Overview#
The Cummins C1000 N6 is a 1000 kW standby natural gas generator set built on the QSK60G engine -- a 60-liter V16 turbocharged and charge air aftercooled platform. EPA NSPS and Non-Road Mobile factory certified, the C1000 N6 is designed for large commercial and industrial standby applications where natural gas fuel is preferred over diesel for emissions, fuel storage, or operational reasons.
With 36.4% electrical efficiency and 52.4% thermal efficiency, the C1000 N6 can deliver significant combined heat and power (CHP) value in applications that can utilize the thermal output.
Engine specifications#
The QSK60G is a purpose-built gas engine:
- V-16 configuration: 159 mm bore x 190 mm stroke, 11.4:1 compression ratio
- Turbocharged and charge air aftercooled for maximum power density
- 1800 rpm rated speed with 11.4 m/s piston speed
- 2P2L cooling: Two-pump, two-loop architecture separating high-temperature (jacket water, 90C outlet) and low-temperature (charge air, 54C outlet) circuits
- 379 liters lube oil capacity with full load lubricating oil consumption of 0.15 g/kWe-hr
- 1082 kWm gross engine power output (1451 hp)
Fuel consumption and efficiency#
Operating on pipeline natural gas (LHV 35.64 MJ/Nm3, minimum Methane Index 55):
| Load | Fuel Input (MMBTU/hr) | Electrical Efficiency | Thermal Efficiency |
|---|---|---|---|
| 100% | 9.85 | 36.4% | 52.4% |
| 90% | 8.98 | 35.9% | 52.6% |
| 75% | 7.68 | 35.0% | 53.0% |
Gas supply pressure at the fuel shutoff valve (FSOV) inlet must be maintained at 0.2 - 0.46 bar (2.9 - 6.7 psi).
Cooling system#
The 2P2L cooling architecture provides separate management of engine jacket water and charge air cooling:
- HT (high-temperature) circuit: 182 L engine coolant volume, 83 m3/hr flow rate, 90C outlet temperature
- LT (low-temperature) circuit: 34 L engine coolant volume, 23 m3/hr flow rate, 54C outlet temperature
- Maximum HT circuit pressure: 4.5 bar (65 psig)
- Remote radiator cooling option available for installations requiring separated cooling
Heat rejection data#
At full rated load:
- HT circuit: 719 kW (2.45 MMBTU/hr)
- LT circuit: 85 kW (0.29 MMBTU/hr)
- Exhaust (to 120C): 795 kW (2.71 MMBTU/hr)
- Radiated to ambient: 126 kW (0.43 MMBTU/hr)
- Exhaust temperature after turbine: 500C (932F)
Alternator options#
The C1000 N6 supports a wide voltage range from 380V through 13,800V:
- Low voltage (380-480V): Temperature rise options of 80C, 105C, and 125C
- Medium voltage (4160V): For campus distribution systems
- High voltage (12,470-13,800V): Direct utility interconnection
- All configurations standby duty rated
Derating considerations#
The C1000 N6 provides detailed altitude and temperature derating tables. At standard conditions (30 in Hg barometric, 25C air filter inlet), full rated power is available. Key derating thresholds:
- Above 40C inlet temperature at sea level: derating begins
- Above 1000 m (3281 ft) at 40C: approximately 3% derate per 1000 ft
- Methane Index below 55: consult factory for adjusted ratings
Our service experience#
The QSK60G is a well-engineered gas platform. With 16 cylinders, spark plug management is the primary routine maintenance item. The 2P2L cooling system requires monitoring of both HT and LT circuits independently -- maintaining the LT inlet below 50C is critical for charge air temperature control. Gas supply pressure stability is essential: pressure drops below 2.9 psi at the FSOV during load transients will cause load acceptance failures. We recommend gas regulator sizing with at least 2x capacity margin for the peak flow demand. The 379-liter oil capacity provides stable oil temperatures but represents a significant oil change cost -- oil analysis programs are recommended to extend drain intervals where supported by results.
