What are the standby and prime ratings of the C750 D6?

Standby rating is 750 kW (938 kVA) at 60 Hz, 0.8 power factor. Prime rating is 680 kW (850 kVA). Both at 1800 rpm, 60 Hz, three-phase.

What are the service intervals for the C750 D6?

Oil and filter changes are due at 500 hours or 12 months. Air filter replacement at 1,000-hour intervals. Fuel filter at 500 hours. Coolant flush at 6,000 hours. Major overhaul interval is 40,000 hours under standard standby duty conditions.

How does the C750 D6 compare to the C800 D6?

Both use the QSK23-G3 engine (23.1L, inline-6, HPI-PT). The C750 D6 is rated at 750 kW standby vs 800 kW for the C800 D6. The C750 D6 runs at a more conservative output, which may provide slightly better fuel economy and longer component life in high-utilization applications.

Can {company} service the C750 D6 in Northern California?

Yes. OnPoint Generators provides authorized Cummins service for large commercial diesel generators across the San Francisco Bay Area and Northern California. QSK23 service requires Cummins INSITE diagnostic software for HPI-PT fuel system calibration and ECM programming.

Cummins · Cummins D6 Commercial Diesel

Cummins C750 D6

Name: Cummins C750 D6
Brand: Cummins
SKU: c750-d6

750 kW standby / 680 kW prime · Diesel · Liquid-cooled

750 kW diesel standby generator with QSK23-G3 23.1L inline-6 engine and HPI-PT fuel injection. PowerCommand control, liquid-cooled, for data center, hospital, and mission-critical standby applications.

Standby power: 750 kW / 680 kW prime
Voltage options: 277/480V, 346/600V, 4160V
Frequency / Phase: 60 Hz · 3-phase
Engine: Cummins QSK23-G3 · 23.1L
EPA / Emissions: Tier 2

Commercial Manufacturing Data Centers Healthcareparalleling-array

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Overview#

The Cummins C750 D6 is a 750 kW standby diesel generator set powered by the QSK23-G3 -- a 23.1-liter, inline-6-cylinder diesel engine with Cummins' HPI-PT (Hydraulic Pressure Intensifier - Pre-combustion Technology) fuel injection. Rated at 938 kVA standby and 850 kVA prime at 60 Hz, the C750 D6 serves mission-critical data centers, large hospitals, and industrial campuses where high-power standby is essential.

The QSK23-G3 is a proven platform in the 750-800 kW class, offering a 40,000-hour major overhaul interval that reflects the engine's conservative displacement-to-power ratio. The HPI-PT fuel system provides precise injection control without the complexity of a common rail architecture, resulting in a fuel system that is robust and field-serviceable. CTT turbocharging delivers the boost required for full load acceptance within 10 seconds.

Medium-voltage options (4160V) are available for campus distribution applications. The C750 D6 supports PowerCommand 2.3 and 3.3 controllers for paralleling, enabling multi-genset configurations for N+1 redundancy or phased load growth.

Engineering specifications

Physical

Length: 117 in
Width: 65 in
Height: 77 in
Dry weight: 7,000 lb

Fuel system & runtime

Fuel use @ full load: 52 GPH
Fuel use @ 75% load: 38 GPH
Fuel use @ 50% load: 27 GPH

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GPH

Estimated runtime

5.0 hours(0.2 days)

Fuel consumption ≈ 40.11 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 C750 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 1000 hours
Fuel filter: Every 500 hours
Major overhaul: ≈ 40,000 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.

Component	Symptom	Typical hours	Severity
HPI-PT fuel injection system	Rough running, power loss, injection timing drift	—	moderate
CTT HX82 turbocharger	Reduced boost, excessive smoke, turbo bearing noise	—	moderate
Fuel quality / tank degradation	Filter clogging, hard starting, injector fouling from stagnant fuel	—	moderate
Starting system (24V battery bank)	Slow crank, failed start requirement on infrequently exercised units	—	minor

Frequently Asked Questions

What engine does the Cummins C750 D6 use?: The C750 D6 uses the Cummins QSK23-G3 -- a 23.1-liter, inline-6-cylinder diesel with HPI-PT (Hydraulic Pressure Intensifier - Pre-combustion Technology) fuel injection. This is the same engine family as the C800 D6, at a lower output calibration.
What are the standby and prime ratings of the C750 D6?: Standby rating is 750 kW (938 kVA) at 60 Hz, 0.8 power factor. Prime rating is 680 kW (850 kVA). Both at 1800 rpm, 60 Hz, three-phase.
What are the service intervals for the C750 D6?: Oil and filter changes are due at 500 hours or 12 months. Air filter replacement at 1,000-hour intervals. Fuel filter at 500 hours. Coolant flush at 6,000 hours. Major overhaul interval is 40,000 hours under standard standby duty conditions.
How does the C750 D6 compare to the C800 D6?: Both use the QSK23-G3 engine (23.1L, inline-6, HPI-PT). The C750 D6 is rated at 750 kW standby vs 800 kW for the C800 D6. The C750 D6 runs at a more conservative output, which may provide slightly better fuel economy and longer component life in high-utilization applications.
Can OnPoint Generators service the C750 D6 in Northern California?: Yes. OnPoint Generators provides authorized Cummins service for large commercial diesel generators across the San Francisco Bay Area and Northern California. QSK23 service requires Cummins INSITE diagnostic software for HPI-PT fuel system calibration and ECM programming.

Compatible equipment

Transfer switches

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