Overview#
The Cummins C1250 N6 is a 1250 kW (1563 kVA) standby natural gas generator set powered by the QSV91G -- a 91-liter, turbocharged and aftercooled spark-ignited gas engine. The QSV91G is one of the largest gas engines in the Cummins portfolio, designed specifically for high-capacity standby and continuous-duty gas applications. The unit runs on natural gas or propane vapor and is equipped with PowerCommand controls.
At 1250 kW, the C1250 N6 serves hospitals, Tier III+ data centers, large campus environments, and industrial facilities where megawatt-class gas-fired backup is required. The QSV91G platform provides the displacement and robustness needed for reliable operation at this power level without diesel fuel logistics.
Technical Specifications#
| Parameter | Value |
|---|---|
| Standby Rating | 1250 kW (1563 kVA) |
| Frequency | 60 Hz |
| Power Factor | 0.8 |
| Engine Model | QSV91G |
| Fuel Type | Natural gas / LPG |
| Cooling | Liquid |
| Aspiration | Turbocharged and aftercooled |
| Rated Speed | 1800 rpm |
| NG Fuel Consumption (Full Load) | ~12,500 CFH |
Our Service Experience#
The QSV91G is a large-frame, high-cylinder-count gas engine that requires experienced technicians, specialized tooling, and adequate service access clearance around the unit. Spark plug replacement is a significant planned maintenance event. The turbocharger system requires annual inspection for shaft play and boost pressure verification. The catalytic converter (where fitted) must be monitored for backpressure buildup.
Gas supply infrastructure at 1250 kW is a major project consideration. At approximately 12,500 CFH, the facility needs utility-grade gas service with dedicated industrial metering and appropriately sized supply piping. Lead times for gas utility service upgrades can be significant -- engage the utility during early project planning.
Frequently Asked Questions#
What engine does the C1250 N6 use? The Cummins QSV91G -- a 91-liter, turbocharged and aftercooled spark-ignited gas engine rated for 1250 kW standby at 1800 rpm.
What is the standby rating of the C1250 N6? 1250 kW (1563 kVA) at 60 Hz, 0.8 power factor. Emergency Standby Power (ESP) rating.
What are the service intervals? Oil and filter at 500 hours or 12 months. Air filter at 500 hours. Spark plugs at 1,000 hours. Major overhaul at 30,000 hours.
Can OnPoint Generators service the C1250 N6 in Northern California? Yes. OnPoint Generators maintains factory-trained staff for QSV91G gas engine service across the San Francisco Bay Area, Silicon Valley, and Northern California.
