Overview#
The Cummins C150 N6 is a 150-kilowatt natural gas and propane standby generator built on the QSJ8.9G 8.9-liter turbocharged inline-6 engine — stepping up from the naturally aspirated C60 N6 with the additional power density that turbocharged gaseous engines provide. The C150 N6 occupies the mid-range of the C-Series commercial gaseous lineup and is commonly specified for hotels, large multi-family buildings, hospital non-critical branches, and campus standby applications.
At 150 kW standby (188 kVA), the C150 N6 is listed to UL 2200 and certified to EPA SI Stationary Emission standards (40 CFR 60 Subpart JJJJ). The unit is NFPA 110 Level 1/2 capable when properly accessorized, and the engine operates within a standard gas supply pressure range of 6-13 in. H₂O at the engine connection.
The generator set wet weight is 1,776 kg (3,915 lbs) in standard configuration.
Technical Specifications#
| Parameter | Value |
|---|---|
| Standby Rating | 150 kW (188 kVA) |
| Frequency | 60 Hz |
| Power Factor | 0.8 |
| Engine Model | QSJ8.9G |
| Displacement | 8.9 liters |
| Configuration | Cast iron, inline-6 |
| Aspiration | Turbocharged and aftercooled |
| Gross Engine Power | 179 kWm (240 bhp) |
| Bore x Stroke | 114.1 mm x 144.5 mm |
| Compression Ratio | 9.7:1 |
| Rated Speed | 1800 rpm |
| Cooling | Set-mounted radiator, 45 °C ambient design |
| Coolant Capacity (with radiator) | 26 L (6.9 US gal) |
| Unit Wet Weight | 1,776 kg (3,915 lbs) |
Natural gas fuel consumption (SCFH):
| Load | SCFH |
|---|---|
| 25% | 719 |
| 50% | 1,111 |
| 75% | 1,487 |
| 100% | 1,915 |
Fuel inlet pressure: 1.5 to 3.5 kPa (6 to 13 in. H₂O) at engine connection.
Available voltage configurations:
- 1-phase: 120/240V
- 3-phase: 120/208V, 120/240V, 277/480V, 347/600V, 127/220V
Our Service Experience#
The C150 N6 serves institutional accounts where diesel storage is impractical or prohibited. The QSJ8.9G's turbocharged design adds power density but introduces turbocharger health as a primary maintenance focus. Our service program for these units includes:
- Spark plug inspection and replacement at 1,500-hour intervals
- Turbocharger inspection for bearing wear and oil consumption at every major service
- Air/fuel ratio validation under load — turbocharged gaseous engines are sensitive to gas supply pressure variations
- Charge air cooler inspection for fouling or leakage
- Annual battery load test with replacement every 3-4 years
Natural gas supply pressure validation is critical at commissioning and should be re-verified any time utility distribution changes occur upstream of the installation. Fuel supply pressure outside the 6-13 in. H₂O range under load will cause performance degradation and potential fault codes.
Frequently Asked Questions#
What engine does the C150 N6 use? The Cummins QSJ8.9G — a turbocharged and aftercooled 8.9-liter cast iron inline-6 spark-ignited engine. Bore is 114.1 mm (4.49 in.), stroke is 144.5 mm (5.69 in.), compression ratio 9.7:1, rated at 1800 rpm. Gross engine output is 179 kWm (240 bhp) at standby.
What is the fuel consumption of the C150 N6 at full load on natural gas? At 100% standby load: 1,915 SCFH. At 75%: 1,487 SCFH. At 50%: 1,111 SCFH. At 25%: 719 SCFH. These figures are from the NAS-6303-EN spec sheet at standard conditions.
What fuel supply pressure does the C150 N6 require? Minimum 1.5 kPa (6 in. H₂O) and maximum 3.5 kPa (13 in. H₂O) at the engine fuel train connection under operating load.
Is the C150 N6 suitable for hospital standby? The C150 N6 is appropriate for hospital non-critical branches and supplemental standby loads. For NFPA 99 life-safety and critical branch coverage, confirm that the specific installation meets the transfer time and runtime requirements with your AHJ. Natural gas supply interruptions during disasters are a key risk consideration for healthcare facilities — many codes require diesel for primary life-safety coverage.
What voltages does the C150 N6 support? Single-phase and three-phase configurations: 120/240V, 120/208V, 277/480V, 347/600V, and 127/220V. Three-phase is the primary configuration at 150 kW.
