Cummins · Cummins D6 Commercial Diesel

Cummins C1500 D6

1500 kW standby / 1365 kW prime · Diesel · Liquid-cooled

1500 kW diesel standby generator with QSK50 50.3L V-16 engine and MCRS fuel injection. EPA Tier 2 compliant, PowerCommand control, 2P2L cooling, for data center, hospital, and mission-critical standby applications.

Cummins Cummins C1500 D6 generator — specifications and details
Standby power
1500 kW / 1365 kW prime
Voltage options
277/480V, 346/600V, 4160V, 12470V, 13200V, 13800V
Frequency / Phase
60 Hz · 3-phase
Engine
Cummins QSK50 · 50.3L
EPA / Emissions
Tier 2
Data CentersHealthcareManufacturingCommercialparalleling-array
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Overview#

The Cummins C1500 D6 is a 1500 kW (1.5 MW) standby diesel generator set powered by the QSK50 -- a 50.3-liter, V-16 diesel engine with Cummins' Modular Common Rail System (MCRS) fuel injection. Rated at 1875 kVA standby and 1706 kVA prime at 60 Hz, the C1500 D6 is the largest single-engine generator in Cummins' D6 commercial diesel lineup and one of the most powerful single-genset solutions available in the North American market.

The QSK50 V-16 delivers nearly 1.9 MVA of apparent power from a single engine-alternator set. The MCRS fuel system provides electronically controlled injection for all 16 cylinders, while the 2P2L cooling system maintains precise thermal management under full load conditions. The 40,000-hour major overhaul interval is outstanding for an engine producing this level of power, reflecting the conservative power-to-displacement ratio that Cummins achieves with 50.3 liters at 1500 kW.

The C1500 D6 is the standard building block for large data center paralleling arrays, where 4-10 units provide 6-15 MW of standby capacity with N+1 redundancy. Medium-voltage options up to 13,800V and PowerCommand 3.3 paralleling controllers are standard for these applications. For sites requiring even more power per unit, Cummins offers the QSK60 and QSK78 platforms above 1500 kW.

Engineering specifications

Physical

Length
184 in
Width
97 in
Height
122 in
Dry weight
16,373 lb

Fuel system & runtime

Fuel use @ full load
110 GPH
Fuel use @ 75% load
77 GPH
Fuel use @ 50% load
56 GPH

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Estimate runtime for the Cummins C1500 D6

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

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Estimated runtime

2.4 hours(0.1 days)

Fuel consumption ≈ 84.86 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 C1500 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.

ComponentSymptomTypical hoursSeverity
MCRS fuel injection systemInjector fault codes, rough running, power imbalance between banks—moderate
Turbocharger(s) (HX82/HX83)Reduced boost, excessive smoke, turbo bearing noise—moderate
2P2L cooling systemCoolant temperature exceedances, system pressure loss in either loop—severe
Fuel quality / tank degradationFilter 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 C1500 D6 use?
The C1500 D6 uses the Cummins QSK50 -- a 50.3-liter, V-16 diesel engine with Modular Common Rail System (MCRS) fuel injection. The QSK50 is Cummins' largest current-production power generation engine, delivering 1500 kW standby at the top of the D6 diesel range.
What are the standby and prime ratings of the C1500 D6?
Standby rating is 1500 kW (1875 kVA) at 60 Hz, 0.8 power factor. Prime rating is 1365 kW (1706 kVA). Both at 1800 rpm, 60 Hz, three-phase.
What are the service intervals for the C1500 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 C1500 D6 compare to the C1250 D6?
The C1500 D6 uses the QSK50 (50.3L, V-16) while the C1250 D6 uses the QSK38 (37.7L, V-12). The QSK50 is 33% larger in displacement, with 4 additional cylinders. The V-16 is substantially heavier (16,373 lb vs approximately 13,500 lb) and longer (184 in vs 155 in). Choose the C1500 D6 when the load requires it; otherwise the C1250 D6 is more economical to install and maintain.
What cooling system does the C1500 D6 use?
The C1500 D6 uses Cummins' 2P2L (2-pump, 2-loop) cooling system, which separates the jacket water circuit from the charge air cooling circuit. At 1500 kW, thermal management is critical -- the 2P2L system provides independent temperature control for each circuit.
Can OnPoint Generators service the C1500 D6 in Northern California?
Yes. OnPoint Generators provides authorized Cummins service for large diesel generators across the San Francisco Bay Area and Northern California. QSK50 V-16 engines require specialized tooling for service access on the inboard cylinders. We maintain full Cummins INSITE diagnostic capability for MCRS calibration and cylinder contribution analysis.

Compatible equipment

Transfer switches

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