D125 GC C7.1 (60 HZ) | 125 kW Diesel Generator

Diesel Generator Sets D125 GC

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Key Specs

Maximum Rating
125 ekW
125 ekW
Minimum Rating
125 ekW
125 ekW
Emissions/Fuel Strategy
U.S. EPA Cert., Tier 3
U.S. EPA Cert., Tier 3


125 ekW Diesel Generator Set

Producing reliable power of 125 ekW at 60 Hz, our D125 GC diesel generator sets designed to ISO 8528-5 transient response requirements. All D125 GC generator sets are available with a choice of emissions levels.


Reliability tested for 500 Hours

Ensures you can count on emergency power when it is needed

Saves up to 11% Installed Space

Requires less space for installation; leaves more room for your on-going operations

Spare Parts 98% Fulfillment within 24 hours

World's best product support network ensures spare parts are readily available for maintenance and service needs

Product Specifications for D125 GC

Maximum Rating 125 ekW 125 ekW
Minimum Rating 125 ekW 125 ekW
Emissions/Fuel Strategy U.S. EPA Cert., Tier 3 U.S. EPA Cert., Tier 3
Voltage 208 to 600 Volts 208 to 600 Volts
Frequency 60 Hz 60 Hz
Speed 1800 rpm 1800 rpm
Duty Cycle Standby Standby
Engine Model C7.1 I-6, 4-Cycle Diesel C7.1 I-6, 4-Cycle Diesel
Bore 4.1 in 105 mm
Stroke 5.3 in 135 mm
Displacement 428 in³ 7.01 l
Compression Ratio 16.7:1 16.7:1
Aspiration Turbocharged, Air to Air Aftercooled Turbocharged, Air to Air Aftercooled
Fuel System Electronic, Common Rail Electronic, Common Rail
Governor Type ADEM™A4 ADEM™A4
Length - Maximum 103.7 in 2634 mm
Width - Maximum 51.2 in 1300 mm
Height - Maximum 52.2 in 1402 mm
Dry Weight - Genset (maximum) 3099 lb 1406 kg

D125 GC Standard Equipment

Air Inlet System

  • Air cleaner; light duty with disposable element

Control Panels

  • GCCP 1.2 Control panel

Cooling System

  • Fan drive, battery charging alternator drive
  • Coolant drain line with valves
  • Caterpillar extended life coolant
  • Radiator and cooling fan with guards

Generator and Generator Attachments

  • Segregated low voltage (AC/DC) wiring panel
  • IP23 Protection
  • Circuit breaker, IEC, 3 pole, mounted in tower panel
  • Voltage regulator (single phase sensing)
  • Tower panel, IP22, bottom cable entry
  • 12 Leads

Exhaust System

  • Stub pipe, gaskets, raincap and SAE exhaust flange for customer use - shipped loose

Fuel System

  • Base, formed steel with single wall integral 24-hour fuel tank
  • Standard open set fuel tank/base supplied

Lube System

  • Oil drain line with valve
  • Lubricating oil

Mounting System

  • Termination points for coolant and lube oil drain lines
  • Includes lifting provision and drag points
  • Captive linear vibration isolators between base and engine-generator

Starting / Charging System

  • 24V battery with rack and cables

Governing System

  • Mechanical and electrical governing system - model dependent


  • Engine and alternator pre-paint, Caterpillar yellow

D125 GC Optional Equipment

Alternator System

  • Alternator removal
  • Optional LC Frame alternator
  • R Frame auxiliary winding: R2273L4 SE aux alt 07, aux alt 08 and aux alt 10
  • Permanent magnet excitation (PMG)
  • Anti-condensation heater
  • 3 Phase sensing
  • Quatrature droop king

Circuit breakers

  • Padlockable breaker device
  • 4 Pole 250A, 400A and 630A Circuit breakers

Control Panel Options

  • Battery charger
  • Control panel heater
  • Earth fault (2 wire only)
  • Volt free contacts
  • Emergency stop with key
  • Speed adjust potentiometer
  • Earth leakage (2 wire only)
  • Overload shutdown via breaker
  • Speed adjust contacts
  • Panel mounted audible alarm

Control System

  • Volt free contacts for generator set running
  • Volt free contacts for common alarm
  • Static battery charger
  • GCCP 1.2

Cooling System

  • Coolant heater
  • Low coolant temperature
  • Low coolant level shutdown


  • Sound attenuated level 2 enclosure

Mounting Options

  • Silencer installation kit
  • Residential silencer
  • Battery removal
  • Industrial silencer removal
  • Electronic governor

Fuel Systems

  • Low fuel level shutdown
  • Open set narrow tankbase
  • Skidbase for CALG enclosure sets
  • DEFRA bunded fuel tank
  • Low fuel level alarm
  • Compact skidbase for open sets
  • High fuel level alarm

Test Reports

  • PGS Test report @ 0.8 power factor
  • PGS Test report @ 1.0 power factor


  • Stone guards/radiator trans flange

Global Certifications

  • Certification for CIS

Power Termination

  • Circuit breaker, IEC, 4 pole

Accessories / Miscellaneous

  • Packing case - compact set
  • Packing case - canopied set

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Service Agreement (Cat® CVA & LTSA)

Experience hassle-free ownership and predictable expenses with flexible Customer Value Agreements, which include Long-Term Service Agreements.

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Cat RAM and Condition Monitoring

Observe and manage your fleet from anywhere with Cat RAM, and benefit from real-time monitoring by expert advisors with Condition Monitoring.

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Shop for genuine and Cat Reman parts online, with access to price, inventory, and 24/7 expert support.

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Maintenance and Repairs

Retain genset value with maintenance, upgrade kits, and repair options that extend lifecycles, optimise performance, and help you control costs.

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