Overview#
The Cummins C750 N6 is a 750 kW standby natural gas generator set built on the GTA50 engine platform -- a 50.3-liter, 16-cylinder heavy-duty industrial spark-ignited engine. The C750 N6 is a fully integrated power generation system with PowerCommand 3.3 controls, AmpSentry protective relay, and UL 2200 certification, designed for commercial and industrial standby power applications.
The unit accepts full rated load in a single step per NFPA 110 Type 10, making it suitable for Level 1 and Level 2 emergency power supply systems in hospitals, data centers, and other mission-critical facilities.
Engine platform#
The GTA50 is a proven industrial gas engine:
- 50.3 liters displacement from a cast iron block with replaceable wet cylinder liners
- Rugged 4-cycle spark-ignited design for reliable power on natural gas
- 2100 rpm overspeed limit with 32 kW regenerative power capability
- 1800 CCA cranking current at 0C ambient, supported by four 8D batteries on 24V starting system
- 43 amp battery charging alternator for reliable battery maintenance
PowerCommand 3.3 control system#
The integrated PowerCommand 3.3 provides comprehensive genset management:
- Digital voltage regulation: Three-phase sensing, full wave rectified, PWM output for stable operation with all load types
- Isochronous governing: Temperature-dynamic governing with configurable torque matching
- AmpSentry protection: Full range of alternator protection matched to the specific alternator -- overcurrent, short circuit, single/three-phase fault regulation, reverse power, field overload
- Paralleling capability: Phase lock loop synchronizer, sync check relay, isochronous kW/kVar load sharing, load govern control for utility paralleling
- Communications: PCCNet and Modbus standard interfaces
- 320x240 pixel graphic LCD with LED backlight for detailed operational data
Fuel consumption#
Natural gas consumption at rated loads (in standard cubic feet per hour):
| Load | C750 N6 |
|---|---|
| 25% | 4,099 CFH |
| 50% | 6,559 CFH |
| 75% | 8,608 CFH |
| 100% | 10,931 CFH |
Fuel inlet pressure at the genset connection: 381 to 508 mm WC (15 to 20 in. WC).
Alternator specifications#
The C750 N6 alternator features:
- PMG excitation: Permanent Magnet Generator for voltage build-up independent of residual magnetism
- Class H insulation per NEMA MG1-1.65
- 2/3 pitch stator winding: Low waveform distortion with non-linear loads, fault-clearing short-circuit capability
- Standard 125C temperature rise
- Full-load amp ratings across nine voltage configurations from 120/240V (single phase) through 347/600V
Our service experience#
The GTA50 engine platform requires attention to wet cylinder liner maintenance -- coolant treatment with supplemental coolant additives (SCA) is essential to prevent cavitation erosion. With 16 spark plugs to manage, a systematic replacement schedule is critical. The PowerCommand 3.3 control system is one of Cummins' most capable platforms, with the InPower service tool providing detailed diagnostics and data logging. The four spin-on oil filter canisters (combination full flow with bypass) simplify routine oil service. Natural gas supply pressure must be maintained within the 15-20 in. WC specification for proper fuel-air mixing and load acceptance.
