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WELDING INDUSTRIES OF AUSTRALIA A DIVISION OF WELDING INDUSTRIES LTD
ACN 004 547 l l l
Head Office and International Sales
5 Allan Street, Melrose Park
South Australia, 5039
Telephone (08) 8276 6494 Facsimile (08) 8276 6327
OWNERS MANUAL
WELDMATIC TWO ROLL DRIVE
ENCLOSED WIREFEEDER
MODEL NO. W41-0, REV. B
12/98
QUALITY WELDING PRODUCTS, SYSTE#S AND SERVICE 4
Page 2 WELDMATIC W414 WtREFEEDER MANUAL
The information contained in this manual is set out to enable you to properly maintain your new equipment and ensure that you obtain maximum operating efficiency.
Please ensure that this information is kept in a safe place for ready reference when required at any future time.
When requesting spare parts, please quote the model and serial number of the machine and part number of the item required. All relevant numbers are shown in lists contained in this manual. Failure to supply this information may result in unnecessary delays in supplying the correct parts. SAFETY
Before this equipment is put into operation, the Safe Practices section at the back of the manual must be read completely. This will help to avoid possible injury due to misuse or improper welding applications. PLASTIC HANDLE
intended for carrying the machine by hand only.
manner.
Please note that the handle fitted to the WELDMATIC W41-Q WIREFEEDER is
DO NOT use this handle for suspending or mounting the machine in any other
CONTENTS
Sec.1 ................... Introduction .................................................... P.3 Sec.2 ................... Receiving ....................................................... P.3
Sec.4 ................... Wirefeeder Controls ...................................... P.4 Sec5 ................... Installation ..................................................... P.5 Sec.6 ................... General Maintenance .................................... P.6 Sec.7 ................... Wirefeeder Assembly .................................... P.8 Sec.8 ................... Service Information ........................................ P. 18 Sec.9 ................... Parts Lists ...................................................... P. 1 l Sec.10. ................ Safe Practices ............................................... P. 14
Sec.3 ................... Specifications ................................................ P.3
FIGURES
Fig.1 .................... Wirefeeder Controls ...................................... P.4 Fig.2 .................... Connection to Power Source ......................... P.5 Fig.3 .................... W41-0 Wirefeeder Assembly ......................... P.9 Fig.4 .................... Wirefeeder Circuit Diagram ........................... P.10 Fig.5 .................... Gun Cable Assembly ..................................... P. l 1 Fig.6 .................... Wire Drive Assembly ..................................... P.12 Fig.7 .................... Inter-Connecting Lead Kit .............................. P. 13
WELbMATiC W414 WIREFEEDER I_ MANUAL - Page 3
l, INTRODUCTION
Gas Metal Arc Welding (G.M.A.W.) is basically a simple welding process, where a consumable wire is fed by motor driven rollers to a welding gun and welding current is supplied from the wetding power source. The welding arc is struck between the work piece and the end of the wire, which melts into the weld pool. The arc and the weld pool are both shielded by gas flow from the gun, or in the case of ‘self shielded’ wires, by gases generated by the wire core,
The process is quite versatile in that by selecting the correct wire composition, diameter and shielding gas, it can be used for applications ranging from sheetmetal to heavy plate, and metals ranging from carbon steel to aluminium alloys.
The WELDMATIC W41-0 WIREFEEDER has been designed to feed a range of hard, soft, and flux-cored wires for the Gas Metal Arc Welding process. A compact motor with integral gear box is coupled to a two roll drive assembly forming the basic component of the wire feeder. The motor is controlled by an electronic speed control which ensures excellent speed regulation over the full torque range of the motor, with inherent compensation for supply voltage variations.
2. RECEIVING
Check the equipment received against the shipping invoice to make sure the shipment is complete and undamaged. If any damage has occurred in transit, please immediately notify your supplier.
The W41 -0 package contains; W41-0 Enclosed Wirefeeder.
H AM286-0/10 Inter-connecting lead kit, 10 metre. R (This) Owners Manual.
3. SPECIFICATIONS
SUPPLY VOLTAGE 30 volts AC, (from welding power source)
RATED SUPPLY CURRENT 5 Amps
FUSE RATING 5 Amps
PRE-GAS RANGE 0 - 1.2 seconds
POST-GAS RANGE Q - 2.5 seconds
BURNBACK RANGE 0 - 0.09 seconds
START SPEED Normal or Reduced (switchable)
DIMENSIONS L - 610mm, W - 200mm, H - 420mm
MASS 33Kg (including Lead Kit)
SPOOL SIZES 5Kg, 15Kg
WIRESPEED RANGE 0 - I 90 RPM (0 - 18 Metres per min.)
WIRE SIZE RANGE 0.9mm - 1.2mm diameter (solid wire) 1.2mm - l .6mm diameter (cored wire)
Page 4 WELDMATIC W41-0 WIREFEEDER MANUAL
4. WIREFEEDER CONTROLS
I €3
c
FIGURE l.
1. WIRE SPEED CONTROL
WIRE FEEDER CONTROL§
This control sets the speed of the wire drive motor within the range of 0 - I90 RPM, equivalent to 0 - 18 metres per minute of welding electrode wire. Rotate the control clockwise to increase the feed rate. 2. POWER ON INDICATOR
the power source is switched on. 3. SPOT TIME CONTROL
When operating the machine in Spot Weld mode, this control will vary the spot weld time. Rotating the dial clockwise will increase the spot weld time, in the range 0.5 - 2.5 seconds. If the Spot Weld mode is not required this feature can be turned off by rotating the control anti-clockwise until it 'clicks' into the minimum position. 4. INTERVAL CONTROL
When operating the machine in Cycle Arc mode this control sets the period between welds. The spot time control sets the welding period. Rotating the dial clockwise will increase the interval time, in the range 0.5 - 2.5 seconds. If the Cycle Arc mode is not required this feature can be turned off by rotating both controls fully anti- clockwise.
This indicator is illuminated when wirefeeder is connected to a power source and
5. PRE-GAS CONTROL This control sets the time period of gas flow before welding commences, and may
be adjusted from 0 - 1.2 seconds. 6. POST-GAS CONTROL
This control sets the time period of gas flow after welding ceases, and may be adjusted from 0 - 1.2 seconds. 7. BURNBACK CONTROL
released, and wirefeed ceases, and may be adjusted from Q - 0.7 seconds, 8. START SPEED SWITCH
NORMAL (up) is selected for immediate starts, as required for tacking, short welds, etc. REDUCED (down) is selected for softer starts, as required when welding aluminium, etc.
This control sets the time period that welding continues after the gun switch is
This switch controls the start up speed of the wirefeeder;
WELDMATIC W41-0 WIREFEEDER MANUAL Page 5
INSTALLATION
The WELDMATIC W41-0 WIRE FEEDER is supplied with a lead kit consisting of:
WELDING CABLE
WORK LEAD
CONTROL CABLE
GAS HOSE Connections are shown in Figure 2. Check all connections are firmly made to
ensure good electrical contact, and to eliminate gas and air leaks. Check that the wire guide and drive roller fitted is appropriate to the electrode wire
to be used. For optional, combinations, see Section 8. Standard wirefeeders are factory fitted with a W51-0/2 bottom roller, and plain top roller, which are suitable for both 0.9mm and 1.2mm diameter steel wire.
GAS CYLINDER & REGULATOR
’WORK‘ CLAMP
-‘--/F WELDING CABLE
CONTROL CABLE
FIGURE 2. CONNECTIONS TO POWER SOURCE
Paae 6 WELDMATIC W41-0 WIREFEEDER MANUAL
7. GENERAL MAINTENANCE
OPERATOR CHECKS
If the wire feeder motor will not turn when gun switch is operated and speed control is set to desired speed, check the following points;
l, Ensure that 30 Volts A.C. power is available at wirefeeder and Power Indicator is lit. Check fuse located on power source front panel (1 0 Amp) and check fuse located on wirefeeder printed circuit board (5 Amp).
2. Fault may be either in gun switch or the switch wires in the gun cable. Check connections to motor and visually check printed circuit board ensuring that all components, wiring and electrical connections are secure.
If wirefeeder fuses fail repeatedly while welding, check the following points;
l. Check tension of spool holder or wire reel brake. Reel or spool should only have sufficient pressure applied to prevent over run when motor stops.
2. Ensure feed roll pressure is only sufficient to push wire evenly. Excessive pressure can deform electrode wires.
3. Ensure wire feed liner is clean. Blow out or replace if necessary. 4. Ensure tip is free of obstructions, ream out if necessary. Replace tip when
5. Ensure wire is straight and free of buckles. 6. Ensure wire is free of rust, replace if necessary. 7. Ensure feed roll gear teeth are free of interfering material.
oversize.
WELDMATIC W41-0 WIREFEEDER MANUAL Page 7
FITTING THE GUN CABLE
The BERNARD BEXT2-4E31OAE gun cable is equipped with a 'Euro' wirefeeder connector which incorporates all required connection points to the gun cable for welding current, shielding gas and gun switch control.
To attach the gun cable to the wirefeeder mechanism, engage the mating parts of the male and female Euro connectors, then rotate the locking ring clockwise to firmly secure the connection.
FITTING THE CONSUMABLE WIRE
The quality of the consumable wire greatly affects how reliably a gas metal arc welder will operate. For best results when welding mild steel, we recommend quality WIA AUSTMIG ES6. Dirty, rusty or kinked wire will not feed smoothly through the gun cable and will cause erratic welding. Deposits from the wire will clog the gun cable liner requiring it to be replaced prematurely.
Place the spool of welding wire onto the spool holder. The location pin should mate with a hole provided on the wire spool body. Fit the spool retaining 'R' clip supplied. Check the adjustment of the spool brake, which should be set to prevent over run of the wire spool at the end of a weld, without unduly loading the wirefeed motor. The braking can be adjusted by the Nyloc nut using a 15/16" AF or 24mm socket wrench.
FEEDING THE CONSUMABLE WIRE
With reference to Figure 6, release the pressure fixing arm (1 1 ), and rotate the pressure arm (8) to the open position. The end of the welding wire can now be passed through the inlet guide, over the bottom driven roller, and into the output wire guide tube. Check that the drive roller groove is correct for the wire in use. The appropriate size is stamped on the visible side of the installed roller. Check also that the correct size contact tip is fitted at the gun end. Drive roller and tip details are available in Section 8 of this manual.
Return the pressure arm to the closed position and adjust the compression screw to provide sufficient clamping of the drive roll to achieve constant wirefeed. Do not over tighten.
With the machine energised, operate the GUN SWITCH to feed wire through the gun cable.
9 C W41-0 WIREFEEDER MANUAL
7. WELDMATtC W41 -0 WIREFEEDER
ITEM # PART # DESCRIPTION
1 ....................... W41 -1 O... ...................... Wirefeeder Control PCB 2 ....................... W4 l-20Y ...................... Base Panel 3 ....................... W4 1-21Y ...................... Front Panel 4 ....................... W39-13Y Back Panel 5 ....................... W39-14Y ..................... .Top/Side Panel 6.. ..................... W39-15Y ...................... Door Panel 7.. ..................... W39-16Y .................... ..Divider Panel 8.. ..................... W41 -31Y ...................... Bridge Piece 9.. ..................... W50-l ........................... Motor & 2 Roll Drive 10 ..................... TC396-7 ....................... Euro Gun Adaptor 11 ..................... CP101-0l18 .................. Gas Valve 12 ..................... W11-11/1 ...................... Hose Tail (2) 13.. ................... OCL8 ............................ ‘0’ Clip 8mm 14 ..................... AM1 77 .......................... Spool Holder Assembly
......................
Includes 14.1 ............... AM133-3 ....................... ‘R’ Clip
15.. ................... W41 -26... ...................... Power Indicator Loom Includes 15. l ............... W1 7-0/1 1 ...................... Indicator Light 15.2 .............. .CP34-3612 .................... Wirespeed Potentiometer
16 ..................... W41 -27.. ....................... Control Loom Includes 16.1 ............... CP27-11/26 .................. Cycle Arc Potentiometers (2)
17. .................... W41 -28. ........................ Power Loom 18 ..................... HF200-1/15 .................. Mounting Foot (4) 19 ..................... MC36-56/21 .................. Male Bush 20 ..................... CP5-0/8 ........................ Female Bush 21 ..................... H909 ............................. Cable Clamp 22 ..................... W41-0/1 ........................ Hinge L.H. 23 ..................... W41-0/2 ........................ Hinge R.H. 24.. ................... W29-1/20.. .................... Slam Action Latch (2) 25. .................... W5-IOl19. ..................... Potentiometer Knob. Small (2) 26 ..................... W1 1 -0/16.. ................... .Potentiometer Knob. Large 27 ..................... S140-0/1 ....................... Handle 28 ..................... WIN280 ........................ Front Label 29 ..................... WIN273 ........................ Side Label (2) 30 ..................... WIN 286 ....................... Internal Label 31 ................... ..CP102-0/18 .................. PCB Support (4) 32. .................... RUB1 6SQA .................. Insulation Guard
WELDMATIC W41-0 WIREFEEDER MANUAL Page 9
3
FIGURE 3. W41 -0 WIREFEEDER ASSEMBLY
Page I O WELDMATIC W41-0 WIREFEEDER MANUAL
8. SERVICE INFORMATION
P;
3 W ,
0 L
0 U
\
1""- II L c
1 L""
- ""
FIGURE 4. WIREFEEDER CIRCUIT DIAGRAM
WELDMATIC W41-0 WIREFEEDER MANUAL Page l 1
9. PARTS LISTS
BEXT2-4E31OAE GUN ASSEMBLY
1 .... BE4392 .............. Nozzle 2 .... BE7497 .............. Contact Tip 0.6mm ...... BE7488 .............. Contact Tip 0.8mm ...... BE7489 .............. Contact Tip 0.9mm ...... BE7490 .............. Contact Tip 1.2mm 3 .... BE4435 .............. Head 4 .... BE4423R ........... Cap 5 .... BE4780 .............. Nut Insulator 6 .... BE1370117 ........ Insulator 7 .... BE1370116 ........ Body Tube 8 .... BE1780006 ........ Handle Kit 9 .... BE5662 .............. Trigger 10 .. BE1880004 ........ Screw Kit
14 ... BE1480012 ........ Cable 3M. 15 ... BE4E213B ......... End Fitting 16 ... BE4305 .............. Cone Nut 17 ... BE2660001 ........ Terminal 18 ... BE1520008 ........ Clamp 19 ... BE252001 7 ........ Strain Relief, Flexible 20 ... BE1470007 ........ Bushing 21 ... BE1 8801 35 ........ Strain Relief, Rigid 22 ... BE2280002 ........ Screw 23 ... H2072 ................ Insulated Link 24 ... BE4816 .............. Nut 25 ... BE5060 .............. Euro Block 26 ... BE4421 .............. ' 0' Ring 27 ... BE431 10 ............ Liner 0.9 - l .2mm
To replace liner: Disconnect gun cable assembly from the Euro adaptor on the machine case, remove nozzle (l) and head (3). Withdraw old liner from the wirefeeder end. Insert new liner and refit gun cable assembly to Euro adaptor on the machine case. At the gun end, compress the liner within the gun cable, then cut it one contact tip length past the end of the body tube (7). Refit head, tip and nozzle.
FIGURE 5. BEXT2-4E31OAE (300 AMP) GUN CABLE ASSEMBLY
Page 12 WELDMATIC W41-0 WIREFEEDER MANUAL
W50-0. TWO ROLL DRIVE ASSEMBLY
ITEM # PART # DESCRIPTION
l .......... W50-0/11 ...... Feed Plate 2 .......... W51 -0/15 ..... ,Woodruffs Key 3x63 3 .......... W51-0/16 ...... Circlip (2) 4 .......... W51-0/19 ...... Parallel Key 4x4.8 5 .......... W51-O/2 ........ Feed Roll 0.9mm+l.2mm 6 .......... W51-0/20 ...... Fixing Cap 7 .......... W50-0/12 ...... Shaft 8 .......... W5 Q-0/13 ...... Pressure Arm 9 .......... W50-0/14 ...... Shaft I O ........ W51-0/37 ...... Circlip 1 l ........ W50-0/15 ...... Fixing Arm 12 ........ W50-0/16 ...... Calibrated Collar 13 ....... .W50-0/17 ...... Pressure Spring 14 ....... .W50-0/18 ...... Cap for Fixing Shaft 15 ........ W51 -O/32 ...... Circlip (2) 16 ........ W51 -0/33 ...... Inlet Guide 17 ....... .W51 -0134 ...... Wire Guide Tube 18 ........ W51 -0/35 ...... Motor & Gearbox 19 ....... .W50-0/19 ...... Bearing D30
20 ........ W50-0/20 ...... Distance Ring 21 ........ W50-0/21 ...... Distance Ring 22 ........ W50-0/22 ...... Pressure Arm Spring 23 ........ W50-0/23 ...... Screw M6x12 (3) 24 ........ W51-0/39 ...... Circlip 25 ........ W50-0124 ...... Insulating Washer (2) 26 ........ W50-0/25 ...... Insulating Washer (2) 27 ........ W50-0/26 ...... Spring Pin 28 ........ W51-0/40 ...... Screw M6x6 (3) 29 ........ W50-0/27 ...... Adaptor Ring
ALTERNATIVE PARTS
(IO) ..... W51-0/3 ........ Feed Roll 0.9mm+1.2mm “U” (IO) ..... W51-0/1 ........ Feed Roll 1.2mm+l.6mm Knurled (IO) ..... W51-0/4 ........ Feed Roll 0.8mm+l .Omm “V” (IO) ..... W51-0/5 ........ Feed Roll 0.6mm+0.8mm “V”
FIGURE 6. W50-0 TWO ROLL DRIVE ASSEMBLY
AM286-8/40 INTER-CONNECTING LEAD KIT
ITEM # ................. PART #................................DESCRIPTION
1 .......................... AM286-1/10 ......................... Work Lead
1 .l ........................ CABW35 ............................. Welding Cable 50mm* Includes
1.2 ........................ cx21 ................................... Plug 1.3 ........................ C232-CM ............................. Work Clamp 1.4 ........................ H1423 .................................. Crimp Lug
2 .......................... AM286-2/1 Q ......................... Weld Lead
2.1 ........................ CABW35 ............................. Welding Cable 56mm* Includes
2.2 ........................ cx21 ................................... Plug 2.3 ........................ HI422 .................................. Crimp Lug
3 .......................... AM282-3/10 ......................... Control Lead
3.1 ........................ CAB4C32 ............................ Cable 4 Core 3.2 ........................ AMI 12-3/1 ........................... Control Plug 3.3 ........................ H1972ET ............................. Quick Connect Lug Female (4)
Includes
3.4 ........................ H I 138 .................................. Insulator (4)
4 .......................... AM282-4/10. ....................... .Gas Hose
4.1 ........................ 6251 3 .................................. Gas Hose 5mm 4.2 ........................ OCL13 ................................. ‘0’ Clip 1/2” (2)
Includes
WELD LEAD
CONTROL. LEAD 8”3/3Q
GAS HOSE AM282-4/10
FIGURE 7. AM286-0/10 INTER-CONNECTING LEAD KIT
Paae 14 WELDMATIC W41-0 WIREFEEDER MANUAL
I O . SAFE PRACTICES WHEN USING WELDING EQUIPMENT
These notes are provided in the interests of improving operator safety. They should be considered only as a basic guide to Safe Working Habits. A full list of Standards pertaining to industry is available from the Standards Association of Australia, also various State Electricity Authorities, Departments of Labour and Industry or Mines Department and other Local Health or Safety Inspection Authorities may have additional requirements. WTlA Technical Note TN7-98 also provides a comprehensive guide to safe practices in welding.
EYE PROTECTION NEVER LOOK AT AN ARC WITHOUT PROTECTION. Wear a helmet with safety goggles or
glasses with side shields underneath, with appropriate filter lenses protected by clear cover lens. This is a MUST for welding, cutting, and chipping to protect the eyes from radiant energy and flying metal. Replace the cover lens when broken, pitted, or spattered.
Recommended shade filter fens. Amps TIG MMAW MIG Pulsed MIG 0-100 ............ 10 ................. 9 ................... 10 ................. 100-150 ......... 11 ................. IO ................. IO ................. 150-200 ......... 12 ................. 10-11 ............ 11-12 ............ 200-300 ......... 13 ................. I 1 ................. 12-13 ............ 300-408 ......... 14 ................. 12 ................. 13 .................
2-1 3 2-1 3 2-1 3 2-1 3 4
400-500 ............................ " 13 ................. 14 ................. 14 500 + .................................................. " " 14 ................. 14
BURN PROTECTION. The welding arc is intense and visibly bright. Its radiation can damage eyes, penetrate lightweight
clothing, reflect from light-coloured surfaces, and burn the skin and eyes. Burns resulting from gas- shielded arcs resemble acute sunburn, but can be more severe and painful.
Wear protective clothing - leather or heat resistant gloves, hat, and safety-toe boots. Button shirt collar and pocket flaps, and wear cuffless trousers to avoid entry of sparks and slag.
Avoid oily or greasy clothing. A spark may ignite them. Hot metal such as electrode stubs and work pieces should never be handled without gloves.
Ear plugs should be worn when welding in overhead positions or in a confined space. A hard hat should be worn when others are working overhead.
Flammable hair preparations should not be used by persons intending to weld or cut.
TOXIC FUMES. Adequate ventilation with air is essential. Severe discomfort, illness or death can result from fumes,
vapours, heat, or oxygen depletion that welding or cutting may produce. NEVER ventilate with oxygen. Lead, cadmium, zinc, mercury, and beryllium bearing and similar materials when welded or cut may
produce harmful concentrations of toxic fumes. Adequate local exhaust ventilation must be used, or each person in the area as well as the operator must wear an air-supplied respirator. For beryllium, both must be used.
Metals coated with or containing materials that emit fumes should not be heated unless coating is removed from the work surface, the area is well ventilated, or the operator wears an air-supplied respirator.
Work in a confined space only while it is being ventilated and, if necessary, while wearing air- supplied respirator.
WELDMATIC W41-0 WIREFEEDER MANUAL Page 15
Vapours from chlorinated solvents can be decomposed by the heat of the arc (or flame) to form PHOSGENE, a highly toxic gas, and lung and eye irritating products. The ultra-violet (radiant) energy of the arc can also decompose trichlorethylene and perchlorethylene vapours to form phosgene. Do not weld or cut where solvent vapours can be drawn into the welding or cutting atmosphere or where the radiant energy can penetrate to atmospheres containing even minute amounts of trichlorethylene or percholorethylene.
FIRE AND EXPLOSION PREVENTION. Be aware that flying sparks or falling slag can pass through cracks, along pipes, through windows or
doors, and through wall or floor openings, out of sight of the operator. Sparks and slag can travel up to 10 metres from the arc.
Keep equipment clean and operable, free of oil, grease, and (in electrical parts) of metallic particles that can cause short circuits.
If combustibles are present in the work area, do NOT weld or cut. Move the work if practicable, to an area free of combustibles. Avoid paint spray rooms, dip tanks, storage areas, ventilators. If the work can not be moved, move combustibles at least 10 metres away out of reach of sparks and heat; or protect against ignition with suitable and snug-fitting fire-resistant covers or shields.
Walls touching combustibles on opposite sides should not be welded on or cut. Walls, ceilings, and floor near work should be protected by heat-resistant covers or shields.
A person acting as Fire Watcher must be standing by with suitable fire extinguishing equipment during and for some time after welding or cutting if;
Combustibles (including building construction) are within 10 metres.
Combustibles are further than 10 metres but can be ignited by sparks.
Openings (concealed or visible) in floors or walls within 10 metres may expose combustibles to sparks.
Combustibles adjacent to walls, ceilings, roofs, or metal partitions can be ignited by radiant or conducted heat.
After work is done, check that area is free of sparks, glowing embers, and flames. A tank or drum which has contained combustibles can produce flammable vapours when heated.
Such a container must never be welded on or cut, unless it has first been cleaned as described in AS.1674-1974, the S.A.A. Cutting and Welding Safety Code. This includes a thorough steam or caustic cleaning (or a solvent or water washing, depending on the combustible's solubility), followed by purging and inerting with nitrogen or carbon dioxide, and using protective equipment as recommended in AS.1674-1974. Water-filling just below working level may substitute for inerting.
Hollow castings or containers must be vented before welding or cutting. They can explode. Never weld or cut where the air may contain flammable dust, gas, or liquid vapours. SHOCK PREVENTION.
Exposed conductors or other bare metal in the welding circuit, or ungrounded electrically alive equipment can fatally shock a person whose body becomes a conductor. Ensure that the machine is correctly connected and earthed. If unsure have machine installed by a qualified electrician. On mobile or portable equipment, regularly inspect condition of trailing power leads and connecting plugs. Repair or replace damaged leads.
Fully insulated electrode holders should be used. Do not use holders with protruding screws. Fully insulated lock-type connectors should be used to join welding cable lengths.
Terminals and other exposed parts of electrical units should have insulated knobs or covers secured before operation.