SR4 SERIES B GENERATORS

THEPOWER OFQUALITY

Trust Caterpillar to take one of the most successful lines of

generators the world over, the SR4, and better it.

In over 250,000 applications around the world, Cat® SR4

generators have proven their worth.With the introduction of

the SR4B full line of brushless generators, the next generation

of power takes on added dimensions in quality, versatility,

serviceability and reliability.

Whether the call is for prime, standby or continuous

power, no matter the application, from powering buildings,

landfills and oil rigs, to ships at sea, there is an SR4B

The Power Of

configuration to meet your electric power generation

requirements.

In fact, the SR4Bs offer the widest range of products in the

industry. From 100 kW to 2,000 kW, and all the standard

voltages from 120 to 5,000 volts at 50 and 60 Hz, you’ll find an

SR4B that is perfectly performance-matched to a Cat diesel or

gaseous-fueled engine to power your most particular needs.

Versatility.

The New Family of 3500 Series B Gen Sets.

Constructed for durability, designed for serviceability, and

engineered for power quality, the SR4B has undergone a

myriad of changes and innovations to make it the best ever Cat

line for the broadest ever applications calling for large and

medium frame generators.

For durability, all SR4Bs are entirely built to meet Class H

insulation requirements. State-of-the-art polyester resins are applied

using Vacuum Pressure Impregnation (VPI) on large frame, and dip

and bake on medium frame SR4Bs.The addition of epoxy overcoat,

heavy-duty output leads, and voltage regulator sensing lines, assure

superior insulation isolation at higher operation temperatures. In

addition to being equipped with the best rotor in the business,

these generators are constructed with a more robust stator, and a

reconfigured air flow path for cleaner, cooler running.

As for serviceability, the SR4B is hard to beat. Designed so that

most serviceable parts are accessible within 60 minutes, these

generators have been given shorter frame sizes, replaceable

bearing sleeves on large frame generators, and a large terminal

box designed to provide easy access to internal components.The

terminal box is positioned to allow cables to be brought in from

four directions for simpler, easier hookups. In addition, easily

accessible connections are now standard for convenient control

connections and troubleshooting.

The flexibility of the SR4B is enhanced by its larger number of

size steps.By also offering shorter frame sizes,2-bearing versions,

either Permanent Magnet or Self-Excited excitation systems,

oversizing capability, a variety of attachments, and performance-

matching to Cat gas or diesel engines, the SR4B’s range of

applications extends beyond anything else in the industry.

STATORForm wound windings available with Vacuum PressureImpregnated Class H insulation for superior handlingof high switching loads and harmonics.

ROTORPrecision “wet” layer wound ensuresbonding of coils to laminations andsealed insulation system. Individuallytested at 125% of rated speed at 170° C fortwo hours.

LARGE BEARING SLEEVEEasy access, replaceable bearing

sleeves for quicker, simpler maintenance.

BuiltForPowerFr

CIRCUIT BREAKERAll 3 or 4 pole breakersstandard with shunt trip.

TERMINAL BOXTop mounted modular design for easierhookups. Oversizedfor greateraccessibility andgreater add-oncapability.

SERVICE ACCESSStator and terminal boxdesigned to afford access tomost serviceable parts within60 minutes.

omTheGroundUp.

Raw PowerBecomes

Quality Power.When it comes to quality power, control is everything. From the solid state

VR3 and VR3F, to the advanced microprocessor-based digital voltage

regulator, all Cat regulators are designed to optimize the power quality of

every SR4B configuration.

As an added convenience,the regulator is electrically isolated from the

generator output on large frame generators through sensing transformers,

thereby filtering incoming harmonics to the regulator. And because

minimizing harmonic distortion is critical to maximizing power quality,every

SR4B also offers optimum winding pitch.

Caterpillar. Powering The Way.Cat SR4Bs deliver improved efficiency over the previous SR4

generators. Considering the success of the SR4, that’s quite an

achievement. It’s by constantly utilizing

the latest in advanced technologies,

innovation and design that Cat engineers

and technicians keep all Cat products at

the forefront of their industry.

To assure that the SR4B you get is all that you expected, all

are subjected to extensive factory testing where they are

checked both separately and as part of a complete

generator set for a variety of functions including:

waveform, line-to-line voltage, no-load circulating

current, full load and transient load capabilities,

and speed and voltage stability.

Compare Cat SR4Bs To Other Generators.

World-class design—Performance andstructurally matched to engine.

Designed to the generator output onlybecause it is used on engines by variousmanufacturers.

Optimized design for both engine andgenerator through system modeling.

Stator coil pitch,coil distribution,and skeware designed to produce optimum waveformand minimum total harmonic distortion.

Most competitors offer 2/3 stator coilpitch only, with higher line-to-linedistortion.

Ensures optimum voltage waveform andless heating effects through lowerharmonics.

Isolation transformers are now standardon all large frame SR4B permanentmagnet generators.

Not always available. Convenient paralleling and systemisolation.

0.025mm peak-to-peak rotor balance (fourtimes closer tolerance than NEMA MG 1requirement).

In accordance with NEMA MG 1requirement.

Less system vibration, greater reliability,and a longer life.

Low voltage stator windings “high pot”tested at 3000 volts.

Stator windings “high pot” tested at only2000 volts.

Ensures insulation integrity for longer life.

Surge rope and tape are added to the endturns to hold the end turns stationaryduring surges, motor starting andtransients.

Some competitors use no tape on endturns of stator coils.

The tape protects the coil end turns fromabrasion between coils and protectsagainst coil-to-coil or phase-to-phase shortcircuits.

3-Phase Sensing Not always standard on any regulator;offered as an add-on at a higher price.

Superior voltage regulation withunbalanced loads; improves responseto distorted waveforms of SCR typeloads.

Digital Voltage Regulator Not available. Superior transient response, blockloading, generator protection,flexibility, and immunity to harmonicdistortion.

Provisions made for circuit breakermounting in terminal box and topmounted control panels. Separatecompartment for control devices.

Terminal box not designed for circuitbreaker mounting or top mounted controlpanels.

Convenient generator mounted circuitbreakers and control panels require noextra floor space.

Three separate neutrals in large frameSR4B terminal boxes (available onmedium frame).

Some competitors offer one neutral only. Separate neutrals allow installation ofdifferential protection circuitry.

Readily accessible terminal blocks (DINrail mounted on large frame SR4Bs)designed and located for customerconvenience.

Not always available. Allows easy customer connections toregulators, space heater and otherdevices.

Four direction (top, bottom, left and rightside) terminal accessibility.

Limited terminal accessibility. Greater convenience for customer loadconnection.

Caterpillar offers a complete system —engine, generator and controls, providingblock load transient and motor startinganalysis based on the engine-generatorcombination.

Competition does not offer this featurebecause of its use by various enginemanufacturers.

Caterpillar provides estimatedperformance of package generator sets bycalculating voltage and frequencyexcursions.

Rotors are designed and prototype testedat 150% overspeed for two hours at 170° C ambient.

Designed for 125% overspeed. Ensures mechanical design integrity forincreased reliability and longer life.

Complete engine-generator systemtesting including mounting evaluation,wiring and control compatibility, linearvibration analysis and transientperformance.

Not usually offered as a factory-assembled,tested package.

Single source responsibility ensurescombination of equipment will performreliably each time, every time.

Temperature rise tested by bothresistance and embedded thermocouple.

Thermal limits set by resistance methods— most measure rise and mathematicallycalculate average temperature rise acrossrotor and stator.

Ensures against localized insulation “hotspots.”

Features Cat SR4B Competition SR4B Benefit

Generator Design

Manufacturing

Prototype Testing

Stator Construction

Voltage Regulation

Terminal Box

Product Support

CATERPILLAR.YOUR LOCAL RESOURCE.

WORLDWIDE.Making sure that customers get all the quality and all the value out

of their products that Caterpillar has put into them is the job ofthe 1,200 strong worldwide Cat dealer facilities network. Fromapplication matching, to maintenance, to financing, all the way tocommissioning, your local Cat dealer has all the manpower andexpertise you need to keep your generator producing nothing butquality power.

Your cat dealer is prepared to answer any questions you may haveabout SR4B Generators, Gas or Diesel Engines, as well as CustomerSupport, Parts or Service. For the name and number of the Cat dealernearest you, just call Caterpillar Inc.World Headquarters in Peoria,Illinois, U.S.A., or the subsidiary office in your corner of the world.

North AmericaCaterpillar Inc.

Peoria, Illinois, U.S.A.Phone: (309) 675-1000

Europe, Africa, Middle EastCaterpillar Overseas S.A.

Geneva, SwitzerlandPhone: (41) - (22) 849-4444

AsiaCaterpillar Asia Pte., Ltd.

SingaporePhone: (65) 662-8399

ChinaCaterpillar China Ltd.

Hong KongPhone: (852) 2848-0333

JapanCaterpillar Power Systems Inc.

Tokyo(81) 3-3593-3232

AustraliaCaterpillar of Australia Ltd.

Victoria, AustraliaPhone: (03) 9339-9333

Mexico, The Caribbean, South AmericaCaterpillar Americas Co.

Peoria, Illinois, U.S.A.Phone: (309) 675-4774

©1996 Caterpillar Printed in U.S.A. LEDX5004