Cummins · Cummins D6 Commercial Diesel

Cummins C275 D6

275 kW standby / 250 kW prime · Diesel · Liquid-cooled

275 kW EPA Tier 3 diesel standby generator with Cummins QSL9-G7 inline-6 engine and PowerCommand 2.3 control. HPCR fuel system, sound-attenuated enclosure, for commercial and industrial standby applications.

Cummins Cummins C275 D6 generator — specifications and details
Standby power
275 kW / 250 kW prime
Voltage options
120/208V, 277/480V, 347/600V
Frequency / Phase
60 Hz · 3-phase
Engine
Cummins QSL9-G7 · 8.8L
EPA / Emissions
Tier 3
Commerciallight-industrialData Centers
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Overview#

The Cummins C275 D6 (model designation DQDAB) is a 275 kW standby diesel generator set built on the QSL9-G7 engine -- an 8.8-liter, inline-6-cylinder turbocharged and charge-air-cooled industrial diesel running at 1800 rpm. Rated at 344 kVA standby and 313 kVA prime at 60 Hz, the DQDAB is the mid-range model in the QSL9 generator family between the 250 kW DQDAA and 300 kW DQDAC.

Cummins also offers a Tier 4 Final variant, the C275D6D, which uses the QSL9-G9 engine with PCC 3300 control and an S4L1S-F4 alternator. The C275D6D carries a higher DCC rating of 545 kW (681 kVA) and does not include a sound enclosure as standard.

Standard equipment on the DQDAB includes the PowerCommand 2.3 control with AmpSentry protective relay, an HCI434F alternator, and a sound-attenuated enclosure. The engine features Bosch high-pressure common rail (HPCR) fuel injection, a Holset HX40 wastegated turbocharger, and integrated fluid circuits. EPA Tier 3 certified.

The DQDAB is designed for large commercial standby applications including hospitals, data centers, and industrial facilities.

Our Service Experience#

The QSL9-G7 at 275 kW is operating near the upper end of its standby rating range. We pay close attention to fuel injection system health and turbocharger condition on these units. The HPCR fuel system is the most critical maintenance item -- fuel contamination or water intrusion will damage injectors quickly. We recommend annual injector performance testing and fuel system pressure checks on units that see limited run hours. The Holset HX40 turbocharger should be inspected for shaft play at every major service interval.

Frequently Asked Questions#

What fuel consumption should I expect from the DQDAB? Standby fuel consumption at full 275 kW load is approximately 21.5 gallons per hour. At 50% load, consumption drops to approximately 11.8 gallons per hour. These figures are derived from the QSL9-G7 engine spec sheet and scaled for the 275 kW genset output.

Can the C275 D6 be paralleled? Yes. The PowerCommand 2.3 control supports paralleling. The C275D6D with PCC 3300 control offers enhanced paralleling features including digital synchronization.

Engineering specifications

Physical

Length
150 in
Width
56 in
Height
72 in
Dry weight
5,700 lb

Fuel system & runtime

Fuel use @ full load
21.5 GPH
Fuel use @ 50% load
11.8 GPH

Documents & downloads

Spec sheets & manuals

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Estimate runtime for the Cummins C275 D6

Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.

Estimate runtime on this tank

Estimated runtime

12.1 hours(0.5 days)

Fuel consumption ≈ 16.59 GPH at 75% load. Estimate based on industry-typical 1800 RPM standby curves (≈0.07 GPH/kW at full load). Actual consumption varies by engine, ambient temperature, fuel quality, and tuning.

Service intervals

Manufacturer-recommended intervals for the Cummins C275 D6 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 500 hours or 12 months
Air filter
Every 500 hours
Fuel filter
Every 500 hours
Major overhaul
≈ 25,000 hours

Common failure modes

What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.

ComponentSymptomTypical hoursSeverity
HPCR fuel injection systemInjector fault codes, rough running, power loss, fuel in oil—severe
Fleetguard fuel filter assemblyFilter clogging, restricted fuel flow, hard start under load—moderate
Charge air coolerCoolant in intake, white smoke, power loss on high-load events—severe
Holset HX40 turbocharger bearingIncreased turbo noise, oil consumption, reduced boost pressure—moderate

Frequently Asked Questions

What engine does the Cummins C275 D6 use?
Cummins offers two 275 kW diesel generator configurations. The DQDAB uses the QSL9-G7 engine (8.8L, inline-6, Tier 3) with PowerCommand 2.3 control. The C275D6D uses the QSL9-G9 engine (also 8.8L, inline-6) with PCC 3300 control and EPA Tier 4 Final certification. Both run at 1800 rpm with turbocharged and charge-air-cooled aspiration.
What are the standby and prime ratings of the C275 D6?
Standby rating is 275 kW (344 kVA) at 60 Hz, 0.8 power factor. Prime rating is 250 kW (313 kVA). The DQDAB also carries a DCC rating of 455 kW (569 kVA). Both at 1800 rpm.
What is the difference between the DQDAB and C275D6D?
The DQDAB uses the QSL9-G7 engine with PowerCommand 2.3 control and EPA Tier 3 certification. The C275D6D uses the QSL9-G9 engine with PCC 3300 control and EPA Tier 4 Final certification. The C275D6D does not include a sound enclosure as standard. The Tier 4 model is required for installations subject to newer emissions regulations.
What are the service intervals for the C275 D6?
Oil and filter changes are due at 500 hours or 12 months, whichever comes first. Air filter and fuel filter replacement at 500-hour intervals. Coolant flush at 4,000 hours. Major overhaul interval is 25,000 hours under standard standby duty conditions.
Can OnPoint Generators service the C275 D6 in Northern California?
Yes. OnPoint Generators serves the San Francisco Bay Area, Silicon Valley, and broader Northern California with authorized Cummins service. We carry QSL9 parts, InPower diagnostic tooling, and provide annual maintenance, load bank testing, and emergency response for 275 kW installations.

Compatible equipment

Transfer switches

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