shielding gas for theprocess used and properly operatingregulators designed for the gas and

pressure used. All hoses, fittings, etc. should be suitable forthe application and maintained in good condition.

7.b. Always keep cylinders in an upright position securelychained to an undercarriage or fixed support.

7.c. Cylinders should be located:• Away from areas where they may be struck or subjected tophysical damage.

• A safe distance from arc welding or cutting operations andany other source of heat, sparks, or flame.

7.d. Never allow the electrode, electrode holder or any otherelectrically “hot” parts to touch a cylinder.

7.e. Keep your head and face away from the cylinder valve outletwhen opening the cylinder valve.

7.f. Valve protection caps should always be in place and handtight except when the cylinder is in use or connected foruse.

7.g. Read and follow the instructions on compressed gascylinders, associated equipment, and CGA publication P-l,“Precautions for Safe Handling of Compressed Gases inCylinders,” available from the Compressed Gas Association1235 Jefferson Davis Highway, Arlington, VA 22202.

WELDING SPARKS cancause fire or explosion.6.a. Remove fire hazards from the welding area.

If this is not possible, cover them to preventthe welding sparks from starting a fire.Remember that welding sparks and hot

materials from welding can easily go through small cracksand openings to adjacent areas. Avoid welding nearhydraulic lines. Have a fire extinguisher readily available.

6.b. Where compressed gases are to be used at the job site,special precautions should be used to prevent hazardoussituations. Refer to “Safety in Welding and Cutting” (ANSIStandard Z49.1) and the operating information for theequipment being used.

6.c. When not welding, make certain no part of the electrodecircuit is touching the work or ground. Accidental contact cancause overheating and create a fire hazard.

6.d. Do not heat, cut or weld tanks, drums or containers until theproper steps have been taken to insure that such procedureswill not cause flammable or toxic vapors from substancesinside. They can cause an explosion even though they havebeen “cleaned”. For information, purchase “RecommendedSafe Practices for the Preparation for Welding and Cutting ofContainers and Piping That Have Held HazardousSubstances”, AWS F4.1 from the American Welding Society(see address above).

6.e. Vent hollow castings or containers before heating, cutting orwelding. They may explode.

6.f. Sparks and spatter are thrown from the welding arc. Wear oilfree protective garments such as leather gloves, heavy shirt,cuffless trousers, high shoes and a cap over your hair. Wearear plugs when welding out of position or in confined places.Always wear safety glasses with side shields when in awelding area.

6.g. Connect the work cable to the work as close to the weldingarea as practical. Work cables connected to the buildingframework or other locations away from the welding areaincrease the possibility of the welding current passingthrough lifting chains, crane cables or other alternate circuits.This can create fire hazards or overheat lifting chains orcables until they fail.

6.h. Also see item 1.c.

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SAFETYiv iv

LINCOLN ®

ELECTRIC

IDEALARC DC-400

PRÉCAUTIONS DE SÛRETÉPour votre propre protection lire et observer toutes les instructionset les précautions de sûreté specifiques qui parraissent dans cemanuel aussi bien que les précautions de sûreté générales suiv-antes:

Sûreté Pour Soudage A L’Arc

1. Protegez-vous contre la secousse électrique:

a. Les circuits à l’électrode et à la piéce sont sous tensionquand la machine à souder est en marche. Eviter tou-jours tout contact entre les parties sous tension et lapeau nue ou les vétements mouillés. Porter des gantssecs et sans trous pour isoler les mains.

b. Faire trés attention de bien s’isoler de la masse quandon soude dans des endroits humides, ou sur un planch-er metallique ou des grilles metalliques, principalementdans les positions assis ou couché pour lesquelles unegrande partie du corps peut être en contact avec lamasse.

c. Maintenir le porte-électrode, la pince de masse, le câblede soudage et la machine à souder en bon et sûr étatdefonctionnement.

d. Ne jamais plonger le porte-électrode dans l’eau pour lerefroidir.

e. Ne jamais toucher simultanément les parties sous ten-sion des porte-électrodes connectés à deux machines àsouder parce que la tension entre les deux pinces peutêtre le total de la tension à vide des deux machines.

2. Dans le cas de travail au dessus du niveau du sol, se protégercontre les chutes dans le cas ou on recoit un choc. Ne jamaisenroule le câble-électrode autour de n’importe quelle partiedu corps.

3. Un coup d’arc peut être plus sévère qu’un coup de soliel,donc:

a. Utiliser un bon masque avec un verre filtrant appropriéainsi qu’un verre blanc afin de se protéger les yeux durayonnement de l’arc et des projections quand on soudeou quand on regarde l’arc.

b. Porter des vêtements convenables afin de protéger lapeau de soudeur et des aides contre le rayonnementdel’arc.

c. Protéger l’autre personnel travaillant à proximité ausoudage à l’aide d’écrans appropriés et non-inflamma-bles.

4. Des gouttes de laiter en fusion sont émises de l’arc desoudage. Se protéger avec es vêtements de protection libresde l’huile, tels que les gants en cuir, chemise épaisse, pan-talons sans revers, et chaussures montantes.

5. Toujours porter des lunettes de sécurité dans la zone desoudage. Utiliser des lunettes avec écrans lateraux dans leszones où l’on pique le laitier.

6. Eloigner les matériaux inflammables ou les recouvrir afin deprévenir ttout risque d’incendie dû étincelles.

7. Quand on ne soude pas, poser la pince à une endroit isoléde la masse. Un court-circuit accidental peut provoquer unéchauffement et un risque d’incendie.

8. S’assurer que la masse est connectée le plus prés possiblede la zone de travail qu’il est pratique de la faire. Si on placela masse sur la charpente de la construction ou d’autresendroits éloignés de la zone de travail, on augmente lerisque de voir passer le courant de soudage par les chainesde levage, câbles de grue, ou atres circuits. Cela peutprovoquer des risques d’incendie ou d’echauffement deschaines et des câbles jusqu’à ce qu’ils se rompent.

9. Assurer une ventilation suffisante dans la zone de soudage.Ceci est particuliérement important pour le soudage de tôlesgalvanisées plombées, ou cadmiées ou tout autre métal quiproduit des fumées toxiques.

10. Ne pas souder en présence de vapeurs de chlore provenantd’opéerations de dégraissage, nettoyage ou pistolage. Lachaleur ou les rayons de l’arc peuvent réagir avec lesvapeurs du solvant pour produire du phosgéne (gas forte-ment roxique) ou autres produits irritants.

PRÉCAUTIONS DE SÛRETÉ POUR LESMACHINES À SOUDER À TRANSFOR-MATEUR ET À REDRESSEUR1. Relier à la terre le chassis du poste conformement au code

de l’électricité et aux recommendations du fabricant. Le dis-positif de montage ou la piece à souder doit être branché àune bonne mise à la terre.

2. Autant que possible, l’installation et l’entretien du posteseront effectués par un électricien qualifié.

3. Avant de faires des travaux à l’interieur de poste, ladebrancher à l’interrupteur à la boite de fusibles.

4. Garder tous les couvercles et dispostifis de sûreté à leurplace.

MASTER TABLE OF CONTENTS FOR ALL SECTIONSv v

LINCOLN ®

ELECTRIC

IDEALARC DC-400

Page

Safety.................................................................................................................................................i-iv

Installation .............................................................................................................................Section A

Installation Section Table of Contents ........................................................................................A-1

Technical Specifications .............................................................................................................A-2

Safety Precautions......................................................................................................................A-3

Select Suitable Location (Stacking, Tilting, Lifting) ....................................................................A-3

Input Connections.......................................................................................................................A-4

Reconnect Procedure .................................................................................................................A-6

Output Connections....................................................................................................................A-7

Operation...............................................................................................................................Section B

Safety Instructions ......................................................................................................................B-2

General Description ....................................................................................................................B-3

Controls and Settings .................................................................................................................B-4

Welding Operation ......................................................................................................................B-6

Overload Protection....................................................................................................................B-9

Auxiliary Power ...........................................................................................................................B-9

Accessories...........................................................................................................................Section C

Maintenance .........................................................................................................................Section D

Safety Precautions......................................................................................................................D-2

Routine and Periodic Maintenance ............................................................................................D-2

General Component Locations...................................................................................................D-3

Theory of Operation .............................................................................................................Section E

Troubleshooting and Repair.................................................................................................Section F

How To Use Troubleshooting Guide ...........................................................................................F-2

Troubleshooting Guide ................................................................................................................F-4

Test Procedures ........................................................................................................................F-15

Oscilloscope Waveforms ..........................................................................................................F-33

Replacement Procedures..........................................................................................................F-40

Retest After Repair....................................................................................................................F-61

Electrical Diagrams ..............................................................................................................Section G

Parts Manual.................................................................................................................................P-234

RETURN TO MAIN INDEX

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TABLE OF CONTENTS- INSTALLATION SECTION -

Section A-1 Section A-1

LINCOLN ®

ELECTRIC

IDEALARC DC-400

Installation

Technical Specifications Idealarc DC-400 ..................................................................................A-2

Input and Output Specifications ..........................................................................................A-2

Cable and Fuse Sizes...........................................................................................................A-2

Physical Dimensions ............................................................................................................A-2

Safety Precautions......................................................................................................................A-3

Select Suitable Location.............................................................................................................A-3

Lifting .................................................................................................................................A-3

Tilting .................................................................................................................................A-3

Stacking................................................................................................................................A-3

Input Connections.......................................................................................................................A-4

Ground Connection ..............................................................................................................A-4

Input Supply Connections....................................................................................................A-4

Input Wire and Fuse Size ...............................................................................................A-5

Reconnect Procedure .................................................................................................................A-6

Output Connections....................................................................................................................A-7

Wire Feeder Connections.....................................................................................................A-8

Connections for Stick, TIG, Air/carbon Arc Operations.......................................................A-8

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INSTALLATIONA-2 A-2

LINCOLN ®

ELECTRIC

IDEALARC DC-400

TECHNICAL SPECIFICATIONS - IDEALARC DC-400

INPUT - THREE PHASE ONLY

Standard Voltage Input Current @ Rated Output

208V 87A230V 78A460V 39A575V 32A

RATED OUTPUT

Duty Cycle Amps Volts at Rated Amps

100% 400 3660% 450 3850% 500 40

OUTPUT

Current Maximum OpenMode Range Circuit Voltage Auxiliary Power

Constant Current 60 to 500 Amps 57 VDC 115 VAC, 10 AmpsConstant Voltage 60 to 500 Amps 45.5 VDC 42 VAC, 10 Amps

RECOMMENDED INPUT WIRE AND FUSE SIZES

Input Wire Size Ground Wire SizeInput Voltage / Fuse Input Ampere Type 75°C Type 75°C

Frequency (Super Lag) Rating on Copper Wire in Copper Groundor Breaker Size Nameplate Conduit AWG Wire in Conduit

Volts/Hz (IEC) Sizes AWG (IEC) Sizes

208/60 125 87 4 (21 mm2) 6 (13 mm2)230/60 125 78 4 (21 mm2) 6 (13 mm2)460/60 60 39 8 (8.4 mm2) 10 (5.3 mm2)

220/50/60 125 81 4 (21 mm2) 6 (13 mm2)230/50/60 125 77 4 (21 mm2) 6 (13 mm2)380/50/60 70 47 8 (8.4 mm2) 8 (8.4 mm2)400/50/60 70 44 8 (8.4 mm2) 8 (8.4 mm2)440/50/60 60 41 8 (8.4 mm2) 10 (5.3 mm2)

PHYSICAL DIMENSIONS

Height Width Depth Weight

30.75 in. 22.25 in. 32 in. 473 lbs.(781 mm) (565 mm) (813 mm) (215 kg)

Read this entire installation section before youstart installation.

SAFETY PRECAUTIONS

ELECTRIC SHOCK can kill.

• Do not touch electrically liveparts or electrodes with yourskin or wet clothing.

• Insulate yourself from the workand ground.

• Always wear dry insulating gloves.

Only qualified personnel should install, use, or ser-vice this equipment.

SELECT SUITABLE LOCATIONPlace the Idealarc DC-400 where clean, cooling air canflow freely in through the front louvers and out throughthe rear louvers. Keep dust, dirt, and other foreignmaterials that can be drawn into the machine to a min-imum. Failure to observe these precautions can leadto excessive operating temperatures and nuisanceshut-downs.

LIFTING

FALLING EQUIPMENT can causeinjury.

• Do not lift this machine using thelift bail if it is equipped with a heavyaccessory such as a trailer or a gascylinder.

• Lift only with equipment of adequate lifting capacity.

• Be sure the machine is stable when lifting.

• Do not stack more than three high.

• Do not stack the DC-400 on top of any othermachine.

The Idealarc DC-400 weighs 473 pounds (215 kilo-grams). A permanent lift bail is located at the top ofthe machine, positioned at the center of gravity for sta-ble lifting.

TILTING

Place the machine on a secure, level surface. Any sur-faces you place it on other than the ground must befirm, non-skid, and structurally sound.

STACKING

Idealarc DC-400s may be stacked three high. Thebottom machine must be on a stable, hard, level sur-face capable of supporting the weight of up to threemachines (1419 pounds/645 kilograms). Be sure thatthe two pins in the roof of the bottom machine fit intothe holes in the base of the machine above. The liftbail is positioned so that it fits without interferenceunder the base of the second machine.

INSTALLATIONA-3 A-3

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IDEALARC DC-400Ret

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WARNING

WARNING

INPUT CONNECTIONSBe sure the voltage, phase, and frequency of theinput power is as specified on the rating plate, lo-cated on the case front control panel. See FigureA.1.

Input supply line entry is through a hole in the caserear top panel. A removable door covers the inputconnection box, which contains the input contactor(CR1) and reconnect panel assembly for multiple volt-age machines. Input power is connected to the threeline terminals on the input contactor. See Figure A.2.

INSTALLATIONA-4 A-4

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FIGURE A.1 – RATING PLATE LOCATION FIGURE A.2 – REAR PANEL

GROUND CONNECTION

The frame of the welder must be grounded. An earthgrounding lead must be connected to the groundingterminal, marked on the input box floor with the sym-bol ( ).

INPUT SUPPLY CONNECTIONS

Be sure the voltage, phase, and frequency of the inputpower is as specified on the rating plate.


• Have a qualified electricianinstall and service this equip-ment.

• Turn the input power off at thefuse box before working on thisequipment.

• Do not touch electrically hotparts.

• Insulate yourself from the work and ground.


WARNING

1. RATING PLATE

1. INPUT SUPPLY LINE ENTRY HOLE2. INPUT CONTACTOR CR13. RECONNECT PANEL

Have a qualified electrician connect the input powerleads to the L1, L2, and L3 terminals of the input con-tactor. Follow all national and local electrical codes.Use a three-phase line. Refer to the connection dia-gram located on the inside cover of the access panelcover. Also see Figure A.3.

INPUT WIRE AND FUSE SIZE

Fuse the input circuit with the super lag fuses recom-mended on the Technical Specifications page or usedelay type circuit breakers. Choose an input andgrounding wire size according to local or nationalcodes; also see the Technical Specifications page.Using fuses or circuit breakers smaller than recom-mended may result in “nuisance” shut-offs fromwelder inrush currents, even if you are not welding athigh currents.

INSTALLATIONA-5 A-5

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IDEALARC DC-400Ret

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1. INPUT SUPPLY LINE2. INPUT CONTACTOR CR13. RECONNECT PANEL

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INSTALLATIONA-6 A-6

LINCOLN ®

ELECTRIC

IDEALARC DC-400

FIGURE A.4 - INPUT CONNECTION DIAGRAM FOR 208, 208/230 and 230/460 VOLTS AC, 50/60 HZ

THE LINCOLN ELECTRIC CO., CLEVELAND OHIO U.S.A.

1. TURN OFF THE INPUT POWER USING THE DISCONNECT SWITCH AT THE FUSE BOX.

CONNECTION FOR LOWEST RATING PLATE VOLTAGE, 50 OR 60 HZ.

CONNECTION FOR HIGHEST RATING PLATE VOLTAGE, 50 OR 60 HZ.

CODES.4. CONNECT TERMINAL MARKED TO GROUND PER LOCAL AND NATIONAL ELECTRIC

LEAST 600 VOLT INSULATION.2. DISCONNECT AND INSULATE THE H2 LEAD TERMINAL WITH TAPE TO PROVIDE AT

5. MOUNT THE LINKS IN THE POSITIONS SHOWN WITH THE PROVIDED HEX NUTS.

USE. SECURE THE REMAINING HEX NUTS IN PLACE. DOUBLE UP THE LINKS IN TWO OF THE POSITIONS TO SAVE THEM FOR FUTURE

5. MOUNT THE LINKS IN THE POSITIONS SHOWN WITH THE PROVIDED HEX NUTS.

M15009 3-17-95E

LINK

1. TURN OFF THE INPUT POWER USING THE DISCONNECT SWITCH AT THE FUSE BOX.

CODES.4. CONNECT TERMINAL MARKED TO GROUND PER LOCAL AND NATIONAL ELECTRIC

LEAST 600 VOLT INSULATION.2. DISCONNECT AND INSULATE THE H3 LEAD TERMINAL WITH TAPE TO PROVIDE AT

3. CONNECT L1, L2 & L3 INPUT SUPPLY LINES AND H2 TRANSFORMER LEADS TO THE INPUT SIDE OF THE CR1 CONTACTOR AS SHOWN.

3. CONNECT L1, L2 & L3 INPUT SUPPLY LINES AND H3 TRANSFORMER LEADS TO THE INPUT SIDE OF THE CR1 CONTACTOR AS SHOWN.

INPUT SUPPLY CONNECTION DIAGRAMDo not touch electrically live parts

Only qualified persons should install,use or service this equipment

removed

servicing

Do not operate with covers

Disconnect input power beforeNOTE: MACHINES ARE SHIPPED FROM FACTORY CONNECTED FOR OVER 300 VOLTS

DUAL VOLTAGE MACHINE

GND H2

INPUT

LINES

L1

H1

L2

L3{ CR1

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CONTACTOR

H3 PILOT

TRANSF.

LINK

GND H3

INPUT

LINES

L1

H1

L2

L3{ CR1

V

U

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CONTACTOR

H2 PILOT

TRANSF.

IMPORTANT: CHANGE LINK POSITIONS AND PILOT TRANSFORMER CONNECTIONS.

RECONNECT PROCEDUREMultiple input voltage welders are shipped connectedfor the highest voltage listed on the machine’s ratingplate. Before installing the welder, be sure the recon-nect panel is connected for the proper voltage.

Failure to follow these instructions can cause immedi-ate failure of components in the welder.

To reconnect a multiple voltage machine to a differentvoltage, remove input power. Follow the input con-nection diagram, located on the inside access panelcover, appropriate for your machine’s input voltage.These same connection diagrams are shown below.

For 208, 208/230 & 230/460 volts AC - see Figure A.4.

For 230/460/575 volts AC - see Figure A.5.CAUTION

OUTPUT CONNECTIONSThe output (welding) cables are connected to the outputterminals marked “+” and “-”. See Table A.1 for recom-mended cable sizes for the combined lengths of elec-trode and work cables. They are located at the lowerright and lower left corners of the front panel. Strain

relief for the cables is provided by routing them throughthe rectangular holes in the base before connectingthem to the output terminals. Lift the output terminalcover to access the output terminals. Lower the coverafter making the connections. See Figure A.6.

INSTALLATIONA-7 A-7

LINCOLN ®

ELECTRIC

IDEALARC DC-400Ret

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THE LINCOLN ELECTRIC CO., CLEVELAND OHIO U.S.A. M15666

INPUT SUPPLY CONNECTION DIAGRAM

H3GNDH2

Do not touch electrically live parts

Only qualified persons should install,use or service this equipment

removed

servicing

Do not operate with covers

Disconnect input power before

INPUT

LINES

L1

H1

L2

L3{CR1

V

U

W

CONTACTOR

H4 PILOT

TRANSF.

1. CONNECT L1, L2 & L3 INPUT SUPPLY LINES AND H1 & H4 PILOT TRANSFORMER LEADS TO THE INPUT SIDE OF CR1 CONTACTOR AS SHOWN.2. INSULATE UNUSED H2, H3 LEAD TERMINALS SEPERATELY TO PROVIDE AT LEAST 600V INSULATION.

4. CONNECT TRANSFORMER LEADS 16, 17, 18, 4 & 13, 5 & 14, 6 & 15 TO RECONNECT PANEL.5. TAPE SEPERATELY TO PROVIDE AT LEAST 600V INSULATION 1, 2, 3, 7, 8, 9. TAPE INSULATED UNUSED LEADS TOGETHER AWAY FROM LIVE METAL PARTS.

IDEALARC (230 / 460 / 575)

NOTE: MACHINES ARE SHIPPED FROM FACTORY CONNECTED FOR 575V

CONNECTION FOR 575 VOLTS, 60 HZ.

3. CONNECT TERMINAL MARKED TO SYSTEM GROUND PER NATIONAL ELECTRIC CODES.







RECONNECT

PANEL

4. CONNECT TRANSFORMER LEADS 1, 2, 3, 4 & 7, 5 & 8, 6 & 9 TO RECONNECT PANEL.5. TAPE SEPERATELY TO PROVIDE AT LEAST 600V INSULATION 13, 14, 15, 16, 17, 18. TAPE INSULATED UNUSED LEADS TOGETHER AWAY FROM LIVE METAL PARTS.

4. CONNECT TRANSFORMER LEADS 1 & 7, 2 & 8, 3 & 9, 4 & 5 & 6, TO RECONNECT PANEL.5. TAPE SEPERATELY TO PROVIDE AT LEAST 600V INSULATION 13, 14, 15, 16, 17, 18. TAPE INSULATED UNUSED LEADS TOGETHER AWAY FROM LIVE METAL PARTS.

18

17

16

6155

14413

987321

H4GNDH2

INPUT

LINES

L1

H1

L2

L3{CR1

V

U

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CONTACTOR

H3 PILOT

TRANSF.

RECONNECT

PANEL

3

2

1

695847

151413181716

H4GNDH3

INPUT

LINES

L1

H1

L2

L3{CR1

V

U

W

CONTACTOR

H2 PILOT

TRANSF.

RECONNECT

PANEL654

93

8271

151413181716

IMPORTANT: CHANGE LINK POSITIONS AND PILOT TRANSFORMER CONNECTIONS .

5-26-95

FIGURE A.6 - OUTPUT TERMINAL CONNECTIONS

1. NEGATIVE (-) WELDING CABLE CONNECTION2. POSITIVE (+) WELDING CABLE CONNECTION3. CABLE STRAIN RELIEF HOLE LOCATION

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INSTALLATIONA-8 A-8

LINCOLN ®

ELECTRIC

IDEALARC DC-400

TABLE A.1 - CABLE SIZES FOR COMBINED LENGTHS OF COPPER ELECTRODEAND WORK CABLES

Up to 50 ft 50 - 100 ft 100 - 150 ft 150 - 200 ft 200 - 250 ftMachine Size (15 m) (15 - 30 m) (30 - 46 m) (46 - 61 m) (67 - 76 m)

400 Amp 3/0 3/0 3/0 3/0 4/0(100% Duty 85 mm2 85 mm2 85 mm2 85 mm2 107 mm2

Cycle)

500 Amp 2/0 2/0 3/0 3/0 4/0(50% Duty 67 mm2 67 mm2 85 mm2 85 mm2 107 mm2

Cycle)

WIRE FEEDER CONNECTIONS

See the Accessories section of this manual for spe-cific instructions on connecting the following semi-automatic and automatic wire feeders to the Idealarc DC-400:

Automatic Wire Feeders:

• NA-3

• NA-5

Semi-automatic Wire Feeders:

• LN-7

• LN-8

• LN-9

• LN-25

• LN-742

CONNECTIONS FOR STICK, TIG, ORAIR/CARBON ARC CUTTING OPERA-TIONS

The output terminals are energized at all times whenthe Idealarc DC-400 is used for stick, TIG, or air/car-bon arc cutting.

The work and electrode cables for stick, TIG, orair/carbon arc cutting are connected as described ear-lier, under the heading Output Connections. A TIGtorch is connected to the electrode (+) terminal of thewelder. Select cable size according to Table A.1.

Do not connect a TIG torch and stick electrode cableat the same time. They will both be electrically HOT.

If the Idealarc DC-400 is already set up for wire feederoperation, all wire feeder unit control, electrode, andwork cables must be disconnected first before youcan connect the cables for stick, TIG, or air/carbon arcoperation.

However, the Idealarc DC-400 can be used for bothwire feeder operation and stick, TIG, air/carbon arcoperation if a K804-1 Multiprocess Switch is used.See the Accessories section of this manual for spe-cific instructions on connecting and using theMultiprocess Switch.

WARNING

WARNING

96OCT

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Section B-1 Section B-1

LINCOLN ®

ELECTRIC

IDEALARC DC-400

- OPERATION SECTION -Operation...............................................................................................................................Section B

Safety Instructions ......................................................................................................................B-2

General Description ....................................................................................................................B-3

Recommended Processes ...................................................................................................B-3

Operational Features and Controls ......................................................................................B-3

Design Features and Advantages ........................................................................................B-3

Welding Capability................................................................................................................B-3

Limitations ............................................................................................................................B-3

Controls and Settings ................................................................................................................B-4

Welding Operation ......................................................................................................................B-6

Operating Steps ...................................................................................................................B-6

Local Control..................................................................................................................B-6

Remote Control ..............................................................................................................B-6

Welding Procedure Recommendations .........................................................................B-6

Semiautomatic and Automatic Wire Feeding with an Idealarc DC-400 ..............................B-6

NA-3 Automatic Wire Feeder .........................................................................................B-7

Good Arc Striking Guidelines for the NA-3.............................................................B-7

Arc Striking with the NA-3 Start Board...................................................................B-7

NA-5 Automatic Wire Feeder .........................................................................................B-8

LN-8 Semiautomatic Wire Feeder..................................................................................B-8

LN-7 and LN-9 Semiautomatic Wire Feeders................................................................B-9

Overload Protection....................................................................................................................B-9

Auxiliary Power ...........................................................................................................................B-9

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B-2 B-2

LINCOLN ®

ELECTRIC

IDEALARC DC-400

OPERATING INSTRUCTIONSRead and understand this entire section of operatinginstructions before operating the machine.

SAFETY INSTRUCTIONS


• Do not touch electrically live parts orelectrodes with your skin or wet cloth-ing.

• Insulate yourself from the work and ground.


FUMES AND GASES can bedangerous.

• Keep your head out of fumes.

• Use ventilation or exhaust to removefumes from breathing zone.

WELDING SPARKS can causefire or explosion.

• Keep flammable material away.

• Do not weld on containers that have held com-bustibles.

ARC RAYS can burn.

• Wear eye, ear, and body protection.

Observe additional Safety Guidelines detailed inthe beginning of this manual.

WARNING

OPERATION

GENERAL DESCRIPTIONThe Idealarc DC-400 is an SCR controlled three-phaseinput, DC output power source for welding and cut-ting. It uses a single range potentiometer control. Thewelder’s unique combination of transformer, three-phase semiconverter rectifier, capacitor bank, arc con-trol choke, and solid state control system deliver out-standing arc characteristics in the constant voltagemode. For stick welding, an Arc Force Control enablesthe Idealarc-400 to perform much like the R3R-500.

RECOMMENDED PROCESSES

The Idealarc DC-400 is recomended for all open arcprocesses including Innershield® and all solid wire andgas procedures within its capacity of 60 to 500 amps.It also can perform stick and TIG welding and air/car-bon arc gouging up to 5/16” (8 mm) diameter. A modeswitch on the front control panel selects CV (FCAW,GMAW), CV Submerged Arc, or CC (stick/TIG).

The Idealarc DC-400 can be connected to wire feed-ing equipment, including:

• Automatic wire feeders NA-3, NA-5, and NA-5R.(Requires the DC-400 Diode Kit option to use thecold start and cold electrode sensing features ofthese feeders.)

• Semi-automatic wire feeders LN-7, LN-7 GMA, LN-8, LN-9, LN-9 GMA, LN23P, LN-25, LN-742.

• Tractors LT-56, LT-7.

OPERATIONAL FEATURES AND CONTROLS

The following operational controls are standard on theIdealarc DC-400:

• Power Source Pilot Light

• ON/OFF Power Toggle Switch

• Output Control Potentiometer

• Output Control Switch (with Local or Remote posi-tions)

• Output Terminals On or Remote Switch

• Arc Force Selector (for CC stick or TIG processesonly)

• Auxiliary Power Connections for Wire Feeder andOther Equipment (115V and 42V)

• Mode Switch

• Arc Control

• Thermal Protection Indicator Light

• DC Ammeter

• DC Voltmeter

• Voltmeter “+” Electrode or “-” Electrode Switch

DESIGN FEATURES AND ADVANTAGES

• Input line voltage compensation keeps output con-stant for fluctuations of ± 10%.

• SCR control extends life of mechanical contactors.

• Hinged front control panel provides easy access toprinted circuit boards and other control circuitry.

• Fully enclosed fan motor with permanently lubri-cated, sealed ball bearings needs no maintenance.

• Fully recessed control panel protects controls andminimizes accidental contact.

• Recessed output terminals and hinged terminalcover reduce chance of accidental contact.

• Low profile case permits installation under a work-bench.

• Removable rear access panel provides easy accessto input contactor and input lead connections.

• Removable case sides provide easy access for ser-vice or inspection, even when machines are stacked.

• Dripproof enclosure design permits outdoor operation.

• Double-dipped transformer, SCR bridge, and chokeresist corrosion.

WELDING CAPABILITY

The Idealarc DC-400 has the following duty cycleratings. If the duty cycle is exceeded, a thermal pro-tector will shut off the machine output until it cools tonormal operating temperature. The amber thermalprotection indicator light will turn on until the machinecools.

Duty Cycle* Amps Volts100% 400 3660% 450 3850% 500 40

*Based on a 10 minute time period. For example, a 60% duty cyclemeans 6 minutes on and 4 minutes off.

LIMITATIONS

The Idealarc DC-400 has no provisions for paralleling.

OPERATIONB-3 B-3

LINCOLN ®

ELECTRIC

IDEALARC DC-400

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CONTROLS AND SETTINGSAll operator controls and settings are located on thecase front assembly. See Figure B.1 for their loca-tions.

FIGURE B.1 – CASE FRONT CONTROLS

1. POWER SOURCE PILOT LIGHT: This light indi-cates that the power source input contactor isenergized (closed). This also means that the mainpower transformer and all auxiliary control trans-formers are energized.

2. ON/OFF POWER TOGGLE SWITCH: Energizesor de-engergizes the input contactor which is pow-ered by the 115 volt auxiliary transformer. Theswitch turns the machine ON or OFF. Position “I”is ON; position “0” is OFF.

3. OUTPUT CONTROL POTENTIOMETER: Con-trols voltage in CV mode and current in CC mode.

4. OUTPUT CONTROL SWITCH (WITH LOCAL ORREMOTE POSITIONS): Selects the mode of con-trol. In the “Local” position, control is by themachine control panel. In the “Remote” position,control is by either a wire feeder unit or through anoptional remote control device.

5. OUTPUT TERMINALS “ON” OR “REMOTE”SWITCH: When in the “Remote” position, leads#2 and #4 have to be jumpered externally to ener-gize the output terminals. When in the “ON” posi-tion, this switch internally jumpers leads #2 and #4,which energizes the output terminals.

6. ARC FORCE SELECTOR: Allows you to selectthe ideal arc force according to the procedure andelectrode being used for CC stick or TIG welding.It controls the amount of current added to thewelding current when the electrode shorts to thework. At minimum setting, no extra short circuitcurrent is added. The arc will be softer and haveless spatter but may be more prone to sticking. Atmaximum setting, the arc will be more forceful andless prone to sticking but will produce more spat-ter.

OPERATIONB-4 B-4

LINCOLN ®

ELECTRIC

IDEALARC DC-400Ret

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1. Power Source Pilot Light2. ON/OFF Power Toggle Switch3. Output Control Potentiometer4. Output Control Switch (with Local or Remote positions)5. Output Terminals Switch (with On or Remote positions)6. Arc Force Selector (for CC stick or TIG processes only)7. Auxiliary Power Connections for Wire Feeder and Other

Equipment (115V and 42V)

8. Mode Switch9. Arc Control

10. Thermal Protection Indicator Light11. DC Ammeter12. DC Voltmeter13. Voltmeter “+” Electrode or “-” Electrode Switch

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OPERATIONB-5 B-5

LINCOLN ®

ELECTRIC

IDEALARC DC-400

7. AUXILIARY POWER AND REMOTE CONTROLCONNECTIONS FOR WIRE FEEDER ANDOTHER EQUIPMENT (115V AND 42V): The 14-pin amphenol receptacle provides either 115 or42 volts AC as well as remote control connec-tions. Terminal strips with screw connections arelocated behind the hinged control panel for hardwired control. Only 115 volts AC is available onthe terminal strip. A strain relief connector is pro-vided for cable entry.

8. MODE SWITCH: Selects between ConstantVoltage FCAW/GMAW and Constant VoltageSubmerged Arc (Red range on dial), and ConstantCurrent Stick/TIG (Blue range on dial).

9. ARC CONTROL: A five-position switch thatchanges the pinch effect of the arc when in the CVFCAW/GMAW mode. It allows control of spatter,fluidity, and bead shape. The Arc Control is set toprovide optimum welding depending on theprocess, position, and electrode. Pinch effect isincreased by turning the control clockwise. It canalso be adjusted while the machine is in opera-tion.

10. THERMAL PROTECTION INDICATOR LIGHT:This amber light indicates that either of the twoprotective thermostats has opened. Outputpower is removed, but input power is still beingapplied to the machine.

11. DC AMMETER: Displays output current whenwelding.

12. DC VOLTMETER: Displays output voltage whenwelding.

13. VOLTMETER “+” ELECTRODE OR “-” ELEC-TRODE SWITCH: Selects the electrode polarityfor the remote work sensing lead (#21) when usingautomatic or semiautomatic wire feeders.

WELDING OPERATION

OPERATING STEPS

LOCAL CONTROL

The following procedures are for using the IdealarcDC-400 in the local control mode of operation. Forremote control of the machine, see the REMOTECONTROL section.

Before operating the machine, make sure you have allmaterials needed to complete the job. Be sure you arefamiliar with and have taken all possible safety pre-cautions before starting work. It is important that youfollow these operating steps each time you use themachine.

1. Turn on the main AC input power to the machine.

2. Set the VOLTMETER “+” or “-” switch to theappropriate position.

• Set toggle to “´Electrode Negative” position ifthe electrode is connected to the negative (-)output terminal.

• Set toggle to “Electrode Positive” position if theelectrode is connected to the positive (+) outputterminal.

3. Set the welding MODE switch to welding processbeing used.

• CV FCAW/GMAW

• CV Submerged Arc

• CC Stick/Tig

4. Set the OUTPUT CONTROL switch to “Local.”(Exception: when using an LN-9, LN-9 GMA, orNA-5 wire feeder, set the switch to “Remote.”Otherwise, the wire feeder may automatically shutdown.

5. Set the OUTPUT TERMINALS switch to thedesired mode.

6. Set the ARC FORCE CONTROL to midrange, 5-6.This control is for CC stick or TIG welding only.Adjust for best characteristics as necessary.

7. Set the ARC CONTROL to midrange, 3. This con-trol is for CV FCAW/GMAW welding only. Adjustas necessary for best pinch control.

8. Set the ON/OFF POWER toggle switch to the ONposition (1).

• The power source pilot light glows.

• The fan starts.

9. Set OUTPUT CONTROL potentiometer to desiredvoltage or current.

10. Make the weld.

REMOTE CONTROL

The toggle switch on the control panel labeled “OutputControl Remote” gives you the option of controllingthe machine output from a remote location. In the“Remote” position a wire feeder with remote controlcapabilities or a remote control device such as a K775must be connected to the DC-400. Refer to theAccessories section for wire feeder installation infor-mation.

WELDING PROCEDURE RECOMMENDATIONS

Select Mode Switch position based on type of weldingto be done.

1. FCAW/GMAW Welding/Other Open Arc Processes:Use the CV FCAW/GMAW mode.

2. Submerged Arc Welding: Use the CV SubmergedArc mode. If performing high speed welding,switch between the CV Submerged Arc and the CVFCAW/GMAW mode and use the mode that pro-duces the best welding results.

3. Air/Carbon Arc Cutting / Stick Welding / HighCurrent, Large Puddle Submerged Arc Welding:Use the CC mode. When the Idealarc DC-400 isused for Air/Carbon Arc cutting, the OUTPUTCONTROL potentiometer should be set to “9” ini-tially. Based on the size of the carbon being usedor the process, turn the potentiometer to a lowersetting as required by the process. You can usecarbon rods up to 5/16” (8 mm) in diameter at cur-rents as high as 450 amps with excellent arc con-trol. The welder protection circuit protects themachine from extremely high short circuitingpulses.

SEMIAUTOMATIC AND AUTOMATIC WIREFEEDING WITH AN IDEALARC DC-400

When using the Idealarc DC-400 with semiautomaticor automatic wire feeding equipment and for stickwelding or air/carbon arc cutting, it is recommendedthat the optional MULTIPROCESS switch be used.This switch permits you to easily change the polarity ofthe connected wire feeding equipment or switch tostick welding or air/carbon arc cutting.

OPERATIONB-6 B-6

LINCOLN ®

ELECTRIC

IDEALARC DC-400Ret

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NA-3 AUTOMATIC WIRE FEEDER

1. Set the DC-400 OUTPUT CONTROL switch to“Remote.”

NOTE: Later model NA-3 automatic wire feedersare capable of cold starts when the NA-3Mode switch is in the CV or CC mode posi-tion. Some earlier models are capable ofcold starting only in the CC mode position.Cold starting enables you to inch the wiredown to the work, automatically stop, andautomatically energize the flux hoppervalve. The cold start feature requires thefactory installed diode option. See theAccessories section.

2. Set the DC-400 welding MODE switch for thedesired process: CV Submerged Arc, CVFCAW/GMAW mode or CC mode.

3. Set the NA-3 mode switch position to either CV orCC to match the DC-400 mode selected in step 2.

4. Set the OUTPUT CONTROL switch to “Remote.”

5. Set the OUTPUT TERMINALS switch to “Remote.”

6. For CC welding, set the ARC FORCE CONTROL tomidrange, 5-6. After welding starts, adjust as nec-essary.

7. For CV FCAW/GMAW welding, set the ARC CON-TROL to midrange, 3. After welding starts, adjustas necessary.

8. Refer to the NA-3 operator’s manual for instructionson how to use the NA-3 in conjunction with the DC-400.

9. Follow the guidelines for good arc striking detailedbelow for each welding mode.

GOOD ARC STRIKING GUIDELINES FOR THE NA-3 WITH THE IDEALARC DC-400 IN THE CVFCAW/GMAW, CV SUBMERGED ARC ORSTICK/TIG CC WELDING MODES.

Following are some basic arc striking techniques thatapply to all wire feed processes. Using these proce-dures should provide trouble-free starting. These pro-cedures apply to single, solid wires and Innershieldwires.

1. Cut the electrode to a sharp point.

2. Set the NA-3 Open Circuit Voltage Control to thesame dial setting as the Arc Voltage Control. If thisis a new welding procedure, a good starting point isto set the Open Circuit Voltage Control to #6.

NOTE: The open circuit voltage of the IdealarcDC-400 varies from apporximately 12volts to 45 volts in the CV FCAW/GMAWor CV Submerged Arc modes. The opencircuit voltage is constant in the CC mode.

3. Run a test weld. Set proper current, voltage, andtravel speed.

a. For the best starting performance, the NA-3Open Circuit Voltage Control and VoltageControl setting should be the same. Set theInch Speed Control for the slowest inch speedpossible.

b. To adjust the Open Circuit Voltage Control toget the best starting performance, makerepeated starts observing the NA-3 voltmeter.

When the voltmeter pointer swings smoothly up tothe desired arc voltage, without undershooting orovershooting the desired arc voltage, the OpenCircuit Voltage Control is set properly.

If the voltmeter pointer overshoots the desiredvoltage and then returns to the desired voltage, theOpen Circuit Voltage Control is set too high. Thiscan result in a bad start where the wire tends to“blast off.”

If the voltmeter pointer hesitates before coming upto the desired voltage, the Open Circuit VoltageControl is set too low. This can cause the elec-trode to stub.

4. Start and make the weld.

a. Cold starts. For cold starts, be sure the workpiece is clean and the electrode makes posi-tive contact with the work piece.

b. Hot “On the Fly” starts. For hot starts, travelshould begin before the wire contacts the workpiece.

ARC STRIKING WITH THE NA-3 START BOARD

When electrical stickouts exceed 1-3/4” (44.4 mm) anNA-3 Start Board may be required to improve arc strik-ing.

When the NA-3 Start Board is used to improve arcstriking, use the following procedures:

1. Set start time at 0.

2. Set NA-3 start current and start voltage at mid-range.

3. Set the NA-3 output current and voltage to theproper settings for the welding procedure to beused.

OPERATIONB-7 B-7

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ELECTRIC

IDEALARC DC-400Ret

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4. Turn the Start Board Timer to maximum.

5. Set Start Board current and voltage control.

a. Set the Start Board current control to 1-1/2dial numbers below that set on the NA-3 cur-rent control.

b. Set the Start Board voltage control equal withthe NA-3 voltage control setting.

NOTE: These Start Board current and voltage set-tings result in a start up current that islower than the NA-3 current setting andapproximately equal with the NA-3 voltagesetting for the desired welding procedure.

6. Establish the correct arc striking procedure withthe NA-3 Start Board timer set at maximum.

a. For the best starting performance, the NA-3Open Circuit Voltage Control and VoltageControl setting should be the same. Set theInch Speed Control for the slowest inch speedpossible.

b. To adjust the Open Circuit Voltage Control toget the best starting performance, makerepeated starts observing the NA-3 voltmeter.

When the voltmeter pointer swings smoothly up tothe desired arc voltage, without undershooting orovershooting the desired arc voltage, the OpenCircuit Voltage Control is set properly.

If the voltmeter pointer overshoots the desiredvoltage and then returns to the desired voltage,the Open Circuit Voltage Control is set too high.This can result in a bad start where the wire tendsto “blast off.”

If the voltmeter pointer hesitates before coming upto the desired voltage, the Open Circuit VoltageControl is set too low. This can cause the elec-trode to stub.

c. Set NA-3 Start Board current and voltage asclose to the welding procedure current andvoltage as possible.

NOTE: The Start Board current and voltageshould be as close as possible to thewelding procedure current and voltage,while still getting satisfactory starts.

d. Set the start time to as low a time as possiblewhile still getting satisfactory starts.

7. Start and make the weld.

NA-5 AUTOMATIVE WIRE FEEDER

When using the Idealarc DC-400 with the NA-5 wirefeeder, set the controls on the Idealarc DC-400 as fol-lows for the best performance:

1. Turn OFF main AC input power to the Idealarc DC-400.

2. Connect the electrode cables to the terminalpolarity to be used.

3. Set the VOLTMETER “+” or “-” switch to the samepolarity as the electrode cable connection.

4. Set the OUTPUT CONTROL switch to “Remote.”


6. Set the Idealarc DC-400 welding MODE switch tothe position that matches the welding processbeing used.

a. For submerged arc welding, set weldingMODE SWITCH TO CV SUBMERGED ARCposition.

b. For all open arc welding processes, set weld-ing MODE switch TO CV FCAW/GMAW posi-tion.

7. Set the ARC CONTROL to midrange, 3. Afterwelding starts, adjust as necessary.

LN-8 SEMIAUTOMATIC WIRE FEEDER

To use the LN-8 Semiautomatic Wire Feeder with theIdealarc DC-400:

1. Set the Idealarc DC-400 welding MODE switch toeither CV FCAW/GMAW mode or CV SubmergedArc mode, depending on the welding processbeing used.

2. Set the Idealarc DC-400 OUTPUT CONTROLswitch to “Remote.”


4. Set the ARC CONTROL to midrange, 3.

5. Set the LN-8 Welding Mode switch to the CV posi-tion. The LN-8 Welding Mode switch is located onthe variable voltage (CC) board.

6. Refer to the LN-8 Operator’s Manual for instruc-tions on how to use the LN-8.

OPERATIONB-8 B-8

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OPERATIONB-9 B-9

LINCOLN ®

ELECTRIC

IDEALARC DC-400

LN-7 AND LN-9 SEMIAUTOMATIC WIRE FEEDERSOR OTHER CONSTANT SPEED WIRE FEEDERS

To use the LN-7, LN-9, or other constant wire feedspeed semiautomatic wire feeders with the IdealarcDC-400:

1. Set the Idealarc DC-400 welding MODE switch toeither CV FCAW/GMAW mode or CV SubmergedArc mode, depending on the welding processbeing used.

NOTE: These semiautomatic wire feeders cannotbe used in the CC mode.

2. Set the Idealarc DC-400 OUTPUT CONTROLswitch.

a. LN-7: Use either an optional K775 RemoteControl Box Assembly or set the Idealarc DC-400 OUTPUT CONTROL switch in the “Local”position.

b. LN-9: Refer to the LN-9 Operator’s Manual forinstructions on how to use the LN-9.

c. LN-25: Refer to the LN-25 Operator’s Manualfor instructions on how to use the LN-25.

d. LN-742: Refer to the LN-742 Operator’sManual for instructions on how to use the LN-742.

OVERLOAD PROTECTIONThe power source is thermostatically protected withproximity thermostats against overloads or insufficientcooling. One thermostat is located on the nose of thecenter bottom primary coil. A second thermostat isattached to the lead connecting the secondaries. If themachine is overloaded, the primary thermostat opens,the output becomes zero, and the amber thermal pro-tection light comes on. The fan will continue to run.The secondary thermostat opens with either an exces-sive overload or insufficient cooling. The outputbecomes zero, and the amber thermal protection lightcomes on. When the machine cools, the thermostatsreset, and the thermal protection light goes off.

The power source is also protected against overloadson the SCR bridge asssembly through an electronicprotection circuit. This circuit senses an overload onthe power source and limits the output to 550 amps byphasing back the SCRs.

The Idealarc DC-400 also has self-restoring fusing toprevent damage to the machine in the event of anaccidental grounding of the remote control leads (#75,#76 or #77).

AUXILIARY POWERThe Idealarc DC-400 can provide nominally 115 voltAC and 42 volt AC auxiliary power for operating wirefeeding equipment and other accessories. This poweris available at the 14-pin amphenol on the controlpanel and/or at the terminal strip behind the hingedcontrol panel on the case front. On the amphenol, 115volts AC is available at pins A and J (Domestic andExport models only); 42 volts AC is available at pins Iand K. On the terminal strip, 115 volts AC is availableat terminals 31 and 32; 42 volts AC is not available.The two circuits, 115 volts AC and 42 volts AC, are iso-lated; and each is protected by a 10 amp circuit break-er.

On European and export models, a ContinentalEuropean receptacle is provided on the rear panel forsupplying 220 volts AC to a water cooler. A 2 amp cir-cuit breaker, also located on the rear panel, protectsthis circuit from overloads or short circuits.

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OC TABLE OF CONTENTS

- ACCESSORIES -

Accessories...........................................................................................................................Section C

Options/Accessories...................................................................................................................C-2

Factory Installed Option.......................................................................................................C-2

Field Installed Options .........................................................................................................C-2

Cover for 14-Pin Amphenol ...........................................................................................C-2

Multiprocess Switch (K804-1)........................................................................................C-2

Remote Output Adapter Cable (K857)...........................................................................C-4

Remote Control Adapter Cable (K864) ..........................................................................C-4

Amptrol Adapter Cable (K843) .......................................................................................C-4

Capacitor Discharge Circuit (K828-1) ............................................................................C-6

Hi-Freq Kit (K799) ..........................................................................................................C-6

Amptrol Adapter for K799 (K915) ..................................................................................C-6

Undercarriages (K817, K817R, K841) ............................................................................C-6

Connection of Lincoln Electric Automatic or Semiautomatic Wire Feeders ..............................C-6

Automatic Wire Feeders.......................................................................................................C-6

NA-3 (Terminal Strip) ......................................................................................................C-6

NA-5 (Terminal Strip) ......................................................................................................C-7

NA-3 or NA-5 (14-Pin Amphenol) ..................................................................................C-8

Semiautomatic Wire Feeders ...............................................................................................C-9

LN-7 (14-Pin Amphenol) ................................................................................................C-9

LN-7 (Terminal Strip) ....................................................................................................C-10

LN-8 or LN-9 (Terminal Strip).......................................................................................C-11

LN-8 or LN-9 (14-Pin Amphenol) .................................................................................C-12

LN-742 (14-Pin Amphenol) ..........................................................................................C-13

Section C-1 Section C-1

LINCOLN ®

ELECTRIC

IDEALARC DC-400

OPTIONS/ACCESSORIES

FACTORY INSTALLED OPTION

DIODE OPTION

This factory installed option allows use of the cold-start and cold electrode sensing features of the NA-3,NA-5, or NA-5R automatic wire feeders. See the topic,Connecting the NA-3 [NA-5] to the Idealarc DC-400in this section of the manual.

FIELD INSTALLED OPTIONS

The following options/accessories are available foryour Idealarc DC-400 from your local LincolnDistributor.

COVER FOR 14-PIN AMPHENOL (LINCOLNELECTRIC PART NUMBER S17062-3)

Protects the amphenol from dirt and moisture whenthe amphenol is not being used.

MULTIPROCESS SWITCH (K804-1. ALSOAVAILABLE AS A FACTORY INSTALLED OPTION.)

Required when using the DC-400 for both automat-ic/semiautomatic and stick/air carbon arc. This field orfactory installed kit mounts on the front of the DC-400.It includes hinged covers over its output studs.

The switch has three positions.

• Wire Feeder Positive

• Wire Feeder Negative

• Stick/Air Carbon Arc

The Multiprocess Switch gives you the ability to:

• Switch between “Stick Welding/Air-Carbon ArcCutting” or “Positive Wire Feeder” or “Negative WireFeeder.”

• Change the polarity of a semi-automatic or auto-matic wire feeder without changing any electricalcable connections. See Figure C.1.

The Multiprocess Switch has two sets of output termi-nals. You connect the wire feeder unit cables to theset of terminals on the left side of the box (facing thefront of the machine) and the stick or air/carbon arccables to the set of terminals on the right side asshown in Figure C.1.

When the Multiprocess Switch is in the “Stick Welding/Air-Carbon Arc” position, only those terminals areenergized. The wire feeder nozzle or gun and elec-trode are not electrically “hot” when in this mode.

Refer to installation instructions (M17137) includedwith Multiprocess Kit for installation.

ACCESSORIESC-2 C-2

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FIGURE C.1MULTIPROCESS SWITCH

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ACCESSORIESC-3 C-3

LINCOLN ®

ELECTRIC

IDEALARC DC-400

Multiprocess Switch Operation

The operation of the Multiprocess Switch is as follows:

A semiautomatic or automatic wire feed unit electrodeand work cables are connected to the terminals on theleft side of the box. Stick or air carbon arc electrodeand work cables are connected to the terminals on theswitch. With the switch in the left position, the wirefeed terminals are electrode negative. In the centerposition, the wire feeder terminals are electrode posi-tive. In both the left and center switch position, theright side stick terminals are disconnected. In the rightswitch position, the wire feed terminals are discon-nected from the DC-400 and the stick terminals con-nected. The polarity of the stick terminals is markedon the end of the box. To change polarity, the elec-trode and work cables must be interchanged. In thestick position, the stick terminals are energized at alltimes.

Connections

(For those applications where it is not necessary tohave separate work cables for stick and semiautomat-ic welding.)

If both stick and semiautomatic welding is done on thesame workpiece, only one work cable is required. Todo this, connect a 4/0 (107 mm2) jumper from the workterminal on the semiautomatic side to the terminal tobe used for work on the stick side. The work cablefrom the semiautomatic side then serves as the workcable for both semiautomatic and stick welding. SeeFigure C.2.

To change stick polarity, reverse the leads at the (+)and (-) terminals on the right side of the MultiprocessSwitch.

NOTE: When a DC-400 equipped with MultiprocessSwitch is mounted on an undercarriage, theundercarriage handle in the resting positioncan hit the case of the Multiprocess Switch.This does no harm, but if the user desires, a1/4” or 3/8” bolt and nut may be placed in thehole in the undercarriage tow bar to limit thetravel of the undercarriage handle.

FIGURE C.2 – SINGLE WORK CABLE WITH JUMPER

To stick electrode holder orair carbon arc torch

User supplied 4/0 (107 mm2)jumper

To semi-auto or auto equipment

REMOTE OUTPUT CONTROL (K857 WITH K864ADAPTER PLUG OR K775)

The K857 has a 6-pin MS-style connector. The K857requires a K864 adapter cable which connects to the14-pin connector on the machine.

An optional “remote output control” is available. Thisis the same remote control that is used on the LincolnR3R and DC-600 power sources (K775). The K775consists of a control box with 28 ft (8.5m) of four con-ductor cable. This connects to terminals 75, 76, and77 on the terminal strip and the case grounding screwmarked with the symbol on the machine. Theseterminals are located behind the control panel on thefront. This device will give the same control as the out-put control on the machine.

REMOTE CONTROL ADAPTER CABLE (K864)

A “V” cable 12 inches (.30 m) long to connect a K857Remote Control, K812 Hand Amptrol or K870 FootAmptrol (6-pin connector) with a wire-feeder (14-pinconnector) and the machine (14-pin connector). If aremote control or amptrol is used alone, the wire-feed-er connection is not used. See Figure C.3.

AMPTROL™ ADAPTER CABLE (K843)

A five wire cable, 12 inches (.30 m) long, is available foreasy connection of standard K812 Hand Amptrol orK870 Foot Amptrol. The cable has a 6-pin MS-styleconnector which connects to the Amptrol, and termi-nals which connect to 75, 76 and 77 on the machineterminal strip and to the case grounding screw. TheAmptrol will control the same range of output as thecurrent control on the welder. (If a smaller range ofcontrol is desired for finer adjustment, a K775 Remotemay be used in conjunction with the Amptrol AdapterCable Kit. Connection information is included with theAmptrol Adapter Cable Kit.) The Amptrol arc startswitch does not function in this application.

K843 AMPTROL™ ADAPTER INSTALLATIONINSTRUCTIONS


• Turn the input supply power OFFbefore installing plugs or cables orwhen connecting or disconnectingplugs to the welder.

This K843 adapter is used to connect Amptrol (K812,K813 or K870), remote control (K775), and Hi-Freq™(K799) accessories to the DC-400. The OUTPUTCONTROL switch must be in “Remote” for Amptrol™to control current. Accessories may be combined andconnected in four different ways, as shown on the fol-lowing page.

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FIGURE C.3 – REMOTE CONTROL ADAPTER CABLE (K864)

STRAIGHT PLUG (14 PIN)TO POWER SOURCE

CABLE RECEPTACLE (6 SOCKET)TO: 1) K857 REMOTE CONTROL

2) K812 HAND AMPTROL3) K870 FOOT AMPTROL

CABLE RECEPTACLE (14 SOCKET)TO: L-7 WIRE FEEDER

WARNING

ACCESSORIESC-5 C-5

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Amptrol Only: The Amptrol provides remote currentcontrol through the full range of the power source.

Amptrol Plus Remote Limit Control: The Amptrolprovides remote current control from the minimum ofthe power source to a maximum set by the remotelimit control.

Amptrol and Hi-Freq. Kit: The Amptrol will start theHi-Freq kit to turn on gas and high frequency startingfor DC TIG welding. The Amptrol controls currentthrough the full range of the power source.

Amptrol and Hi-Freq. Kit Plus Remote LimitControl: The Amptrolswitch will start the Hi-Freq kit toturn on gas and high frequency starting for DC TIGwelding. The Amptrol controls current from the mini-mum of the power source to a maximum set by theremote limit control.

K812, K813 orK870 Amptrol

Power sourceterminal

strip

K843Adapter

Black and white leadsnot used. Tapeand insulate.

K812, K813or K870Amptrol

K843 AdapterArc start cable(included with

K799)

K799Hi-Freq Kit

K812, K813or K870Amptrol

K775 RemoteLimit Control

K843 AdapterArc start cable(included with K799)

K799Hi-FreqKit

CUT OFFARC STARTSWITCH andconnect blacklead to black andwhite lead to white.

K812, K813 orK870 Amptrol

K843Adapter

Black and whiteleads not used. Tape and insulate.

Bolt and nutconnection.

Insulateand tape.

Bolt and nutconnection.

Insulateand tape.

CUT OFFARC STARTSWITCH and connect blacklead to black and whitelead to white.

K843 AMPTROL ADAPTER INSTALLATION INSTRUCTIONS (Continued)

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Mounts inside the DC-400. Recommended when:

• DC-400 is used in conjunction with any LN-23P orolder LN-8 or LN-9 semiautomatic wire-feeder.Eliminates possible arc flash re-start of weld whentrigger interlock is used. Not required with currentLN-8 (above Code 8700), or LN-9s with serial num-bers above 115187 (manufactured after 12/83), orany LN-9 having an L6043-1 Power PC Board.

• DC-400 is used with an LN-22 equipped with anolder K279 Contactor-Voltage Control Option.Eliminates electrode overrun when gun trigger isreleased. Not required when later K279 (aboveCode 8800) is used.

• DC-400 is used with any semiautomatic wire-feederand possible small spark is objectionable if elec-trode touches work just after gun trigger is released.

Install per M17060 instructions included with the kit.

HI-FREQ™ KIT (K799 FOR CODES 8634 ANDABOVE ONLY)

Kit supplies the high frequency plus gas valve for DCTIG welding. The DC-400 is shipped with proper R.F.bypass circuitry installed to protect the control circuitwhen welding with a HI-FREQ unit. K844 Water ValveOption Kit can be used with K799 when TIG weldingwith water cooled torches.

AMPTROL ADAPTER FOR K799 HI-FREQ KIT(K915. REQUIRES K864 ADAPTER OR K843ADAPTER)

A “V” cable to connect a K799 Hi-Freq kit (5-pin con-nector) with either a K812 Hand Amptrol or a K870Foot Amptrol (6-pin connector) and the machine. Thecable going to the machine has a 6-pin connectorwhich requires either a K864 adapter to connect withthe 14-pin connector on the machine or a K843adapter to connect to terminals #75, #76, #77 and thecase grounding screw on the machine.

UNDERCARRIAGES (K817, K817R, K841)

For easy moving of the machine, optional undercar-riages are available with either steel (K817) or rubbertired (K817R) wheels or a platform undercarriage(K841) with mountings for two gas cylinders at the rearof the welder.

Installation instructions are included with each kit.

CONNECTION OF LINCOLN ELECTRICAUTOMATIC OR SEMIAUTOMATIC WIREFEEDERS


• Only qualified personnel shouldperform this maintenance.

• Turn the input power OFF at the dis-connect switch or fuse box before working on thisequipment.

• Do not touch electrically hot parts.

Auxiliary power for wire feeder operation is available atboth a 14-pin amphenol and at terminal strips withscrew-type connections located behind the hingedcontrol panel on the front of the machine. The 14-pinamphenol can provide both 115 VAC (pins A and J)and 40-42 VAC (pins I and K). The terminal strip pro-vides 115 VAC only (terminals 31 and 32). The two cir-cuits are isolated, and each is protected by a 10A cir-cuit breaker.

The following descriptions show how to connect thewire feeders using either the 14-pin amphenol or theterminal strip.

NOTE: The LN-742 wire feeder, because it operateson 42 VAC, can be connected only to the 14-pin amphenol.

AUTOMATIC WIRE FEEDERS

CONNECTING THE NA-3 TO THE IDEALARC DC-400 (TERMINAL STRIP)

1. Disconnect main AC input power to the IdealarcDC-400.

2. Set Idealarc DC-400 POWER toggle switch to theOFF (0) position.

3. Connect the wire feeder control cable leads to theIdealarc DC-400 terminal strip as shown in FigureC.4.

Connect the wire feeder control cable ground leadto the frame terminal marked .

NOTE: The Idealarc DC-400 must be properlygrounded.

WARNING

FIGURE C.4 – NA-3 WIRE FEEDERCONNECTION TO THE IDEALARC DC-400

5. Extend wire feeder control cable lead #21 so it canbe connected directly to the work piece.

a. Make a bolted connection using AWG #14 orlarger insulated wire. Tape the bolted connec-tion with insulating tape.

b. An S-16586- X remote voltage sensing worklead is available for this purpose.

c. Keep the #21 lead electrically separate fromthe work cable circuit and connection.

d. Tape the #21 lead to work cable for ease ofuse.

NOTE: The connection diagram shown in Figure C.4shows the electrode connected for positivepolarity. To change polarity:

a. Set the Idealarc DC-400 POWER toggleswitch to the OFF (0) position.

b. Move the electrode cable to the negative (-)output terminal.

c. Move the work cable to the positive (+) outputterminal.

d. Set the VOLTMETER toggle switch to nega-tive (-).

6. Set the DC-400 OUTPUT CONTROL switch to the“Remote” position and the OUTPUT TERMINALSswitch in the “Remote” position.

CONNECTING THE NA-5 TO THEIDEALARC DC-400 (TERMINAL STRIP)


2. Set the Idealarc DC-400 POWER toggle switch tothe OFF (0) position.


FIGURE C.5 – NA-5 WIRE FEEDERCONNECTION TO THE IDEALARC DC-400

NOTE: If using a K215 control cable, connectcontrol cable leads #75, #76, and #77 tothe matching #75, #76, and #77 terminalson the terminal strip of the Idealarc DC-400.

4. Connect the wire feeder control cable ground leadto the frame terminal marked .


ACCESSORIESC-7 C-7

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6. Connect NA-5 wire feeder control jumpers onVoltage Control Board. See NA-5 Operator’sManual.





d. Set the VOLTMETER toggle switch to negative(-).

NOTE: For proper NA-5 operation, the electrodecables must be secured under the clamp baron the left side of the NA-5 Control Box.

7. Set the DC-400 OUTPUT CONTROL switch to the“Remote” position and the OUTPUT TERMINALSswitch to the “Remote” position.

CONNECTING THE NA-3 OR NA-5 TO THE IDEALARC DC-400 (14-PIN AMPHENOL)


2. Set the Idealarc DC-400 POWER switch to the OFF(0) position.

3. Connect the electrode cable from the K597-XXInput Cable Assembly to the “+” terminal of thewelder and to the wire feeder. Connect the workcable to the “-” terminal of the welder. Reverse thishookup for negative polarity. See Figure C.6.

NOTE: Welding cable must be sized for the cur-rent and duty cycle of the application.

4. Set the welder VOLTMETER switch to the desiredpolarity, either DC (-) or DC (+).

5. Set the MODE switch to a CV (constant voltage)position.

6. Set the DC-400 OUTPUT CONTROL switch to the“Remote” position and the OUTPUT TERMINALSswitch to the “Remote” position.

ACCESSORIESC-8 C-8

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IDEALARC DC-400Ret

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FIGURE C.6IDEALARC DC-400/NA-3/NA-5 14-PIN AMPHENOL CONNECTION

TO NA-3 or NA-5 INPUTCABLE PLUG

K597-XX INPUT CABLE ASSEMBLY

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ACCESSORIESC-9 C-9

LINCOLN ®

ELECTRIC

IDEALARC DC-400

FIGURE C.7IDEALARC DC-400/LN-7 WITH K584 INPUT CABLE ASSEMBLY CONNECTION DIAGRAM

SEMIAUTOMATIC WIRE FEEDERS

CONNECTING THE LN-7 TO THE IDEALARC DC-400 (14-PIN AMPHENOL)


2. Set the POWER toggle switch to the OFF (0) posi-tion.

3. Connect the electrode cable from the K584-XXInput Cable Assembly to the “+” terminal of thewelder and to the LN-7 wire feeder. Connect thework cable to the “-” terminal of the welder.Reverse this hookup for negative polarity.

NOTE: Welding cable must be sized for the currentand duty cycle of the application.

4. Connect K584-XX Input Cable between the DC-400 and the LN-7. See Figure C.7.

5. Set the welder VOLTMETER toggle switch to thedesired polarity, either DC (-) or DC (+).

6. Set the MODE switch to a CV (constant voltage)position at the welder.

7. Adjust wire feed speed at the LN-7 and set thewelding voltage with the OUTPUT CONTROL.

NOTE: If optional remote control is used, place theOUTPUT CONTROL and the OUTPUT TERMI-NALS switch in the “Remote” position.

CONNECTING THE LN-7 TO THEIDEALARC DC-400 (TERMINAL STRIP)






5. PERFORM THIS STEP ONLY IF THE LN-7 ISEQUIPPED WITH A METER KIT.

Extend wire feeder control cable lead #21 so it canbe connected directly to the work piece.


NOTE: If the work cable length is less than 25 feetand the connections to the work piece aresecure, then wire feeder control cable lead#21 can be connected directly to the DC-400 terminal strip.




NOTE: The connection diagram shown in FigureC.8 shows the electrode connected forpositive polarity. To change polarity:

a. Set the IDEALARC DC-400 POWER toggleswitch to the OFF (0) position.



d. Set the VOLTMETER toggle switch to nega-tive (-).

ACCESSORIESC-10 C-10

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ELECTRIC

IDEALARC DC-400Ret

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FIGURE C.8 - LN-7 WIRE FEEDER CONNECTION TO THE IDEALARC DC-400

CONNECTING THE LN-8 OR LN-9 TO THEIDEALARC DC-400 (TERMINAL STRIP)










NOTE: Using the extended #21 lead eliminatesthe need to use the LN-9’s remote worklead accessory, which has a direct worklead jack.

6. Connect LN-9 wire feeder control jumpers onVoltage Control board. See LN-9 Operator’sManual.





d. Set the VOLTMETER toggle switch to negative(-).

7. Set the OUTPUT CONTROL switch to the“Remote” position and the OUTPUT TERMINALSswitch to the “Remote” position.


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IDEALARC DC-400Ret

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OC FIGURE C.9 - LN-8 OR LN-9 WIRE FEEDER CONNECTION TO THE IDEALARC DC-400

CONNECTING THE LN-8 OR LN-9 TO THEIDEALARC DC-400 (14-PIN AMPHENOL)



3. Connect the electrode cable from the LN-8 or LN-9 to the “+” terminal of the welder. Connectthe work cable to the “-” terminal of the welder.Reverse this hookup for negative polarity. SeeFigure C.10.


4. Connect the input cable (K595-XX) between the14-pin amphenol on the DC-400 and the inputcable plug on the LN-8 or LN-9. See Figure C.10.



7. Adjust wire feed speed at the LN-8 or LN-9 andset the welding voltage with the WIRE FEEDERVOLTAGE CONTROL.

Place the OUTPUT CONTROL switch in the “Remote”position and the OUTPUT TERMINALS switch in the“Remote” position.


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IDEALARC DC-400Ret

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FIGURE C.10 – IDEALARC DC-400/LN-8 OR LN-9 WITH K595-XX CABLE

TO LN8/LN9 INPUTCABLE PLUG

K595-XX INPUT CABLE ASSEMBLY

CONNECTING THE LN-742 TO THE IDEALARC DC-400 (14-PIN AMPHENOL)



3. Connect the electrode cable from the LN-742 tothe “+” terminal of the welder. Connect the workcable to the “-” terminal of the welder. Reversethis hookup for negative polarity. See Figure C.11.


4. Connect the K592 Control Cable to the 14-pinamphenol on the IDEALARC DC-400 and to theinput cable plug on the LN-742. See Figure C.11.



7. Adjust wire feed speed at the LN-742 and set thewelding voltage with the output ARC CONTROL toa CV (constant voltage) position at the welder.

NOTE: If optional remote control is used, set theOUTPUT CONTROL switch to the “Remote”position and the OUTPUT TERMINALS switchto the “Remote” position.


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FIGURE C.11 – IDEALARC DC-400/LN-742 CONNECTION DIAGRAM

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Section D-1 Section D-1

LINCOLN ®

ELECTRIC

IDEALARC DC-400

TABLE OF CONTENTS-MAINTENANCE-

Maintenance .........................................................................................................................Section D

Safety Precautions......................................................................................................................D-2

Routine and Periodic Maintenance ............................................................................................D-2

General Component Locations...................................................................................................D-3

SAFETY PRECAUTIONS


• Only qualified personnelshould perform this mainte-nance.

• Turn the input power OFF atthe disconnect switch or fusebox before working on thisequipment.

• Do not touch electrically hot parts.

ROUTINE AND PERIODIC MAINTENANCEPerform the following preventative maintenance atleast once every six months.

Perform the following daily:

1. Check that no combustible materials are aroundthe machine or in the welding or cutting area.

2. Remove any debris, dust, dirt, or materials thatcould block cooling air flow to the machine.

3. Inspect the electrode cables for any slits or punc-tures in the cable jacket. Also check for any othercondition that could affect the proper operation ofthe machine.

Perform periodically:

1. In extremely dusty conditions, dirt may clog thecooling air channels, causing the machine to runhot. Blow out the machine at regular intervals withlow pressure air. Clean the following parts. SeeFigure D.1.

• Main transformer and choke

• SCR/diode bridge

• Control PC board

• Starting PC board

• Electrode and work cable connections

• Fan assembly

NOTE: The fan motor has sealed bearings that requireno service.

• Remote control terminal strip TS1.

NOTE: Keeping remote control terminal strip TS1clean is especially important in damp locations.

MAINTENANCED-2 D-2

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MAINTENANCED-3 D-3

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IDEALARC DC-400

5

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FIGURE D.1 – GENERAL COMPONENT LOCATIONS

1. CONTROL PANEL2. SCR/DIODE BRIDGE3. MAIN TRANSFORMER4. CHOKE5. RECONNECT PANEL (LOCATION)6. INPUT CONTACTOR (LOCATION)7. FAN ASSEMBLY8. CONTROL TRANSFORMER9. CAPACITORS

10. PC BOARDS (LOCATION)11. CASE FRONT12. OUPUT TERMINALS

(LOCATION BENEATH HINGED PANEL)

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Section E-1 Section E-1

LINCOLN ®

ELECTRIC

IDEALARC DC-400

Theory of Operation .............................................................................................................Section E

General Description ...............................................................................................................E-2

Input Line Voltage, Contactor and Main Transformer ...........................................................E-2

Output Mode and Control, Rectification and Feedback .......................................................E-3

Protective Devices and Circuits ............................................................................................E-4

SCR Operation.......................................................................................................................E-5

TABLE OF CONTENTS-THEORY OF OPERATION SECTION-

FAN

115VAC

42VAC

14 PINAMPHENOL

REMOTE CONTROLTO

CONTROLBOARD

CONTROL BOARD

OUTPUT CONTROL

ARC FORCECONTROL

CONTROLTRANSFORMER

POWERSWITCH

RECONNECT

INPUTCONTACTOR

TERMI

NAL

STRIP

TRANSFORMERMAIN

SCR DIODEHYBRID BRIDGE

/

PARTOF

MODESWITCH

CAPACITORS

SHUNT REEDSWITCH

STARTBOARD

PARTOF

MODESWITCH

OUTPUTCHOKE

NEGATIVEOUTPUT

TERMINAL

POSITIVEOUTPUT

TERMINAL

PART OF MODE

SWITCH

OUTPUT

GATE

SIGNALS

FEEDBACK

FEEDBACK

FIGURE E.1 – IDEALARC DC-400 BLOCK LOGIC DIAGRAM

GENERAL DESCRIPTIONThe DC-400 is a multiprocess welder power sourcecapable of both constant voltage and constant currentoperation. Its power system is SCR controlled withsolid state electronic circuitry. Minimum to maximumoutput is obtained with a single potentiometer control.

INPUT LINE VOLTAGE,CONTACTOR AND MAINTRANSFORMERThe desired three-phase input power is connected tothe DC-400 through an input contactor, located in theinput box at the rear of the machine. Two phases ofthe input line are also connected to the control trans-former, which, through the power switch, suppliespower to activate the input contactor.

A reconnect panel allows the user to configure themachine for the desired input voltage. This AC inputvoltage is applied to the primary of the main trans-former.

The transformer changes the high voltage, low currentinput power to a lower voltage, higher current output.The finishes or “neutrals” of the main secondary coilsare connected together, and the three starts of thesecondary windings are connected to the rectifierbridge assembly. In addition, the main transformer hasseparate and isolated 115VAC and 42VAC auxiliarywindings. The 115VAC winding supplies power to thecooling fan and also offers 10 amps of auxiliary power,at the terminal strip and 14 pin amphenol, to operatewire feeding equipment. The 42VAC auxiliary power isavailable at the 14 pin amphenol only and is protectedby a 10 amp circuit breaker. The three 21VAC phaseangle windings are also housed in the main trans-former assembly. These windings provide power and“timing” for the control board.

THEORY OF OPERATIONE-2 E-2

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OC FIGURE E.2 – INPUT LINE VOLTAGE, CONTACTOR AND MAIN TRANSFORMER

NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.

FAN

115VAC

42VAC

14 PINAMPHENOL

REMOTE CONTROLTO

CONTROLBOARD

CONTROL BOARD

OUTPUT CONTROL

ARC FORCECONTROL

CONTROLTRANSFORMER

POWERSWITCH

RECONNECT

INPUTCONTACTOR

TERMI

NAL

STRIP

TRANSFORMERMAIN


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MODESWITCH

CAPACITORS

SHUNT REEDSWITCH

STARTBOARD

PARTOF

MODESWITCH

OUTPUTCHOKE

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TERMINAL

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TERMINAL

PART OF MODE

SWITCH

OUTPUT

GATE

SIGNALS

FEEDBACK

FEEDBACK

OUTPUT MODE AND CONTROL,RECTIFICATION AND FEEDBACKThe three-phase AC output from the main transformersecondary is rectified and controlled through the SCR/diode bridge. Output current and voltage is sensed atthe shunt and output terminals. This feedback infor-mation is processed in the control board. The controlboard compares the commands of the Mode Switch,the Arc Force Control (constant current mode only),and the Output Control (or remote control) with thefeedback information and sends the appropriate gatefiring signals to the SCR/diode bridge.

A “dry closure” of leads #2 and #4, either at the termi-nal strip or the 14 pin amphenol, signals the controlboard to apply gate firing signals to the SCR/ DiodeBridge, which creates a DC voltage at the output of thebridge assembly. If the Mode Switch is in the constantvoltage (FCAW/GMAW) mode, this DC voltage is fil-tered by the Output Capacitors.

The heavy current carrying portion of the ModeSwitch is connected between the output choke,which stores energy and provides current filtering,and the negative output terminal. Depending uponthe mode selected, different portions of the choke areneeded. In the constant current mode (CC), theentire choke is connected into the welding output cir-cuit. When constant voltage (CV) is required, onlypart of the choke is utilized.

The starting circuit board function is to momentarilychange the inductance effect that the choke has onthe welding circuit. This is accomplished by changingthe amount of “pinch” or arc control windings that areactive in the output choke. When weld current isestablished, the reed switch closes and the start boardbecomes inactive.


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NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.

FIGURE E.3 – OUTPUT MODE AND CONTROL, RECTIFICATION AND FEEDBACK

FAN

115VAC

42VAC

14 PINAMPHENOL

REMOTE CONTROLTO

CONTROLBOARD

CONTROL BOARD

OUTPUT CONTROL

ARC FORCECONTROL

CONTROLTRANSFORMER

POWERSWITCH

RECONNECT

INPUTCONTACTOR

TERMI

NAL

STRIP

TRANSFORMERMAIN


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CAPACITORS

SHUNT REEDSWITCH

STARTBOARD

PARTOF

MODESWITCH

OUTPUTCHOKE

NEGATIVEOUTPUT

TERMINAL

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TERMINAL

PART OF MODE

SWITCH

OUTPUT

GATE

SIGNALS

FEEDBACK

FEEDBACK

PROTECTIVE DEVICES ANDCIRCUITSTwo thermostats protect the DC-400 from excessiveoperating temperatures and overload conditions.Excessive operating temperatures may be caused byinsufficient cooling air or by operating the machinebeyond the duty cycle and output rating. The primarythermostat, located on the nose of the bottom centerprimary coil, will activate if the machine is overloaded.The machine will not have output, the amber thermalprotection light will glow, and the fan will continue torun.

The secondary thermostat, located on the lead con-necting the secondary coils together, will open eitherwith an excessive overload or insufficient cooling. Themachine will not have output, the amber protectionlight will be on, and the fan should continue to oper-ate. When the thermostats reset, the amber protec-tion light will be off.

Upon restart, if the fan does not turn or the air intakelouvers are obstructed, the input power must beremoved and the fan problem or air obstruction cor-rected.

The DC-400 is also protected against overloads on theSCR/diode bridge assembly through an electronicprotection circuit located on the control board. Thiscircuit senses an overload on the power source andlimits the output to 550 amps by phasing back theSCRs.

A circuit is also provided to protect the circuitry fromaccidental grounds. If the external remote controlleads (#75, #76 or #77) are accidentally connected tothe positive output welding lead, the DC-400 outputwill be reduced to a low level, thus preventing damageto the machine. If an erroneous connection is madebetween the remote control leads and the negativeoutput welding lead, the control board self-restoringfuses will blow, preventing damage to the machine.


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SCR OPERATIONA silicon controlled rectifier (SCR) is a three terminaldevice used to control rather large currents to a load.An SCR acts very much like a switch. When a gatesignal is applied to the SCR, it is turned ON and thereis current flow from anode to cathode. In the ONstate, the SCR acts like a closed switch. When theSCR is turned OFF, there is no current flow from anodeto cathode; thus the device acts like an open switch.As the name suggests, the SCR is a rectifier; so itpasses current only during positive half cycles of theAC supply. The positive half cycle is the portion of thesine wave in which the anode of the SCR is more pos-itive than the cathode.

When an AC supply voltage is applied to the SCR, thedevice spends a certain portion of the AC cycle time inthe ON state and the remainder of the time in the OFFstate. The amount of time spent in the ON state iscontrolled by the gate.

An SCR is fired by a short burst of current into thegate. This gate pulse must be more positive than thecathode voltage. Since there is a standard PN junc-tion between gate and cathode, the voltage betweenthese terminals must be slightly greater than 0.6V.Once the SCR has fired, it is not necessary to contin-ue the flow of gate current. As long as current contin-ues to flow from anode to cathode, the SCR willremain on. When the anode to cathode current dropsbelow a minimum value, called holding current, theSCR will shut off. This normally occurs as the AC sup-ply voltage passes through zero into the negative por-tion of the sine wave. If the SCR is turned on early inthe positive half cycle, the conduction time is longer,resulting in greater SCR output. If the gate firingoccurs later in the cycle, the conduction time is less,resulting in lower SCR output.


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Section F-1 Section F-1

LINCOLN ®

ELECTRIC

IDEALARC DC-400

Troubleshooting & Repair Section .................................................................................Section F

How to Use Troubleshooting Guide ......................................................................................F-2

PC Board Troubleshooting Procedures .................................................................................F-3

Troubleshooting Guide................................................................................................F-4 - F-14

Test ProceduresInput Contactor Test......................................................................................................F-15Control Transformer (T2) Voltage Test...........................................................................F-18Main Transformer (T1) Voltage Test...............................................................................F-21Static SCR/Diode Rectifier Bridge Test ........................................................................F-26Active SCR Test.............................................................................................................F-29

Oscilloscope Waveforms .....................................................................................................F-33Normal Open Circuit Voltage Waveform-Constant Current Mode................................F-33Normal Open Circuit Voltage Waveform-Constant Voltage FCAW/GMAW ..................F-34Normal Open Circuit Voltage Waveform-Constant Voltage Subarc .............................F-35Typical Output Voltage Waveform-Constant Voltage FCAW/GMAW............................F-36Typical Output Voltage Waveform-Constant Voltage Subarc .......................................F-37Typical SCR Gate Voltage Waveform-Constant Voltage Subarc ..................................F-38Abnormal Open Circuit Voltage Waveform-Constant Voltage Subarc..........................F-39

Replacement Procedures ....................................................................................................F-40Input Contactor (CR1) Cleaning/Replacement .............................................................F-40Fan Motor and Blade Removal and Replacement........................................................F-42SCR/Diode Rectifier Assembly Removal and Replacement.........................................F-44SCR Removal and Replacement ..................................................................................F-46Mounting of Stud Type Diodes to Aluminum Heat Sinks .............................................F-52Main Transformer Removal and Replacement..............................................................F-54

Retest After Repair ..............................................................................................................F-61

TABLE OF CONTENTSTROUBLESHOOTING & REPAIR SECTION

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HOW TO USE TROUBLESHOOTING GUIDE

Service and repair should be performed by only Lincoln Electric Factory Trained Personnel.Unauthorized repairs performed on this equipment may result in danger to the technician and machineoperator and will invalidate your factory warranty. For your safety and to avoid Electrical Shock, pleaseobserve all safety notes and precautions detailed throughout this manual.

TROUBLESHOOTING & REPAIRF-2 F-2

LINCOLN ®

ELECTRIC

IDEALARC DC-400

CAUTION

This Troubleshooting Guide is provided to helpyou locate and repair possible machine malfunc-tions. Simply follow the three-step procedurelisted below.

Step 1. LOCATE PROBLEM (SYMPTOM). Lookunder the column labeled “PROBLEM (SYMP-TOMS). This column describes possible symp-toms that the machine may exhibit. Find the list-ing that best describes the symptom that themachine is exhibiting. Symptoms are groupedinto two main categories: Output Problems andWelding Problems.

Step 2. PERFORM EXTERNAL TESTS. Thesecond column, labeled “POSSIBLE AREAS OFMISADJUSTMENT(S)”, lists the obvious externalpossibilities that may contribute to the machinesymptom. Perform these tests/checks in theorder listed. In general, these tests can be con-ducted without removing the case wrap-aroundcover.

Step 3. PERFORM COMPONENT TESTS. Thelast column, labeled “Recommended Course ofAction” lists the most likely components that mayhave failed in your machine. It also specifies theappropriate test procedure to verify that the sub-ject component is either good or bad. If there area number of possible components, check thecomponents in the order listed to eliminate onepossibility at a time until you locate the cause ofyour problem.

All of the referenced test procedures referred to inthe Troubleshooting Guide are described in detailat the end of this chapter. Refer to theTroubleshooting and Repair Table of Contents tolocate each specific Test Procedure. All of thereferred to test points, components, terminalstrips, etc., can be found on the referenced elec-trical wiring diagrams and schematics. Refer tothe Electrical Diagrams Section Table of Contentsto locate the appropriate diagram.

WARNING

If for any reason you do not understand the test procedures or are unable to perform the test/repairssafely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance beforeyou proceed. Call 216-383-2531 or 1-800-833-9353.


Have an electrician install and servicethis equipment. Turn the machine OFFbefore working on equipment. Do nottouch electrically hot parts.

Sometimes machine failures appear to be due to PCboard failures. These problems can sometimes betraced to poor electrical connections. To avoid prob-lems when troubleshooting and replacing PC boards,please use the following procedure:

1. Determine to the best of your technical ability thatthe PC board is the most likely component caus-ing the failure symptom.

2. Check for loose connections at the PC board toassure that the PC board is properly connected.

3. If the problem persists, replace the suspect PCboard using standard practices to avoid staticelectrical damage and electrical shock. Read thewarning inside the static resistant bag and performthe following procedures:

PC Board can be damaged bystatic electricity.

• Remove your body’s static chargebefore opening the static-shield-ing bag. Wear an anti-static wriststrap. For safety, use a 1 Megohm resistive cord connected to agrounded part of the equipmentframe.

• If you don’t have a wrist strap,touch an unpainted, grounded,part of the equipment frame.Keep touching the frame to pre-vent static build-up. Be sure notto touch any electrically live partsat the same time.

• Tools which come in contact with the PC Board mustbe either conductive, anti-static or static-dissipative.

• Remove the PC Board from the static-shielding bagand place it directly into the equipment. Don’t setthe PC Board on or near paper, plastic or cloth whichcould have a static charge. If the PC Board can’t beinstalled immediately, put it back in the static-shielding bag.

• If the PC Board uses protective shorting jumpers,don’t remove them until installation is complete.

• If you return a PC Board to The Lincoln ElectricCompany for credit, it must be in the static-shieldingbag. This will prevent further damage and allowproper failure analysis.

4. Test the machine to determine if the failure symp-tom has been corrected by the replacement PCboard.

NOTE: Allow the machine to heat up so that all elec-trical components can reach their operatingtemperature.

5. Remove the replacement PC board and substituteit with the original PC board to recreate the originalproblem.

a. If the original problem does not reappearby substituting the original board, then thePC board was not the problem. Continueto look for bad connections in the controlwiring harness, junction blocks, and termi-nal strips.

b. If the original problem is recreated by thesubstitution of the original board, then thePC board was the problem. Reinstall thereplacement PC board and test themachine.

6. Always indicate that this procedure was followedwhen warranty reports are to be submitted.

NOTE: Following this procedure and writing on thewarranty report, “INSTALLED AND SWITCHEDPC BOARDS TO VERIFY PROBLEM,” will helpavoid denial of legitimate PC board warrantyclaims.


LINCOLN ®

ELECTRIC

IDEALARC DC-400Ret

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PC BOARD TROUBLESHOOTING PROCEDURES

WARNING

ATTENTIONStatic-SensitiveDevicesHandle only atStatic-SafeWorkstations

ReusableContainerDo Not Destroy

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

Observe Safety Guidelines TROUBLESHOOTING GUIDEdetailed in the beginning of this manual.

CAUTIONIf for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call216-383-2531 or 1-800-833-9353.

PROBLEMS(SYMPTOMS)

POSSIBLE AREAS OFMISADJUSTMENT(S)

RECOMMENDEDCOURSE OF ACTION

OUTPUT PROBLEMS

Major physical or electrical dam-age is evident when the sheetmetal cover(s) are removed.

1. Contact your local authorizedLincoln Electric Field ServiceFacility for technical assistance.

1. Contact the Lincoln ElectricService Department, 216-383-2531 or 1-800-833-9353(WELD).

Machine is dead – no output – nofan – no pilot light.

1. Make sure that the input Powerswitch is in the “ON” position.

2. Check the three-phase inputvoltage at the machine. Inputvoltage must match the ratingplate and the reconnect panel.

3. Check for blown or missingfuses in the input lines.

1. Check the Power switch (S1) forproper operation.

2. Check the leads associatedwith the Power switch (S1) andthe control transformer (T2) forloose or faulty connections.See Wiring Diagram.

3. Perform the Control Trans-former Test.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

TROUBLESHOOTING GUIDE Observe Safety Guidelinesdetailed in the beginning of this manual.


PROBLEMS(SYMPTOMS)



OUTPUT PROBLEMSThe machine is dead – no output –no fan – the pilot light is lit.

1. Check the three-phase inputvoltage at the machine. Inputvoltage must match the ratingplate and the reconnect panel.

2. Check for blown or missingfuses in the input lines.

1. Perform the Input ContactorTest.

2. Check the associated leads, forloose or faulty connections,between the input contactor(CR1), the reconnect panel andthe main transformer. SeeWiring Diagram.

3. Perform the Main TransformerTest.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400



PROBLEMS(SYMPTOMS)



OUTPUT PROBLEMS

The input contactor operates – thefan runs – the pilot light is lit – butthe machine has no welding out-put.

1. If the amber thermal protectionlight is lit, the primary or sec-ondary thermostat is open.Allow machine to cool.

2. Make certain the output triggercircuit (#2 and #4) is being acti-vated either by an external “clo-sure” or by the output terminalsswitch (S3).

3. Check the 10A circuit breaker inthe 42VAC line.

4. If remote control is not beingused, make certain the OutputControl switch (S2) is in theOUTPUT CONTROL “LOCAL”position.

5. Check for loose or faulty weldcable connections.


2. Perform the SCR/DiodeRectifier Bridge Test.

3. The control board may befaulty. Replace.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400



PROBLEMS(SYMPTOMS)



OUTPUT PROBLEMS

The machine has high welding out-put and no control.

1. If remote control is being used,set the Output Control switch(S2) in the OUTPUT CONTROL“LOCAL” position and controlthe weld output with themachine Output Control poten-tiometer (R4). If the problem issolved, check the remote con-trol unit (or wire feeder) andassociated control cable.

1. Check the Output Controlswitch (S2) and associatedwiring.

2. Check feedback leads #225(negative output terminal), #205and #206 (output shunt) forloose or faulty connections.See Wiring Diagram.

3. Perform the SCR/Diode Rec-tifier Bridge Test.


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LINCOLN ®

ELECTRIC

IDEALARC DC-400



PROBLEMS(SYMPTOMS)



OUTPUT PROBLEMS

The machine has minimum weldingoutput and no control.

1. If remote control is being used,set the Output Control switch(S2) in the OUTPUT CONTROL“LOCAL” position and controlthe weld output with themachine Control potentiometer(R4). If the problem is solved,check the remote control unit(or wire feeder) and associatedcontrol cable.

2. Make certain the remote controlleads (#75, #76 and #77) are notgrounded to the positive weld-ing output.

3. Make certain the three-phaseinput voltage is correct andmatches the machine rating andthe reconnect panel.

1. Check the Output Controlpotentiometer (R4) and associ-ated wiring. See WiringDiagram.

2. Check the welding Mode switch(S4), the microswitches, and theassociated wiring.

3. Check the Output Controlswitch (S2) and associatedwiring. See Wiring Diagram.



6. The control board may be faulty.Replace.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400



PROBLEMS(SYMPTOMS)



OUTPUT PROBLEMS

The machine does not have maxi-mum output.

1. Make certain the correct three-phase input voltage is beingapplied to the machine.

2. If remote control is being used,set the Output Control switch(S2) in the OUTPUT CONTROL“LOCAL” position and controlthe weld output with themachine Control potentiometer(R4). If the problem is solved,check the remote control unit(or wire feeder) and associatedcontrol cable.

1. Check the Output Controlpotentiometer (R4). Normalresistance is 10,000 ohms.Also check associated wiringfor loose or faulty connections.See Wiring Diagram.


3. Check the Output Controlswitch (S2) and associatedwiring. See Wiring Diagram.




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LINCOLN ®

ELECTRIC

IDEALARC DC-400



PROBLEMS(SYMPTOMS)



FUNCTION PROBLEMS

The machine will not shut off whenthe power switch is put in the OFFposition.

1. Make sure the three-phaseinput lines are connected cor-rectly to the DC-400.

1. Check the Input Power switch(S1) and the associated leads.See Wiring Diagram.

2. Perform the Input ContactorTest.

The Arc Control switch (S5) has noeffect in CV (FCAW/GMAW) modewhen welding with the short circuittransfer process.

1. Make sure the correct processand gas are being used.

1. Check the Arc Control switch(S5) for proper operation.


3. Check to make sure the outputchoke control coil is not “open”or grounded. See WiringDiagram.

4. Check resistor R1. Normalresistance is 15 ohms.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400



PROBLEMS(SYMPTOMS)



OUTPUT PROBLEMS

The output terminals are alwayselectrically “hot.”

1. Make certain the OutputTerminals switch (S3) is in the“REMOTE” position.

2. Remove any external leadshooked to the 14 pin amphenoland/or the terminal strip. If theproblem disappears, the fault isin the control cable or wirefeeder.

1. Check for an internal shortbetween leads #2 and #4. SeeWiring Diagram.

2. Check the Output Terminalsswitch (S3) for proper opera-tion. Also check associatedleads. See Wiring Diagram.

3. Remove plug P3 (SCR gateleads) from the control board. Ifthe problem disappears, thecontrol board may be faulty.Replace. If the output terminalsare still electrically “hot,” per-form the SCR/Diode RectifierBridge Test.

4. The snubber board may beleaky. Check or replace.

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F-12 F-12

LINCOLN ®

ELECTRIC

IDEALARC DC-400

TROUBLESHOOTING & REPAIR



PROBLEMS(SYMPTOMS)



WELDING PROBLEMS

Poor arc striking when using semi-automatic or automatic wirefeeders.

1. Make sure the correct weld pro-cedures are being used.(Electrode, Gas, Etc.)

2. Check the welding cables forloose or faulty connections.

1. Check reed switch CR3 forproper operation. Switchshould be normally open untilweld current is established.

2. The start board may be faulty.Replace.


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LINCOLN ®

ELECTRIC

IDEALARC DC-400


PROBLEMS(SYMPTOMS)



WELDING PROBLEMS

Poor arc characteristics whenwelding in the constant voltage(CV) mode.

1. Make sure the correct weld pro-cedures are being used.(Electrode, Gas, Etc.)

2. Check the welding cables forloose or faulty connections.

1. Check reed switch CR3 forproper operation. Switchshould be normally open untilweld current is established.

2. Remove plug P6 from the startboard. If problem is resolved,the start board may be faulty.Replace. See Wiring Diagram.

3. Check the welding Modeswitch (S4), the microswitches,and the associated wiring.

4. Check the output capacitorsand connections. A capacitorfailure is indicated if the smallvent plug on top of a capacitoris raised or blown out.

WARNING: The liquid elec-trolyte in these capacitors istoxic. Avoid contact with anyportion of your body. Cleanup vented electrolyte usingrubber gloves and a waterdamped cloth. Any elec-trolyte which gets on skin,clean with soap and water.


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LINCOLN ®

ELECTRIC

IDEALARC DC-400


PROBLEMS(SYMPTOMS)



WELDING PROBLEMS

The Arc Force control (R5) has noeffect on the arc.

1. The Arc Force control is activeonly in the Stick Mode.

2. The effect of the Arc Force con-trol will be less noticeable athigh welding currents. Weld atlow currents (less than 150amps) and check the Arc Forcecontrol function.

1. Check the Arc Force controlpotentiometer (R5) for correctresistance and proper opera-tion. Normal resistanace is10,000 ohms.

2. Check the continuity of leads#204, #208, and #209 from theArc Force control to the controlboard.


The welding arc is variable andsluggish.

1. Check the input voltage at theDC-400, making sure the cor-rect voltage and all threephases are being applied to themachine.

2. Make sure welding process iscorrect for machine settings.

3. Check welding cables for looseor faulty connections. Alsomake sure cables are sized cor-rectly for welding current.




4. The control board may be faulty.Replace.


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LINCOLN ®

ELECTRIC

IDEALARC DC-400

INPUT CONTACTOR TEST

WARNING

Service and repair should be performed by only Lincoln Electric factory trained person-nel. Unauthorized repairs performed on this equipment may result in danger to the tech-nician or machine operator and will invalidate your factory warranty. For your safety andto avoid electrical shock, please observe all safety notes and precautions detailedthroughout this manual.

If for any reason you do not understand the test procedures or are unable to perform thetest/repairs safely, contact the Lincoln Electric Service Department for electrical trou-bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353(WELD).

DESCRIPTION

This test will help determine if the input contactor is receiving the correct coil voltage andif the contacts are functioning correctly.

MATERIALS NEEDED

Volt/Ohmmeter (Multimeter)5/16” Nut driverIdealarc DC 400 Wiring Diagrams (See the Electrical Diagrams section of thismanual.)External 120VAC supply

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

INPUT CONTACTOR TEST (continued)

TEST PROCEDURE

1. Disconnect the main input supply power tothe machine.

2. With the 5/16” nut driver, remove the casetop and the reconnect panel cover.

3. Locate the two leads connected to the inputcontactor coil, #233 and X1 #232 (top). SeeFigure F.1 for location.

4. Connect an AC voltmeter to the leads.

Electric Shock can kill.

• With the input power on,there are high voltagesinside the machine. Donot reach into themachine or touch anyinternal part of themachine while thepower is on.

5. Apply the correct voltage to the machineand turn the power switch (S1) ON.

6. Check for 120VAC at the contactor coilleads.

If the 120VAC is NOT present, with thepower switch (S1) on, check the powerswitch (S1) and associated circuitry. See theWiring Diagram. Also perform the ControlTransformer (T2) Voltage Test.

If the 120VAC is present and the contactordoes NOT activate, then the input contactoris faulty. Replace the input contactor.

WARNING

FIGURE F.1 – INPUT CONTACTOR CONNECTIONS

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

TEST FOR CONTACT CONTINUITY


2. Remove the two leads connected to theinput contactor coil, #233 and X1/#232. SeeFigure F.1 for location.

3. Using the external 120VAC supply, apply120VAC to the terminals of the input con-tactor coil. If the contactor does NOT acti-vate, the input contactor is faulty. Replacethe input contactor.

4. With the contactor activated, check the con-tinuity across the contacts. (Zero ohms orvery low resistance is normal.) See FigureF.2. If the resistance is high, the input con-tactor is faulty. Replace the input contactor.

5. When the contactor is NOT activated, theresistance should be infinite or very highacross the contacts. If the resistance is low,the input contactor is faulty. Replace theinput contactor.

INPUT CONTACTOR TEST (continued)

FIGURE F.2 – INPUT CONTACTOR TEST CONNECTIONS

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

CONTROL TRANSFORMER (T2) VOLTAGE TEST

Service and repair should be performed by only Lincoln Electric factory trained personnel.Unauthorized repairs performed on this equipment may result in danger to the technician ormachine operator and will invalidate your factory warranty. For your safety and to avoid elec-trical shock, please observe all safety notes and precautions detailed throughout this manu-al.

If for any reason you do not understand the test procedures or are unable to perform thetest/repairs safely, contact the Lincoln Electric Service Department for electrical trou-bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).

DESCRIPTION

This test will determine if the correct voltage is being applied to the primary of the controltransformer and induced on the secondary winding of the control transformer.

MATERIALS NEEDED

Volt/Ohmmeter (Multimeter)5/16” Nut driverIDEALARC DC-400 Wiring Diagrams (See the Electrical Diagrams section of this manual.)

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

CONTROL TRANSFORMER (T2) VOLTAGE TEST (continued)

FIGURE F.3 – CONTROL TRANSFORMER AND LEAD LOCATIONS

TEST PROCEDURE


2. With the 5/16” nut driver, remove the top,case sides, and lower the front controlpanel.

3. Locate the control transformer (T2) on theleft side of the input box (facing the backof the machine). See Figure F.3.

4. Locate the control transformer primaryleads (H1, H2, H3, etc.). See the WiringDiagram.

NOTE: Unused leads should be taped.

a. Inspect for broken or incorrect con-nections.

5. Locate control transformer leads X1 (top)and X2.

a, Lead X1 is connected to the input con-tactor (CR1) coil located on the inputside of the contactor. See Figure F.3.

b. Lead X2 is spliced into lead #231. Seethe Wiring Diagram. Lead #231 isconnected to the power switch (S1).Remove five machine screws holdingthe control panel to the case front andtilt the panel forward to access thepower switch and Lead #231 connec-tion. See Figure F.4.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

CONTROL TRANSFORMER (T2) VOLTAGE TEST (continued)

6. Test for 115VAC between leads X1 and#231.

NOTE: If the main AC input supply voltagevaries, the control transformer voltage willvary by the same percentage.

a. Connect one end of an insulated alliga-tor clip to the X1 connection at theinput contactor (CR1) coil. See FigureF.4.

b. Connect the other end of the alligatorclip to one of the meter probes. Besure that neither the alligator clip northe meter probe touches any metalsurfaces.

c. Connect the other meter probe to the#231 connection (top lead) at thepower switch. See Figure F4.

d. Apply input power to the DC-400.

7. Read the meter for 115VAC.

a. If 115VAC is present, the control trans-former is functioning properly.

b. If 115VAC is NOT present, go to Step8.

8. If 115VAC is not present between leads X1and #231, check the spliced connectionbetween #231 and X2. Test for correctmain input supply power to the controltransformer primary windings (H1, H2, H3,etc.). Check the main input supply powerhookup to the machine. See the WiringDiagram.

a. If the correct main input supply powerto the control transformer primarywindings is present AND the secondaryvoltage is not correct, the control trans-former may be faulty. Replace.

FIGURE F.4 – CONTROL TRANSFORMER X1 AND X2 TEST CONNECTIONS

RIGHTSIDE VIEW

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

MAIN TRANSFORMER (T1) VOLTAGE TEST

Service and repair should be performed by only Lincoln Electric factory trained personnel.Unauthorized repairs performed on this equipment may result in danger to the technician ormachine operator and will invalidate your factory warranty. For your safety and to avoid elec-trical shock, please observe all safety notes and precautions detailed throughout this man-ual.


DESCRIPTION

This test will determine if the correct voltages are being applied to the primary windings ofthe Main Transformer (T1) and induced on the secondary winding, auxiliary windings, andphase angle windings.

MATERIALS NEEDED

Volt/Ohmmeter (Multimeter)5/16” Nut driverIDEALARC DC-400 Wiring Diagram (See Electrical Diagrams section of Manual.)

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

MAIN TRANSFORMER (T1) VOLTAGE TEST (continued)

FIGURE F.5 – INPUT CONTACTOR, RECONNECT PANEL, AND PRIMARY LEADSTO MAIN TRANSFORMER LOCATIONS

TEST PROCEDURE

1. Set the ON/OFF power switch to OFF.

2. Disconnect main input supply power fromthe machine.

3. With the 5/16” nut driver, remote the casetop and sides and the reconnect panelcover.

4. Inspect the input contactor, reconnectpanel, and primary leads to the main trans-former for loose or faulty connections. SeeFigure F.5.

a. Confirm that the reconnect panel isconnected properly for the three-phasemain input supply power supplied tothe machine. See the reconnect panelconnection diagram located on theinside of the input box assemblyaccess door.

5. Connect main input supply power to themachine.

6. Set the ON/OFF power switch to ON.

a. Make sure the input contactor (CR1)energizes and the fan runs.

7. Test with an AC voltmeter for proper maininput supply voltage to the line side of theinput contactor (CR1). See the WiringDiagram.

a. L1 to L2.

b. L2 to L3.

c. L1 to L3.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

8. Read the meter.

a. If proper voltage is present for all threephases, proper main input supply volt-age is being supplied.

b. If proper voltage is not present in anyor all of the three phases, check inputfuses and leads.

9. Test with an AC voltmeter for proper maininput supply voltage from the output side ofthe input contactor (CR1). See the WiringDiagram.

a. T1 to T2.

b. T2 to T3.

c. T1 to T3.

10. Read the meter.

a. If proper voltage is present for all threephases, the input contactor is workingproperly.

b. If the proper voltage is not present forany or all of the three phases, the inputcontactor may be faulty. Replace theinput contactor.

11. Test with an AC voltmeter for approximate-ly 42VAC across each of the three mainsecondary start leads located at theSCR/Diode Rectifier Bridge. Remove thered insulating paint to achieve good con-tact if necessary. See Figure F.6. See theWiring Diagram.

a. If one or more of the above voltagetests are incorrect, check for loose orfaulty connections.

b. If the connections are good, then themain transformer may be faulty. Re-place the main transformer.


FIGURE F.6 – MAIN SECONDARY LEAD TEST POINTS

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

12. Test for 115VAC between leads #31 and#32 on the terminal strip. Also test for42VAC between pin K (lead #42) and pin I(lead 41) in the 14 pin amphenol.

a. Remove the sheet metal screws fromthe control box cover with the 5/16”nut driver and flip the cover down. Itdoes not have to be completelyremoved to perform the tests.

b. If the above voltage checks are incor-rect, check for loose or faulty wiring.Check continuity.

c. If the wiring is good, then the maintransformer may be faulty. Replace themain transformer.

13. Test with an AC voltmeter for 21VAC foreach phase angle winding at plug P1 onthe control board as shown in Figure F.8and the accompanying table.

NOTE: If the main input supply voltagevaries, the main transformer voltages willvary proportionately.

a. If the voltage is low, remove plug P1and recheck the voltage for 21VAC. Ifthe reading is normal, the control boardmay be faulty. Replace the controlboard.

b. If one or more of the voltage tests areincorrect, check for loose or faultywiring.

c. If the wiring is good, then the maintransformer may be faulty. Replace themain transformer.


FIGURE F.7 – PHASE ANGLE WINDINGS TEST POINTS AND TERMINAL STRIP LOCATION

I

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

Plug P1 PHASE ANGLE WINDING VOLTAGES

From Lead # To Lead # Expected VAC

201 204 21 VAC

202 204 21 VAC

203 204 21 VAC


FIGURE F.8 – CONTROL BOARD PLUG P1 LOCATION

DC-400 CONTROLG2588-X

Plug P1

#201#202#203#204

Plug P3

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

STATIC SCR/DIODE RECTIFIER BRIDGE TEST



DESCRIPTION

This test will help determine if an SCR or diode is shorted or “leaky.” See the MachineWaveform Section in this manual for normal and abnormal output waveforms.

MATERIALS NEEDED

Analog Volt/Ohmmeter (Multimeter)5/16” Nut driverIdealarc DC-400 Wiring Diagrams (See the Electrical Diagrams section of this manual.)

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

STATIC SCR/DIODE RECTIFIER BRIDGE TEST (continued)

FIGURE F.9 – CONTROL BOARD AND SNUBBER BOARD PLUG LOCATIONS

FIGURE F.10 – RESISTOR R2 LOCATION

TEST PROCEDURE


2. With the 5/16” nut driver, remove the casetop and sides.

3. Disconnect the welding cables from thewelding output terminals.

4. Locate and remove molex plugs P1 and P3from the control board. See Figure F.9.

5. Locate and remove molex plug P5 from thesnubber board. See Figure F.9.

6. Rotate the mode switch (S4) to the constantcurrent (CC) position.

7. Locate and remove lead #204 from resistorR2 (40 ohms, 50 Watts). See Figure F.10.


Plug P1

Plug P3

M15370-X SNUBBER

Plug P5

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

STATIC SCR/DIODE RECTIFIER BRIDGE TEST (continued)

8. Remove the red insulating paint from theheat sink test points. See Figure F.11.

NOTE: Do not disassemble the heat sink.

9. Measure the resistance from the anode tothe cathode of SCR 1 using an analogvolt/ohmmeter (multimeter) set at R x 1000scale. See Figure F.11.

a. Reverse the meter leads and measurethe resistance from the cathode to theanode of SCR 1. See Figure F.11.

b. If a low resistance is measured ineither meter polarity, SCR1 is faulty.Replace SCR 1.

10. Test the resistance of SCR 2 and SCR 3using the same procedure described inStep 9.

11. Measure the resistance of diode D1 fromanode (+probe) to cathode (-probe) usingan analog ohmmeter set at R x 1000 scale.The resistance should be low. See FigureF.11.

a. Reverse the meter leads and measurethe resistance from cathode (+probe)to anode (-probe) of diode D1. Theresistance should be high. See FigureF.11.

b. If a low resistance is measured in bothmeter polarities, diode D1 is shorted.Replace diode D1.

c. If a high resistance is measured in bothmeter polarities, diode D1 is open.Replace diode D1.

12. Test diodes D2, D3 and D4 for proper oper-ation using the same procedure describedin Step 11.

13. Reconnect all leads and molex plugs.

14. If this test did not identify the problem or tofurther test the SCRs, go to the ActiveSCR Test.

FIGURE F.11 – HEAT SINK AND SCR TEST POINTS

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

ACTIVE SCR TEST



DESCRIPTION

This test will help determine if the device can be gated ON and conduct current from anodeto cathode.

MATERIALS NEEDED

An SCR tester as specified in this procedure.5/16” Nut driverIdealarc DC-400 Wiring Diagrams (See the Electrical Diagrams section of this manual.)

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

ACTIVE SCR TEST (continued)

TEST PROCEDURE


2. With the 5/16” nut driver, remove the casetop and sides. Remove the screws holdingthe front panel and lower the panel.

3. Disconnect the welding cables from thewelding output terminals.

4. Locate and remove molex plugs P1 and P3from the control board. See Figure F.12.

5. Locate and remove molex plug P5 from thesnubber board. See Figure F.13.

6. Rotate the mode switch (S4) to the constantcurrent (CC) position.

7. Locate and remove lead #204 from resistorR2 (40 ohms, 50 Watts). See Figure F.14.

FIGURE F.12 – CONTROL BOARD PLUGP1 AND P3 LOCATIONS

FIGURE F.13 – SNUBBER BOARDPLUG P5 LOCATION

FIGURE F.14 – RESISTOR R2 LOCATION


Plug P1

Plug P3

M15370-X SNUBBER

Plug P5

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LINCOLN ®

ELECTRIC

IDEALARC DC-400


8. Remove the red insulating paint from theheat sink test points. See Figure F.15.

NOTE: Do not disassemble the heat sinks.

FIGURE F.15 – HEAT SINK TEST POINTS

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LINCOLN ®

ELECTRIC

IDEALARC DC-400


9. Construct the circuit shown in Figure F.16.One 6-volt lantern battery can be used., Setvoltmeter scale low, at approximately 0-5volts or 0-10 volts.

10. Test the voltage level of the battery. Shortleads (A) and (C). Close switch SW-1.Battery voltage should be 4.5 volts or higher.If lower, replace the battery.

11. Connect the tester to the SCR 1 as shown inFigure F.16.

a. Connect tester lead (A) to the anode.

b. Connect tester lead (C) to the cathode.

c. Connect tester lead (G) to the gate.

12. Close switch SW-1.

NOTE: Switch SW-2 should be open.

13. Read meter for zero voltage.

a. If the voltage reading is higher than zero,the SCR is shorted.

14. Close or keep closed switch SW-1.

15. Close switch SW-2 for 2 seconds. Releaseand read meter.

a. If the voltage is 3-6 volts while the switchis closed and after the switch is open,the SCR is functioning.

b. If the voltage is 3-6 volts only when theswitch is closed or if there is no voltagewhen the switch is closed, the SCR isdefective.

NOTE: Be sure the battery is function-ing properly. A low battery can affect theresults of the test. Repeat Battery TestProcedure in Step 10 if needed.

16. Open switch SW-1.

17. Reconnect the tester leads. See Figure F.16.

a. Connect tester lead (A) to the cathode.

b. Connect tester lead (C) to the anode.

c. Disconnect test lead (G) from the gate.

18. Close switch SW-1.

19. Read meter for zero voltage.

a. If the voltage is zero, the SCR is func-tioning.

b. If the voltage is higher than zero, theSCR is shorted.

20. Perform the Active Test Procedure outlinedin Steps 11-19 for SCRs 2 and 3.

21. Replace all SCR assemblies that do not passthe above tests.

22. Replace all molex plugs onto the controlboard and snubber board. Reconnect lead#204 to resistor R2.

FIGURE F.16 – SCR TESTER CIRCUIT AND SCR CONNECTIONS

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

This is the typical DC open circuitvoltage waveform generated from aproperly operating machine. Notethat each vertical division represents50 volts and that each horizontal divi-sion represents 2 milliseconds intime.

Note: Scope probes connected atmachine output terminals: (+) probeto positive terminal, (-) probe to neg-ative terminal.

SCOPE SETTINGS

Volts/Div.....................50V/Div.Horizontal Sweep.....2 ms/Div.Coupling ............................DCTrigger .........................Internal

NORMAL OPEN CIRCUIT VOLTAGE WAVEFORMCONSTANT CURRENT MODE – NO LOAD

CH1

0 volts

2 ms50 volts

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LINCOLN ®

ELECTRIC

IDEALARC DC-400



SCOPE SETTINGS


NORMAL OPEN CIRCUIT VOLTAGE WAVEFORMCONSTANT VOLTAGE FCAW/GMAW

MAXIMUM OUTPUT SETTING – NO LOAD

CH1

0 volts

2 ms20 volts

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LINCOLN ®

ELECTRIC

IDEALARC DC-400



SCOPE SETTINGS


NORMAL OPEN CIRCUIT VOLTAGE WAVEFORMCONSTANT VOLTAGE SUBARC


CH1

0 volts

5 ms20 volts

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

This is the typical DC open circuitvoltage waveform generated from aproperly operating machine. Notethat each vertical division represents20 volts and that each horizontal divi-sion represents 5 milliseconds intime. The machine was loaded witha resistance grid bank. The DC-400meters read 400 amps at 36 VDC.


SCOPE SETTINGS


TYPICAL OUTPUT VOLTAGE WAVEFORM – MACHINE LOADEDCONSTANT VOLTAGE FCAW/GMAW MODE

CH1

0 volts

5 ms20 volts

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

This is the typical DC open circuitvoltage waveform generated from aproperly operating machine. Notethat each vertical division represents20 volts and that each horizontal divi-sion represents 5 milliseconds intime. The machine was loaded witha resistance grid bank. The DC-400meters read 400 amps at 36 VDC.


SCOPE SETTINGS


TYPICAL OUTPUT VOLTAGE WAVEFORM – MACHINE LOADEDCONSTANT VOLTAGE SUBARC MODE

CH1

0 volts

5 ms20 volts

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

This is the typical SCR gate pulsevoltage waveform. The machine wasin an open circuit condition (no load)and operating properly. Note thateach vertical division represents 2volts and that each horizontal divisionrepresents 5 milliseconds in time.

Note: Scope probes connected atSCR gate and cathode: (+) probe togate, (-) probe to cathode.

SCOPE SETTINGS

Volts/Div.......................2V/Div.Horizontal Sweep.....5 ms/Div.Coupling ............................DCTrigger .........................Internal

TYPICAL SCR GATE VOLTAGE WAVEFORMCONSTANT VOLTAGE SUBARC


CH1

0 volts

5 ms2 volts

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

This is NOT the typical DC outputvoltage waveform. One output SCRis not functioning. Note the “gap” inthe waveform. One SCR gate is dis-connected to simulate an open ornon-functioning output SCR. Eachvertical division represents 20 voltsand each horizontal division repre-sents 5 milliseconds in time.


SCOPE SETTINGS


ABNORMAL OPEN CIRCUIT VOLTAGE WAVEFORMCONSTANT VOLTAGE SUBARC

ONE OUTPUT SCR NOT FUNCTIONING

CH1

0 volts

5 ms20 volts

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

INPUT CONTACTOR (CR1) CLEANING/REPLACEMENT



DESCRIPTION

The following procedure will aid the technician in inspecting, cleaning, and replacing the inputcontactor.

MATERIALS NEEDED

Phillips head screwdriver5/16” socket wrenchFlat heat screw driverLow pressure air source

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

INPUT CONTACTOR (CR1) CLEANING/REPLACEMENT (continued)

FIGURE F.17 – INPUT CONTACTOR CLEANING AND REMOVAL

CLEANING PROCEDURE

1. Remove the main input supply power to themachine.

2. Locate and get access to the input contac-tor (CR1) in the input box. See Figure F.17.

3. Remove the input contactor cover plateusing a phillips head screwdriver.

Do not apply input power tothe machine with the inputcontactor cover plate re-moved.

4. Blow out any dirt or dust in or around thecontacts with a low pressure air stream.

5. Inspect the contacts for signs of excessivewear, pitting, or contacts fused (stuck)together.

a. If any of these conditions are present,replace the input contactor assembly.

6. Replace the input contactor cover plate.

CONTACTOR REPLACEMENTPROCEDURE

1. Disconnect main input supply power to themachine.

2. Locate and get access to the input contac-tor (CR1) in the input box. See Figure F.17.

3. Disconnect the main input supply powerleads L1, L2, and L3 to the input contactor.

Remove the control transformer primaryleads H1, H2 or H3 (dependent on input volt-age) from L1 and L3 terminals on the inputside of the contactor.

4. Disconnect the output leads T1, T2, and T3from the input contactor.

5. Identify and label the leads connected to theinput contactor coil. See the WiringDiagram.

6. Disconnect the leads from the input contac-tor coil (leads X1, #232 and #233). See theWiring Diagram.

7. Remove the three self-tapping mountingscrews using a 5/16” socket wrench. SeeFigure F.17.

8. Remove the input contactor.

9. Insert the replacement input contactor andinstall it following the procedures in reverseorder.

NOTE: Be sure to reconnect all leads cor-rectly.

WARNING

1. INPUT SUPPLY LINE2. INPUT CONTACTOR CR13. RECONNECT PANEL

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

FAN MOTOR AND BLADE REMOVAL AND REPLACEMENT



DESCRIPTION

The following procedure will aid the technician in gaining access to the fan blade and fanmotor for maintenance or replacement.

MATERIALS NEEDED

5/16” Nut driver3/8” WrenchAllen head type wrench

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

FAN MOTOR AND BLADE REMOVAL AND REPLACEMENT (continued)

FIGURE F.18 – FAN MOTOR MOUNTING DETAILS

PROCEDURE


2. Using the 5/16” nut driver, remove the casetop and sides.

3. The fan blade can be removed using theAllen head wrench.

NOTE: You may need to loosen themachine case back to gain clearance toremove the fan. See Figure F.18.

4. If the fan motor is to be removed, the leadsto the motor must be disconnected. Thiswill require cutting the wires or “breaking thesplice.”

5. Remove the four mounting nuts and associ-ated flat and lock washers that hold themotor to the mounting bracket. See FigureF.18.

6. Carefully remove the fan motor.

7. To replace the fan motor, mount the motor toits mounting bracket using the four nut andassociated flat and lock washers.

8. Resplice any motor leads cut for removal.Soldering the wires is recommended.

9. Reattach the fan blade, if it was removedearlier, using the Allen head wrench totighten it to the motor shaft.

10. Install the case top and sides.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

SCR/DIODE RECTIFIER ASSEMBLYREMOVAL AND REPLACEMENT



DESCRIPTION

The following procedure will aid the technician in the removal and replacement of the SCR/diode assembly.

MATERIALS NEEDED

5/16” Nut driver7/16” Wrench1/2” Wrench9/16” Wrench3/8” WrenchSlot head screw driver1/2” Socket and extension

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

SCR/DIODE RECTIFICER ASSEMBLYREMOVAL AND REPLACEMENT (continued)

FIGURE F.19 – SCR/DIODE ASSEMBLY DETAILS

PROCEDURE1. Remove the main input supply power to the

machine.


3. Remove the glastic stiffeners (one on eachside-left and right). See Figure F.19.

4. Remove the positive capacitor lead andshunt from the positive heat sink plate. SeeFigure F.19.

5. Remove the choke and mode switch leadfrom the left side of the negative heat sinkplate. See Figure F.19.

6. Remove the gate leads from the controlboard (plug P3).

7. Remove plug P5 from the snubber board.Also remove lead #224 from the positiveoutput lead. Remove lead #225 from thenegative output lead. Remove the greenground lead from the front panel.

8. Remove the three heavy aluminum sec-ondary leads from the SCR finned heatsinks.

9. Remove the four nuts and associated wash-ers that hold the SCR/diode assembly to themounting brackets.

10. Carefully lift and remove the SCR/diode heatsink assembly from the machine. Note: Itmay be necessary to loosen the six sheetmetal screws that hold the front panel to thebase. Carefully lift and pull out the front

panel to allow clearance for SCR/diodeassembly removal. Clear any necessaryleads that might hinder removal.

11. For reassembly, carefully place the SCR/diode assembly into position on the mount-ing bracket and reinstall the washers andnuts. Tighten the front panel to base if it wasloosened earlier.

12. Replace and tighten the four nuts and lock-washers that hold the SCR/diode assemblyto the mounting brackets.

13. Reattach the three heavy aluminum sec-ondary leads to the SCR finned heat sinks.Apply a thin coating of Dow Corning 340heat sink compound (Lincoln E1868) to con-nection points.

14. Connect the green ground lead to the frontpanel, lead #225 to the negative output lead,and lead #224 to the positive output lead.

15. Connect plug P5 to the snubber board andplug P3 to the control board.

16. Connect the choke and mode switch lead tothe left side of the negative heat sink plate.See Figure F.19.

17. Connect the positive capacitor lead andshunt to the positive heat sink plate. SeeFigure F.19.

18. Install the glastic stiffeners to the left andright sides. See Figure F.19.


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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

SCR REMOVAL AND REPLACEMENT



DESCRIPTION

The following procedure will aid the technician in removing the SCRs from the output rectifierheat sink for maintenance or replacement.

MATERIALS NEEDED

NO.000 Fine Steel WoolPenetrox A-13 (Lincoln E2529) or Penetrox A7/16” Open end wrenchAllen head type wrenches

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

FIGURE F.20 – SCR DETAILS

SCR REMOVAL AND REPLACEMENT (continued)

SPECIAL INSTRUCTIONS

NOTE: Before disassembling the existing recti-fier, note toward which heat sink the outer metalring of the power SCR is mounted. Also, notethe positioning of the gate lead of the SCR.Failure to reinstall the new SCR in the same ori-entation as the original may result in subsequentdamage to the new SCR and other componentsof the welder. See Figure F.20.

The unclamping and clamping procedure out-lined below is critical for the prevention of inter-nal SCR damage. Failure to follow this proce-dure may result in subsequent damage of theSCR. Handle all SCRs with care.

PROCEDURE


2. Perform the SCR/Diode RectifierAssembly Removal and Replacement pro-cedure.

3. Alternately loosen nuts 1/2 turn each untilheat sinks are loose. Remove nuts and leafspring. IT IS RECOMMENDED THAT NEWHARDWARE, LEAF SPRING AND HOUSINGBE USED FOR REASSEMBLY.

4. Remove the old SCR.

5. Clean the area on the heat sink around theSCR mounting surface, using a putty knife orsimilar tool. DO NOT SCRATCH THE SCRMOUNTING SURFACE.

6. Polish each heat sink’s mounting surfaceusing NO. 000 fine steel wool. Wipe surfaceclean with a lint-free cloth or paper towel.

7. Inspect the mounting surfaces of each newSCR.

a. Remove all burrs and wipe clean. Donot use steel wool or any abrasivecleanser on the SCR mounting surfaces.

8. Apply a thin (0.001” to 0.003”) layer of PEN-ETROX A-13 (Lincoln Electric #E2529) orPENETROX A, heat sink compound, to eachheat sink’s SCR mounting surface.

a. Care must be used to prevent foreignmaterial contamination of the SCR toheat sink junction.

9. Place the new SCR between the heat sinks.Be sure that the outer metal ring of the SCRis facing toward the same heat sink as theold SCR’s metal ring. Be sure that the rollpin of the heat sink engages the “hole” in theSCR. The SCR contact surfaces must sit flatagainst both heat sink surfaces.

CAUTION

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

FIGURE F.21 – 1/2” WIDE LEAF SPRING FIGURE F.22 – CLAMP ASSEMBLY


10. Go to the procedure below that matches yourmachine’s cap screws. NOTE WHICH THREAD ISON YOUR CAP SCREWS BEFORE PROCEEDINGTO THE ASSEMBLY PROCEDURE. Two differentdesigns of leaf springs and housings have beenused to clamp the SCR to the rectifier. The twodifferent designs can be identified by the size ofthe leaf spring. One design uses a 1/2 inch wideleaf spring, and the other uses a 5/8 inch widespring. The different designs require differentassembly and clamping procedures. The assem-bly procedure will be different depending upon thethread on the cap screws. A 1/4-28 threadrequires a different tightening procedure than a1/4-20 thread.

PROCEDURE FOR THE 1/2 INCH WIDESPRING

1. Place a piece of sleeving around each cap screw.

2. Insert cap screws through the leaf spring. Orientthe leaf spring so that its ends are curved upwardtoward the cap screw heads. See Figure F.21.Pressing on the cap screw heads should producea “rocking” motion of the spring in its housing. Ifthe spring does NOT rock, it is installed upsidedown. Remove the spring and turn it over. Checkfor “rocking” motion. See Figure F.21.

3. Insert cap screws and leaf spring into the plastichousing.

4. Insert clamp assembly through heat sinks. Installnuts. Tighten clamp nuts equally on cap screwsuntil finger tight. (See Figure F.22. Heat sinks maynot be exactly as pictured.)

5. Reinspect the SCR for proper seating.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400


CLAMPING PROCEDURE FOR 1/4-28 CAP SCREWS

NOTE: This procedure can only be used with1/4-28 cap screws.

Do not use cap screws with any other typethread or new SCR will be damaged.

Do not over tighten cap screws. The leaf springwill apply the required clamping force to theSCR.

1. Do not turn the nuts. While holding the nutsstationary, turn the cap screws only with thefollowing procedure.

2. Tighten first cap screw 1/4 turn.

3. Tighten second cap screw 1/2 turn.



6. Tighten first cap screw 1/4 turn. Stop.

7. Assembly now has the proper clampingforce.

8. Perform the Active SCR Test.

CLAMPING PROCEDUREFOR 1/4-20 CAP SCREWS








5. Tighten second cap screw 1/4 turn. STOP.



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LINCOLN ®

ELECTRIC

IDEALARC DC-400


PROCEDURE FOR THE5/8 INCH WIDE SPRING

1. Place a piece of sleeving around each capscrew.

2. Insert cap screws through the leaf spring.The leaf spring is flat so the orientation of theleaf spring does not matter.

3. Place the steel pressure pad in the housingwith the 1/8 inch wide standoff facing up.See Figure F.23.

4. Insert cap screws and leaf spring into plastichousing being sure that the steel pressurepad remains in position. Pressing on the capscrew heads should produce a rocking actionof the spring in its housing.

5. Insert the clamp assembly through the heatsinks. Install nuts. Tighten the clamp nutsequally on the cap screws until finger tight.Be sure that the leaf spring is not cocked inthe housing. See Figure F.24. Heat sinksmay not be exactly as pictured.

6. Reinspect the SCR for proper seating.

FIGURE F.23 – HOUSING AND PRESSURE PAD FOR 5/8” WIDE LEAF SPRING

FIGURE F.24 – CLAMP ASSEMBLY

STEEL PRESSURE PAD

HOUSING

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

CLAMPING PROCEDURE FOR 1/4-28 CAP SCREWS













AFTER REPLACING THE SCRs

Follow the steps in the SCR/Diode RectifierRemoval and Replacement procedure toreassemble the machine.

CLAMPING PROCEDUREFOR 1/4-20 CAP SCREWS














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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

MOUNTING OF STUD TYPE DIODES TO ALUMINUMHEAT SINKS



DESCRIPTION

The following procedure will aid the technician in mounting stud type diodes to the aluminumheat sinks on the DC-400.

MATERIALS NEEDED

5/16” Nut driver1/2” Open end wrenchLincoln E1868 (Dow Corning 340) Heat Sink Compuond“Slip” type torque wrenchNo. 000 fine steel wool

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

PROCEDURE



3. Loosen the appropriate diode nut andremove the diode that is to be replaced.

4. Clean the area on the heat sink around thediode mounting surface using a putty knifeor similar tool. DO NOT SCRATCH THEDIODE MOUNTING SURFACE.

5. Polish each heat sink’s mounting surfaceusing No. 000 fine steel wool. Wipe the sur-face clean with a lint-free cloth or papertowel.

6. Inspect the mounting surfaces of each newdiode. Remove all burrs and wipe clean. Donot use steel wool or any abrasive cleanseron the diode mounting surface.

7. Apply a thin (0.003” to 0.007”) uniform layerof E1868 (Dow Corning 340) heat sink com-pound to the heat sink mounting surface.

a. Do not apply compound to the diodestud or mounting threads.

b. The diode threads must be clean andfree of defects so that the nut can be fin-ger tightened before applying torque. A“slip” type torque wrench must be usedto tighten the diode nut.

8. Tighten the diode nuts to the specificationsin the following table.

a. Start the nuts for diodes with steel studsby hand and then torque them accord-ing to the following table.

b. Run the nuts for diodes with copperstuds on all the way by hand then torquethem according to the following table.

c. Turn the nuts a minimum of 1/2 turnmore while torquing.


DIODE STUD FOOT- INCH-SIZE POUNDS POUNDS

3/4-16 25-27 300-3243/8-24 10±.5 125+0/-51/4-28 22-25

MOUNTING OF STUD TYPE DIODES TO ALUMINUMHEAT SINKS (continued)

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

WARNING

MAIN TRANSFORMER REMOVAL AND REPLACEMENT



DESCRIPTION

The following procedure will aid the technician in removing the main transformer for mainte-nance or replacement.

MATERIALS NEEDED

5/16” Nut driver9/16” Socket wrench9/16” Box end wrench1/2” Socket wrench1/2” Box end wrench3/8” Nut driver or socket wrench9/16” Deep well socket wrench

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

REMOVAL OF LIFT BAIL



3. Remove the two fiber baffles from the leftand right sides of the lift bail adjacent to themain transformer. See Figure F.25.

4. Remove the fiber baffle from the left side ofthe choke.

5. Remove the two leads from resistor R1 (15 ohms, 100 watts).

6. Remove the positive capacitor strap fromthe output shunt.

7. Remove the negative capacitor strap fromthe mode selector switch.

8. Remove lead #204 from resistor R2 (40 ohms, 50 watts) located on case back.

9. Remove leads #204 and #227 from resistorR3 (7.5 ohms, 100 watts) located on caseback.

10. Remove the sheet metal screw that holdsthe capacitor bank assembly to the caseback. (This should enable the capacitorbank to be removed with the lift bail assem-bly.)

11. Using the 9/16” socket wrench, remove thefour bolts (left and right) mounting the lift bailto the transformer top and bottom irons.

12. Using the 9/16” socket wrench, remove thefour bolts, flat washers, and lock washersmounting the lift bail assembly to the base ofthe machine.

The transformer and choke assembly is nowloose and free to slide or “tip” on the base of themachine.

13. Remove the lift bail by lifting straight up andclear from the machine.

MAIN TRANSFORMER REMOVAL & REPLACEMENT (continued)

WARNING

FIGURE F.25 – LIFT BAIL REMOVAL

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

FIGURE F.26 – CHOKE REMOVAL


REMOVAL OF CHOKE AND TOPIRON ASSEMBLY

1. Remove the two (left and right) glastic stiffen-ers connecting the negative rectifier plateand choke assembly to the main transformerthru-bolts. See Figure F.26.

2. Remove the top and center choke leads fromthe mode selector switch.

3. Remove the bottom choke lead from the neg-ative rectifier plate.

4. Label and cut or desolder the choke controlcoil leads that are soldered to the arc controlswitch. Cut any necessary cable ties.

5. Using the 9/16” deep well socket wrench,remove the four thru-bolts that clamp the top“E” iron and choke assembly to the bottom“E” iron. NOTE: for easier reassembly, cleanthe threads.

6. Using a hoist, carefully lift the choke and topiron assembly out and clear of the trans-former coils.

NOTE: The coils may be “stuck” to the top ironand may require some careful prying todislodge them. Depending upon whichcoil(s) are to be replaced, it may beadvantageous to remove some of the“stuck” coils with the top iron.

7. The leads from the coils that are to beremoved and/or replaced must be discon-nected. See the Wiring Diagram.

When aluminum leads are re-connected, apply athin layer of Dow Corning 340 Heat SinkCompound (Lincoln E1868) to mating surfaces.

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LINCOLN ®

ELECTRIC

IDEALARC DC-400

FIGURE F.27 – EPOXY MIX APPLICATION AREAS


REASSEMBLY OF TRANSFORMERCOILS

NOTE: The following procedure describes acomplete replacement of all primary and sec-ondary transformer coils. Adapt the procedurefor the specific coils you may be replacing.

1. Apply a coating of Lincoln Electric E2547Epoxy Mix along both sides of the bottomiron (lamination) assembly in the areas wherethe coil sides will be mounted. Coat theareas no closer than .38 inches from the topedge of the iron. See Figure F.27, arrows. Besure that none of the epoxy drips onto thetop of the iron assembly where it will meet thetop assembly.

3. Install the bottom primary coils, one on each of thethree legs of the bottom iron assembly. The coilsmust be in correct position (left, center, right).Place the coils so that the leads come out at theback of the machine. See Figure F.28 for properpositioning.

4. Place insulation (Lincoln Electric part numberS20728) on top of each of the three primary coils.The longer side of the insulation should be placedtoward the front of the machine. See Figure F.29for the location of this insulation

5. Place the three secondary coils on top of the insu-lation installed in Step 4. The leads should comeout at the front of the machine with the short leadson top. See F.28 for proper positioning.

6. Insert shims (Lincoln Electric part numberCI001250 or CI000317) between the secondarycoil sides and the iron assembly on either side ofthe legs. See Figure F.29.

7. Place insulation (Lincoln Electric part numberS20728) on top of each of the three secondarycoils. The longer side of the insulation should beplaced toward the front of the machine, where thesecondary start and finish leads come out. SeeFigure F.29.

8. Install the three top primary coils, noting which isright, left, and center. Leads should come out atthe back of the machine. See Figure F.28 for prop-er positioning. The coils must be in correct position(left, center, right).

9. Install the top iron (lamination) and choke assem-bly. With the 9/16” deep well socket wrench,reassemble the four thru-bolts that clamp the top“E” iron to the bottom “E” iron. Lightly tap on thetop of the iron with a hammer before tightening.Tighten the nuts and thru bolts to 19-25 lb-ft.


LINCOLN ®

ELECTRIC

IDEALARC DC-400Ret

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FIGURE F.28 – COIL LEAD PLACEMENT

FIGURE F.29 – COIL INSULATION


PRIMARY COIL LEADS

MACHINE FRONT

SECONDARY COIL LEADS

PRIMARY COILS

TOP LEFT TOP CENTER TOP RIGHT

PRIMARY COIL (BOTTOM)

SECONDARY COIL ASSEMBLYINSULATION

SHIMS

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LINCOLN ®

ELECTRIC

IDEALARC DC-400


10. Mount the primary thermostat to the leadend coil nose. See Figure F.30. Place asmall amount of Lincoln Electric E1603Epoxy between the coil nose and the coilinsulation and between the insulation andthe thermostat. Hold the thermostat inplace with E2381 (.375” wide) tape. If nec-essary, after assembly protect the thermo-stat terminals with E2547 terminal boots.

11. If necessary, trim off excess secondary leadstickout and TIG weld the leads together.See Figure F.31.

FIGURE F.30 – PRIMARY THERMOSTAT LOCATION

FIGURE F.31 – SECONDARY LEAD TRIM AND WELD DETAIL

TIG WELD

TOP VIEW

THERMOSTAT

FRONT VIEWINSULATION

REASSEMBLING THE MAINTRANSFORMER INTO THE MACHINE

NOTE: The following procedure assumes you havecompletely reassembled the transformer coilsas described in the procedure above. Thelower iron has remained in place in themachine. See Figures F.25 and F.26.

1. Resolder the choke control coil leads to the arccontrol switch.

2. Attach the bottom choke lead to the negative recti-fier plate.

3. Attach the top and center choke leads to the modeselector switch.

REASSEMBLE THE LIFT BAIL

1. Carefully position the lift bail onto the machinebase. Using the 9/16” socket wrench, attach thelift bail to the base of the machine with four bolts,flat washers, and lock washers.

2. Using the 9/16” socket wrench, attach the lift bailto the transformer top and bottom irons with fourbolts.

3. Attach the sheet metal screw that holds thecapacitor bank assembly to the case back.

4. Connect leads #204 and #227 to resistor R3.

5. Connect lead #204 to resistor R2.

6. Connect the negative capacitor strap to the modeselector switch.

7. Connect the positive capacitor strap to the outputshunt.

8. Attach the two leads to resistor R1.

9. Attach the fiber baffle to the left side of the choke.

10. Attach the two fiber baffles to the left and rightsides of the lift bail, adjacent to the main trans-former.

11. Install the machine case top and sides.


LINCOLN ®

ELECTRIC

IDEALARC DC-400Ret

urn

to S

ectio

n T

OC

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urn

to S

ectio

n T

OC

Ret

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to S

ectio

n T

OC

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to S

ectio

n T

OC

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urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

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urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC


Ret

urn

to S

ectio

n T

OC

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urn

to S

ectio

n T

OC

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urn

to S

ectio

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OC

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urn

to S

ectio

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OC

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urn

to M

aste

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OC

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to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC


LINCOLN ®

ELECTRIC

IDEALARC DC-400

RETEST AFTER REPAIRRetest a machine:

• If it is rejected under test for any reason that requires you to remove any mechanical part which could affect themachine’s electrical characteristics. OR

• If you repair or replace any electrical components.

INPUT IDLE AMPS AND WATTS

Input volts/Phase/Hertz Maximum Idle Amps Maximum Idle KW200/3/60 10.9 1.2208/3/60 10.5 1.2220/3/60 9.9 1.2230/3/60 9.5 1.2380/3/60 5.8 1.2400/3/60 5.5 1.2415/3/60 5.3 1.2440/3/60 5.0 1.2460/3/60 4.8 1.2500/3/60 4.4 1.2575/3/60 3.8 1.2

200/3/50 19.8 1.3220/3/50 18.0 1.3230/3/50 17.2 1.3380/3/50 10.4 1.3400/3/50 9.9 1.3415/3/50 9.5 1.3440/3/50 9.0 1.3500/3/50 7.9 1.3

OPEN CIRCUIT VOLTAGES

Mode Input Hertz Open Circuit VoltsConstant Current 60 54/58Constant Current 50 51/55

Constant Voltage 60 42.5/46.5(FCAW/GMAW) 50 42.5/46.5

Constant Voltage 60 43.5/47.5(SUB ARC) 50 43.5/47.5

Auxiliary Output (#31-#32) 60 114/124Auxiliary Output (#31-#32) 50 109/119

Auxiliary Output (#41-#42) 60 43.8/47.5Auxiliary Output (#41-#42) 50 42.0/45.6

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OC

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to S

ectio

n T

OC

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ectio

n T

OC

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to M

aste

r T

OC

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to M

aste

r T

OC

Ret

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to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC


LINCOLN ®

ELECTRIC

IDEALARC DC-400

RETEST AFTER REPAIR (continued)

MAXIMUM ACCEPTABLE OUTPUT VOLTAGE-AT MINIMUM OUPUT SETTINGS

Mode Control Settings LoadConstant Current Output Control and Arc Force Under 70 Amps @ 0 to 3 Volts

Control at Minimum

Constant Voltage Output Control at Minimum 120 Amps @ 6 to 12 Volts(FCAW/GMAW)

MINIMUM ACCEPTABLE OUTPUT VOLTAGE-AT MAXIMUM OUTPUT SETTINGS

Mode Control Settings LoadConstant Current Output Control at Maximum 525 Amps @ 41.5 Volts (Min)

Constant Voltage Output Control at Maximum 525 Amps @ 41.5 Volts (Min)(FCAW/GMAW)

Constant Voltage Output Control at Maximum 525 Amps @ 41.5 Volts (Min)(SUB ARC)

TABLE OF CONTENTS- ELECTRICAL DIAGRAMS SECTION -

IDEALARC DC400

Electrical Diagram Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section G

Wiring Diagram (Codes 9847, 9848) . . . . . . . . . . . . . . . . . . . . . . . . . . . G-2Wiring Diagram (Code 9850) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-3Control PC Board (G2588) Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-4Starting PC Board (M14520) Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . G-5Snubber PC Board (M15370) Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . G-6Control PC Board (G2588) Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . G-7Starting PC Board (M14520) Schematic . . . . . . . . . . . . . . . . . . . . . . . . . G-8Snubber PC Board (M15370) Schematic . . . . . . . . . . . . . . . . . . . . . . . . G-9

G-1G-1R

etur

n to

Mas

ter

TO

CR

etur

n to

Mas

ter

TO

CR

etur

n to

Mas

ter

TO

CR

etur

n to

Mas

ter

TO

C

NOTES

IDEALARC DC400

Ret

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to S

ectio

n T

OC

Ret

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to S

ectio

n T

OC

Ret

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to S

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OC

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r T

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Ret

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aste

r T

OC

Ret

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aste

r T

OC

G-2ELECTRICAL DIAGRAMS

IDEALARC DC400

Wiring Diagram (Codes 9847, 9848)

L

9106

12-9

-94F

H2

H3

H4

ELEC

TRIC

AL

SYM

BO

LS P

ER

11

243

1

6 P

IN4

PIN

8 P

IN12

PIN

J6J3

J2C

ON

NEC

TOR

CA

VITY

NU

MB

ERIN

G S

EQU

ENC

E(C

OM

PO

NEN

T S

IDE

OF

P.C

.B

OA

RD

)

NO

TES

225

42

3132

7576

77

225

TS1

TS2

C6

.004

7MFD

/140

0V

10K

/

2WA

RC

FO

RC

E C

ON

TRO

LS

4C

AC

TUA

TED

IN C

C O

NLY

S4D

AC

TUA

TED

218

204

208

209

R5

228

204

219

217

204

GR

EEN

216

CH

OK

EO

UTP

UT

L1

MO

DE

SW

ITC

H

S4A

CC CC

S4B

F3

21

S21

6

R1

219

15

/10

0W

AR

C C

ON

TRO

L

CO

NTR

OL

BO

AR

D

1 2 34 5 6

J6

STA

RTI

NG

BO

AR

DP

622

5VM

206

231

+ + --

224

224

7521

1

R4

10K

/

2WO

UTP

UT

CO

NTR

OL

S2

OU

TPU

T C

ON

TRO

LS

WIT

CH

32A

7621

221

121

377

S3

SW

ITC

H

32 4

SW

ITC

HM

ULT

I-P

RO

CES

SO

PTI

ON

AL + -

WO

RK

ELEC

TRO

DE

42

TO N

EG.

TER

M.

TO P

OS

.TE

RM

.

232 P

ILO

TLI

GH

T

SW

ITC

HP

OW

ERS

1

225

P2

209

214

217

204

206

206

208

1 2 3 4 5 6 7 8 9

J2

10 11 1220

520

521

27521

3

J1

8765432120

120

220

320

4 4

P1

12

34

J3

P3

AU

XILI

AR

Y

10 7 4 1 16

P5

1 2 3 4 5 6 7 8

J5 SN

UB

BER

B

OA

RD

204

GR

EEN

224

225

223

222

221

220

D1

D2

D3

SC

R1

SC

R2

D4

204

G3

G2

G1

204

204

205

206

216

215

CR

3S

HU

NT

SW

ITC

HR

EED

204

REC

TIFI

ERA

SS

EMB

LYC

1C

2C

3C

4C

5

+ + + + +

31,0

00M

FD50

V EA

CH

254

204

0.5

/50

W

0.5

/50

W10

AS

LOW

BLO

W

R7R8

F2

OP

TIO

NT1

MA

INTR

AN

SFO

RM

ER

CA

PA

CIT

OR

DIS

CH

AR

GE

REL

AY

CR

4

4231

231

115V X2

X1

232

3132A

CO

NTA

CTO

RC

R1

X1 233

TO S

UP

PLY

LIN

ESH4

4569 8 7

1112

21V

18369

SS

S

X2 S

ECX1

SEC

X3 S

EC

1725 8

201

FAN

MO

TOR

H1 C

ON

NEC

T O

R

INP

UT

CO

NN

ECTI

ON

DIS

CH

AR

GE

CA

PA

CIT

OR

+-

S5

SC

R3

202

203

1 5

6 7 8

31 32 228

215

218

N.C

.

N.O

.

N.C

.

N.O

.

MET

ERS

(SH

OW

N C

ON

NEC

TED

FO

R 2

20 V

.)

TO G

RO

UN

DP

ER N

ATI

ON

AL

ELEC

TRIC

AL

CO

DE

H2

H3

113 2 1

CO

NTA

CTO

RC

R1

X1

233

TO S

UP

PLY

LIN

ES

H1

(SH

OW

N C

ON

NEC

TED

REC

ON

NEC

T P

AN

EL

H2

H3

TO P

RIM

AR

Y C

OIL

SC

OIL

STO

PR

IMA

RY

232

CO

NTA

CTO

RC

R1

X1

233

TO S

UP

PLY

LIN

ES

45 6

9 8 7

H13 2 1

H2

H3

232

N.B

.22

0/38

0/44

0 VO

LTA

GE

N.A

.

380/

500

V.

N.B

.

N.A

.

H2

H3

H4

E153

7

15 64

32

1 2 3 4 5 6

2 3 42 3 4

7 8 9 10 11 12

6 P

IN4

PIN

12 P

INJ6

J3J2

CO

NN

ECTO

R C

AVI

TYN

UM

BER

ING

SEQ

UEN

CE

(CO

MP

ON

ENT

SID

E O

F P

.C.

BO

AR

D)

42

3132

7576

77

TS2

218

204

208

209

R5

21421

8

234

217

216

CH

OK

EO

UTP

UT

L1

FRO

NT

GA

NG

S4A

CC CC

S4B

F3

21

S21

6

234

SW

ITC

H

CO

NTR

OL

BO

AR

D

1 2 34 5 6

J6

STA

RTI

NG

BO

AR

DP

622

5

AM

206

231

+ + --

224

224

210

R4

OU

TPU

TC

ON

TRO

L

7621

221

021

121

377

+ -

WO

RK

ELEC

TRO

DE

42

TO T

ERM

.S

TRIP

232 P

ILO

TLI

GH

T

SW

ITC

HP

OW

ERS

1

225

209

214

217

204

206

206

208

1 2 3 4 5 6 7 8 9

J2

10 11 1220

520

521

27521

3

J1

8765432120

120

220

320

422

522

0

12

34

J3

CO

ILSP

RIM

AR

YTO

P10 7 4 1

BO

TTO

MP

RIM

AR

Y

P5

1 2 3 4 5 6 7 8

J5 SN

UB

BER

B

OA

RD

204

GR

EEN

224

225

223

222

221

220

D1

D2

D3

SC

R1

SC

R2

D4

204

G3

G2

G1

204

204

205

206

216

215

CR

3S

HU

NT

SW

ITC

HR

EED

REC

TIFI

ERA

SS

EMB

LYC

1C

2C

3C

4

+ + + + +

31,0

00M

FD50

V EA

CH

254

204

0.5

/50

W

0.5

/50

W10

AS

LOW

BLO

W

R7R8

F2

OP

TIO

N

CA

PA

CIT

OR

DIS

CH

AR

GE

REL

AY

CR

4

4231

231

115V X2

204

115V

1112 369

X2 S

ECX1

SEC

X3 S

EC

25 8

201

INS

ULA

TE A

S

T2 C

ON

TRO

L

DIA

GR

AM

DIS

CH

AR

GE

CA

PA

CIT

OR

+-

S5

SC

R3

202

203

16 7 8

32 228

215

218

10 12FL

EX L

EAD

JUM

PER

230/

400

VOLT

AG

E

T0 P

RIM

AR

Y C

OIL

S

11 10 12

W V u

L1L2

L3

18 17 16

3 2 1

W V U

L1L2

L3L1

L2L3 W V U

41

42

422

4141

SEC

ON

DA

RY

PR

IMA

RY

CIR

CU

ITB

REA

KER

42A

42V

S

241

115V

S

21V

3141 21

7576

7742

32

N.A

.

42

51

5250

2AC

IRC

UIT

BR

EAK

ER

S22

0VN

.C. 41

9 10

2

240

Y42

LIG

HT

MIN

. IN

D.

(5)

MA

X. IN

D.

(1)

N.A

. C

IRC

UIT

RY

PR

ESEN

T O

NC

AP

AC

ITO

R D

ISC

HA

RG

EO

NLY

.

N.B

. TA

PE

UP

SEP

AR

ATE

LYTO

PR

OVI

DE

AT

LEA

ST

600

V IN

SU

LATI

ON

.

N.C

. 22

0V W

IND

ING

, P

LUG

50/6

0 H

ERTZ

WEL

DER

.

10A

CIR

CU

ITB

REA

KER

W23

323

3

10A

MP

THER

MO

STA

TTH

ERM

OS

TAT

N.B

.

N.D

.

21V

N.D

. 31

AN

D 3

2 A

RE

NO

T P

RES

ENT

ON

EU

RO

PEA

N

MO

DEL

S.

TER

MIN

ALS

2

CO

NTA

CTO

RC

R1

UVW

X1

233

4569 8 7

H13 2 1

H2

H3

CO

ILS

TO P

RIM

AR

Y

232

CO

NTA

CTO

RC

R1

UVW

X1

233

TO S

UP

PLY

LIN

ES

H13 2 1

232

H2

H3

N.B

.

N.B

.

L1L2

L3TO S

UP

PLY

LIN

ES

L1L2

L3

REC

ON

NEC

T P

AN

EL

123

FOR

380

V.)

REC

ON

NEC

T P

AN

ELR

ECO

NN

ECT

PA

NEL

DO

ES N

OT

AP

PEA

R O

NTH

IS C

ON

NEC

TIO

N

H1

15 6 7 8

15 6 7 8

10 P

INJ5

J1109

AN

D C

IRC

UIT

BR

EAK

ER

AR

E P

RES

ENT

ON

LY O

N

STU

DG

RO

UN

DIN

G

LEA

D N

OT

PR

ESEN

T W

ITH

DIO

DE

OP

TIO

N

DIO

DE

OP

TIO

N

N.E

.

N.E

. C

IRC

UIT

RY

PR

ESEN

T O

ND

IOD

E O

PTI

ON

ON

LY.

THER

MA

LP

RO

TEC

TIO

N

TRA

NS

FOR

MER

SH

OW

N O

N

21224

VOLT

MET

ERS

WIT

CH

S6

21

225

+ R3 R2

227

204

R3 R2

7.5

/10

0W

40

/50W

OU

TPU

T

CV-

FCA

W/G

MA

WC

V-S

UB

AR

C

CV-

FCA

W/G

MA

W

CV-

SU

B A

RC

ON

LYC

V-FC

AW

/GM

AW

220

/380

/440

V A

ND

230/

400V

MA

CH

INES

TO G

RO

UN

DP

ER N

ATI

ON

AL

(SH

OW

N C

ON

NEC

TED

F

OR

230

V.)

TO G

RO

UN

DP

ER N

ATI

ON

AL

TO G

RO

UN

DP

ER N

ATI

ON

AL

DUAL

& S

INGL

E VO

LTAG

EUN

DER

346

VOLT

S(S

HOW

N CO

NNEC

TED

FOR

LOW

VOL

TAGE

)

CO

DE

SIN

GLE

VO

LTA

GE

OVE

R 3

45 V

OLT

STO

GR

OU

ND

PER

NA

TIO

NA

L EL

ECTR

ICA

L

ELEC

TRIC

AL

CO

DE

ELEC

TRIC

AL

CO

DE

ELEC

TRIC

AL

CO

DE

205

206

G-2R

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

C

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. The wiring diagram specific to your code is pasted inside one of the enclosure panels of your machine.


IDEALARC DC400

Wiring Diagram (Code 9850)

L

9107

13 14 15 16 17 18

H2

H3

H4

ELEC

TRIC

AL

SYM

BO

LS P

ERE1

537

CO

NN

ECTO

R C

AVI

TYN

UM

BER

ING

SEQ

UEN

CE

(CO

MP

ON

ENT

SID

E O

F P

.C.

BO

AR

D)

NO

TES

N.A

.C

IRC

UIT

RY

PR

ESEN

T O

NC

AP

AC

ITO

R D

ISC

HA

RG

EO

NLY

.

TO P

RO

VID

E A

T LE

AS

T60

0 V

INS

ULA

TIO

N.

CO

NTR

OL

BO

AR

D

P6

206

205

VM AM

206

231

+ + --

232 P

ILO

TLI

GH

T

SW

ITC

HP

OW

ERS

1

225

225

P2

209

214

217

204

206

206

208

1 2 3 4 5 6 7 8 9

J2

10 11 1220

520

521

27521

3

J1

8765432120

120

220

320

422

522

0 4

P1

12

34

J3

P3

AU

XILI

AR

YC

OIL

S

PR

IMA

RY

TOP

10 7 4 1

BO

TTO

MP

RIM

AR

Y

16

P5

1 2 3 4 5 6 7 8

J5 SN

UB

BER

B

OA

RD

204

GR

EEN

224

225

223

222

221

220

D1

D2

D3

SC

R1

SC

R2

D4

204

G3

G2

G1

204

204

205

206

216

215

CR

3S

HU

NT

SW

ITC

HR

EED

204

REC

TIFI

ERA

SS

EMB

LYC

1C

2C

3C

4C

5

+ + + + +

31,0

00 M

FD50

V EA

CH

254

204

0.5

/50

W

0.5

/50

W10

AS

LOW

BLO

W

R7R8

F2

OP

TIO

N

T1 M

AIN

TRA

NS

FOR

MER

CA

PA

CIT

OR

DIS

CH

AR

GE

REL

AY

CR

4

4231

231

115V X2X1

232

31 32A

204

CO

NTA

CTO

RC

R1

X1 233

H2

TO S

UP

PLY

LIN

ES

H3

H4

45 6

3 9 8 2 7 1

REC

ON

NEC

T P

AN

EL

230/

460/

575V

.

TO G

RO

UN

D P

ER N

ATI

ON

AL

ELEC

TRIC

AL

CO

DE

12 1836159

S

SS

X2 S

ECX1

SEC

X3 S

EC

172514820

1

FAN

MO

TOR

H1

CO

NN

ECT

OR

INS

ULA

TE A

SS

HO

WN

ON

INP

UT

CO

NN

ECTI

ON

DIA

GR

AM

DIS

CH

AR

GE

CA

PA

CIT

OR

+-

SC

R3

202

203

MET

ERS

TAP

E U

P S

EPA

RA

TELY

W U

41

42 42

2

41 41

10 A

MP

CIR

CU

IT

BR

EAK

ER

SEC

ON

DA

RY

PR

IMA

RY

THER

MO

STA

TS

42V

42A

S

21V

115V

S

21V

21V

41 242 Y

9 10

N.B

.

W23

323

3

LIG

HT

240

241

V

L1L2

L3

N.B

.

N.B

.

N.A

.

225

431

32

TS1

TS2

C6

.004

7MFD

/140

0V

10K

/

2W

218

204

208

209

R5

22820

4

219

217

204

GR

EEN

216

MO

DE

SW

ITC

H

S4A

CC CC

S4B

F3

21

S21

6

R1

219

15

/10

0W

AR

C C

ON

TRO

L

6

J6

STA

RTI

NG

BO

AR

D

224

224

7521

1

R4

10K

/

2WO

UTP

UT

CO

NTR

OL

S2

OU

TPU

T C

ON

TRO

LS

WIT

CH

7621

221

121

377

SW

ITC

HM

ULT

I-P

RO

CES

SO

PTI

ON

AL

+ -

WO

RK

ELEC

TRO

DE

2

TER

M.

TO P

OS

.TE

RM

.

S5

31 32 228

215

218

N.C

.

N.O

.

N.C

.

N.O

.

N.A

.275

7677

218

21421

8

234

204

216

CH

OK

EO

UTP

UT

L1

FRO

NT

GA

NG

CC CC

F3

21

S

234

219

SW

ITC

H1 2 34 5

J6

224

224

210

R4

CO

NTR

OL

210

+ -

4

TO T

ERM

.S

TRIP

TO N

EG.

S5

N.A

.

MIN

. IN

D.

(5)

MA

X. IN

D.

(1)

AR

C F

OR

CE

CO

NTR

OL

32A

S3

SW

ITC

H

32 4

3141 21

7576

7742

3242

10A

CIR

CU

ITB

REA

KER TE

RM

INA

LS2

OU

TPU

T

(SH

OW

N C

ON

NEC

TED

FO

R 2

30 V

.)

TO P

RIM

AR

Y C

OIL

S

11

243

1

6 P

IN4

PIN

8 P

IN12

PIN

J6J3

J2

1 5

6 7 81

5 64

32

1

6 P

IN4

PIN

12 P

INJ6

J3J2

16 7 8

15 6 7 8

15 6 7 8

10 P

INJ5

J1109

STU

DG

RO

UN

DIN

G

DIO

DE

OP

TIO

N

N.C

.

LEA

D N

OT

PR

ESEN

T W

ITH

DIO

DE

OP

TIO

N

CIR

CU

ITR

Y P

RES

ENT

ON

N.C

.D

IOD

E O

PTI

ON

.

THER

MA

L P

RO

TEC

TIO

N

T2C

ON

TRO

LTR

AN

SFO

RM

ER

12-9

-94F

225

S4C

A

CTU

ATE

DIN

CC

ON

LY

21224

VOLT

MET

ERS

WIT

CH

S6

21

R3 R2

227

204

R3 R2

7.5

/10

0W

40

/50W

CV-

FCA

W/G

MA

WC

V-S

UB

AR

C

CV-

FCA

W/G

MA

W

CV-

SU

B A

RC

S4D

AC

TUA

TED

ON

LYC

V-FC

AW

/GM

AW

13

225

2 3 4 5 6

7 8 9 10 11 12

2 3 42 3 4

G-3R

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

C

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. The wiring diagram specific to your code is pasted inside one of the enclosure panels of your machine.


IDEALARC DC400

Control PC Board (G2588) Layout

SH

T.

NO

.G

IDEA

LAR

C D

C-4

00

258

8-1

CO

NTR

OL

P.C

. B

OA

RD

AS

SEM

BLY

IDE

NTI

FIC

ATI

ON

PA

RT

No.

RE

Q'D

.IT

EM

C23

A E M

G

KB

F

C

R315

R38

R37

R65

R82

R83

R10

2

R36

R35

R

101

R64

R104

R63

R55

R66

R57

R59 R58

R139

R56

R127

R145

R144

R143

R94

R120

R12

6

R40

R45

R41

R

42

R74 R75

R73

R119

R129 R90

R121

R130 R131

R123

R46

R48

R47

R77

R72

R52 R76

R68

R54

R69 R53

R70 R97

R106

R12

2

R96

R51

R49

R50

R109

R107

R110

R10

8

R138

R10

0 R

125

R12

4 R

85

R98

R

99

R95

R44

R13

2

R80

R88

R13

4 R

135

R137

R89

R61 R60

R62

R128

R91

R142

R105

R103

R111

R156

R300

R301

R302

R303

R304

R305

C56

C59

C68

C67

C61 C60

C58

C57

C45

C31

C19

C34

C16

C18 C17

C30

C25

C38

C37

C36

C32

C22

C20

C15

C39

C35

C26

C33

C24

DZ4

DZ6

DZ8

D82

D52

D51

D49

D55

D50

D31

D64

D54

D23

D22 D29

D25

D34

D35

D33

D32

D60

D59

D24

D30

D26

D42

D41

D43

D28

D45

D44

D53

D27

D61

D47

D

40

D58

D57

D63

D56

D36

D37

D46

D48

D79

X3

X4 X1

X2

X6

R67

R71

R148

Q4 Q3

Q1

Q8

Q6

Q5

C14

C51

DZ7

R149

DC400 CONTROL

D

N

J I H

G2588-1

R328 R327 R326 R325 R324 R323 R322 R321 R320 R319 R318 R317 R316

R31

4 R

313

R31

2

R15

2

R153

R118

R116

R147

R6

R13

R

87

R34

R5

R

12

R86

R33

R4

R11

R

10

R32

R19

R16

R22

R8

R18

R15

R21

R7

R17

R14

R31

R25

R30

R24

R29

R23

R14

0

R11

5

R93

R14

6

R20

R

306

R30

7

R30

8

R30

9

R31

0

R9

R31

1

C12

C11

C10

C9

C8

C7

C6 C5

C4

C44

C41

C3 C2

C1

C43

C40

DZ1

2

DZ3

DZ2

DZ1

DZ5

D70

D69

D68

D21

D20

D19

D73

D71

D72

D81

D80

D10

D77

D75

D78

D62

D74

D65

D66

D67

D18

D3

D17

D2

D16

D6

D9

D15

D5

D8

D14

D4

D7

D13

D12

D11

D76

D1

DZ1

4

DZ1

0

DZ9

DZ1

3

X7

J1 J2 J3

OCI1

R154 R155

R3

R2

R1

R117

R28 R27 R26

R81

R78 R79

R151

R114

R112

R113

SCR3 SCR2 SCR1

Q2

X5

QU3 QU1 QU2

R14

1

R150

G-4R

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

C

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

NOTE: Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are notavailable from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may resultin danger to the Machine Operator or Technician. Improper PC board repairs could result in damage to the machine.


IDEALARC DC400

Starting PC Board (M14520) Layout

IDENTIFICATIONPART NO. REQ'DITEM

C1D1, D2D3, D4, D5, D6, D7R1, R2R3, R5R4R6

SCR2SCR1

TP1SBS1

TP2

11

111

12522

11

S13490-72

S15161-19S19400-1001

S19400-1501

T12199-1T12199-2

S20630-1T13640-12T13640-18

T14648-9

T14649-4

T14805-1

50/50

4A, 400V SCR

1.5K 1/4W

1N4007

38J160J

5W/2500 OHM RESISTOR

100 10W

SCR HEAT SINK AS'BLYSILICON BILATERAL SWITCH

1N4004

1K 1/4W

G-5R

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

C

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC



IDEALARC DC400

Snubber PC Board (M15370) Layout

ITEM PART NO.REQD DESCRIPTIONC1,C2,C3 3

23321

R1,R2,R3C4,C5

TP1,TP2,TP3TP4,TP5TP6

T11577-68

T12733-10T13640-12

T13640-16T13640-18

T11577-46.68/400.05/600

10 2W38J160J80J

G-6R

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

C

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC



IDEALARC DC400

Control PC Board (G2588) Schematic

1400V.0047C51

RF

+15V

-10V

+15V +15V

10K

R85

1.50K

R301

50V4C33

1N4004D55

475K

R128

1N4004D57

1.00M

R80

1N4004D56

100K

R59-7.5V

X28

10

9475K

R99

10K

R123

+15V

1N4004D59

VOLTAGE BUFFERRECTIFIER BRIDGE

+15V

1N4004D41

1.820V

C32 1N4004D60

100

R126

1N4004D42 1N4004

D61

10K

R98

2N4857Q1

1N4004D40

1W15VDZ6

1.820V

C15

102K

R100

X27

5

6

61.9K

R122

1.50K

R97

13.7K

R300

13.7K

R96

X314

13

12

-10V

SWITCHCURRENT

PROTECTIONOVER-VOLTAGECAPACITOR

82.5K

R132

100

R127

100K

R57

X41

2

3

2.21K

R50

4.735V

C44

R32

8

R321

R32

0

R319

R318

R316

R317

R32

2

100K

R153

10W160

R151

J17

R32

7

1W6.2VDZ12

R32

3

R32

4

1N4004D77

1N4004D76

1N4004D78

R32

6

R32

5

41

NOTES :

NOT SHOW THE EXACT COMPONENTS OR CIRCUITRY OF CONTROLS HAVING A COMMON CODEWITHOUT AFFECTING THE INTERCHANGEABILITY OF A COMPLETE BOARD, THIS DIAGRAM MAY

NUMBER.

N.A. SINCE COMPONENTS OR CIRCUITRY ON A PRINTED CIRCUIT BOARD MAY CHANGE

FILE: G2586-1BD

C

-7.5V

+15V

+15V

100K

R42

-10V

10K

R138

15W1.5K

R149

1N4004D25

475K

R131

X114

12

13

100

R152

J21X1

8

10

9

1N4004D30

10K

R48

1N4004D75

5W15V

DZ13

1N4004D26

CNY17-3OCI1

42

1

6

5

1N4004D29

J24

22.1K

R130

-10V

+15V

ARC FORCECONTROL

MODE BUFFER

ARC FORCE AMP

POT.

204

209

10K

10K

R46

CC LOW VOLTAGE

CC MAXOUTPUT

STABILIZER

208

15W1.5K

R150

10K

R47

47.5K

R111

1.50K

R30

4

OUTPUT10K

CONTROLPOT.

50V.022C19

10K

CW

R71

CW

10KR67

MODE INVERTER

75

10K

R68

-7.5V

-7.5V

+15V

-10V

50V.022C18

RF

J210

-10V

+15V

+15V

CV MAX

MIN. OUTPUT BUFFER

OUTPUT

+ t56

R781N4004D34

212

213

BUFFER

MAX.OUTPUT

2N4857Q3

+ t56

R81

RF

100

R75X17

5

6

267K

R74

392KR73

J28

267K

R72

1N4004D35

RF

100K

R105

1.82K

R115

4.75KR93

100KR315

1.820V

C22

15.0K

R94

+15V

1N4004D62

1N4004D28

475K

R69

2N4857Q4

1N4004D27

5.1VDZ7

1.50K

R54

332K

R52

10K

R70

10K

R53

100K

R51

100K

R49

750

R30

5

267R76

750

R77

1N4004D33

J29

50V.022C17

1N4004D32

+ t56

R79

X11

2

3

1N4004D13

LM224

X4

4

11

1N4004D16

102K

R119

J31

50V.022C10

J32

J34

1N4004D10

G1

+15V

EARTH GROUND CONNECTION

COMMON CONNECTION

.022/50V

(UNLESS OTHERWISE SPECIFIED)

GENERAL INFORMATION

1A, 400VRESISTORS = Ohms (

(ELECTRICAL SYMBOLS PER E1537

1/4W

CONTROL BOARD SCHEMATICIDEALARC DC400

FRAME CONNECTIONSUPPLY

LABELS

POWER SUPPLY SOURCE POINT

G3

UNLESS OTHERWISE SPECIFIED)UNLESS OTHERWISE SPECIFIED)CAPACITORS = MFD

DIODES =

100K

R30

1N4004D18

562

R32

1N4004D15

562

R311

50K

CW

R28

50V.022C12

50V.022C9

562

R34

100K

R31

203

10K

R145

X48

10

9

10K

R144

1N4005D73

1N4005D71

GND

IN OUTX5

1N4005D70

1N4005D72

201

202

10W250

R148

RF

1W2.7

R155

15050VC43

5W17VDZ910K

R147 500

50V

C40

1W2.7

R154

31.6K

R118

1N4005D69

1N4005D68

2K

CW

R117

1N4004D22 10K

R142

1N4004D82

+

REF

-TL431

X7

1

6

8

10K

R91

10K

R64

10K

R116

1N4004D49

1N4004D48

5W10V

DZ10

1.00K

R63

-10V

A

+15V

M

50V.022C34

10K

R143

221K

R156

1N4005D19

10K

R140

J13

J12

4735V

C39

J11

1N4004D74

1N4005D21

1N4005D20

1N4004D23

5W1K

R141

D

2586 G

220

202

POWER UPOUTPUT CLAMP

201

203

J23

J16

LM224

X3

4

11

2.67K

R146

1N4004D79

LM224

X1

4

11

+15V

4.735V

C41

LM224

X2

4

11

50V.022C30

1N4004D63

1.00M

R66

50V4C24

15.0K

R134

68.1K

R124

475K

R62

50V.68C35

1N4004D64

33.2K

R65

22.1K

R95

15.0K

R90

10K

R83

1N4004D36

1N4004D50

15.0K

R139

1N4004D37

50V0.1C56

1N4004D47

475K

R89

X38

9

10X3

1

2

3

1N4004D31

CC CONTROL AMP

1N4004D52

X4

12

14

13

1N4004D46

221K

R135

1N4004D54

26.7K

R125

22.1K

R129

X37

5

6

RF

+15V

-10V

LIMITERCC CURRENT

C.V. CONTROL

START PRESET

LIMITERCV CURRENT

1.820V

C20

33.2K

R88

200V.33C23

100K

R137

2N4857Q8

4.735V

C36

1N4004D51

X21

3

2

2N4123Q5

26.7K

R44

1N4004D58

4.75K

R82

C59C58C68 C57

-10V

C67

200

R30

7

267

R24

267

R23

200

R30

6

B

1W15VDZ4

13.7K

R40

22513.7K

R108

100V.047C38

J211

100V.047C37

J212

J26

J25

13.7K

R303

475

R36

1N4004D45

C45

475

R35

J22

-10V

1N4004D44

13.7K

R30

2

1400V.0047C14

J192

240204

4

214

1N4004D24

100

R45

100K

R41

50V.022

C16

243

R312

1N4004D80

J110

243

R313

J14

5W24V

DZ14

1N4004D81

R316-R328=68.1k 1/4W

243

R314

J18

.22100V

C26

24.9

R38

475

R37

22.1K

R55

2.21KR58

33.2K

R102

RG1

REFRG2

X68

1

5

3

6

2

267K

R104

1N4004D53

1N4004D43475K

R106

.047100V

C25

5.62K R110

26.7K

R107

X214

13

12

332K

R101

1.50K

R109

1W30VDZ8

1.00M

R103

+15V

1.00K

R20

QU1

5W68

R114

202

1N4004D67

267

R25

200

R30

8

201

1/2W27

R3

1N4004D66

4.735V

C1

5W68

R112

1W15VDZ1

RF

J

I

H

N

4.735V

C2

1W15VDZ2

5W68

R113

1/2W27

R2

475

R10

1N4004D4

100K

R12

100V.15C5

4.75K

R18

400V4ASCR3

1N4004D2

1N4004D65

1/2W27

R1

D

G S

15A60V

Q2

1N4004D8

1N4004D7

267

R14

1W15V

DZ5

400V4ASCR1

1.00K

R21

2.67K

R4

1N4004D1

100K

R11

4.75K

R17

400V4ASCR2

QU2

267

R15

2.67K

R5

1N4004D5

2.67KR7

100V.15C4

475

R86

2.67KR8

267

R16

1.00K

R22

203

1N4004D3

475

R87

FIRING CIRCUIT

100K

R13

QU3

100V.15C6

4.75K

R19

1N4004D9

1N4004D6

1W15VDZ3

2.67KR9

4.735VC3

2.67K

R6

GSHT.

82

LAST NO. USED

68C-R-D-

NO.

328

2586

VOLTAGE NET

X6

AD620

7

4

50V.022C31

X47

5

6

51.1K

R120

C61

+15V

-7.5V

204

G2

33.2K

R121

C60

J33

1N4004D14

50K

CW

R27 562

R33

1N4004D11

562

R30

9

562

R310

100K

R29

50V.022C7

1N4004D17

50K

CW

R26

50V.022C11

50V.022C8

1N4004D12

206

205

CURRENT AMP

J27

+15V

J15

E

10K

R56

L

K

2N4857Q6

6.81K

R61

3.01K

R60

+15V

-10VRF

+15V

F

-7.5V

+15V

G

B3-11-94

G-7R

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

C

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC



IDEALARC DC400

Starting PC Board (M14520) Schematic

55A400V

SCR2

13

2

38J130VTP1

D5D4D3

1N4007D2

J64

4A400V

SCR1

1.00K

R5

1.00K

R3

1.50K

R4

5W2500

R1

SBS1

G

J6

2

10W100R

6

21

160J320VTP2

50V50C1

J6

6

J61 D7 D6

1N4007D1

5W2500

R2

J6

3

19686S

START

S

= COMMON CONNECTION

IDEALARC DC400

ELECTRICAL SYMBOLS PER E1537

19686

218

32

31

228

SCHEMATIC

CAPACITORS = MFD/VOLTS

GENERAL INFORMATION

DIODES = 1 AMP/400 VOLT (UNLESS OTHERWISE SPECIFIED)OP AMPS = LM124 (UNLESS OTHERWISE SPECIFIED)

RESISTORS = OHMS,1/4 WATT (UNLESS OTHERWISE SPECIFIED)

216215

J6

5

7.5-9.0V

MT2 MT1

11-17-95G

G-8R

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

C

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC



IDEALARC DC400

Snubber PC Board (M15370) Schematic

38J130V

TP3

S

160J320VTP5

19687

225

19687

160J320VTP4600V

.05C4

600V.05C5

J5

8

J5

3

J5

2

J5

4

J5

7

J5

5

SNUBBER SCHEMATIC

J5

1

2W10

R3

J5

6

80J150VTP6

2W10

R2

2W10

R1

38J130V

TP2

ELECTRICAL SYMBOLS PER E1537GENERAL INFORMATION

CAPACITORS = MFD/VOLTSRESISTORS = OHMS,1/4 WATT (UNLESS OTHERWISE SPECIFIED)

38J130V

TP1

.068400V

C11

2.068400V

C21

2

DIODES = 1 AMP/400 VOLT (UNLESS OTHERWISE SPECIFIED)OP AMPS = LM124 (UNLESS OTHERWISE SPECIFIED)

= COMMON CONNECTION

224220223204 222221

S

.068400V

C3 1

2

MISC. USE3-8-91G

G-9R

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

CR

etur

n to

Sec

tion

TO

C

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC

Ret

urn

to M

aste

r T

OC


Documents

Lincoln Idealarc DC 400