Service parts for the 750 DQCB
Grouped by system, with how many of each the parts manual calls for.
Electrical
1 requiredPrices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.
Specifications
| Fuel | Diesel |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 750 kW |
| Emissions | EPA Tier 2 |
| Controller | PowerCommand 2.3 |
| Oil capacity | 102.0 L |
| Voltage options | 277/480 V |
| Phase | 3 |
| Circuit breaker | 1200 A |
| Battery voltage | 24 V |
| Max ambient | 50 °C |
| Dimensions (L×W×H) | 4762×2083×1595 mm |
| Dry weight | 2262 kg |
| Sound level | 91.1 dBA @ 7 m |
Engine
| Oil capacity | 102.0 L |
|---|---|
| Coolant capacity | 109.5 L |
| Displacement | 23.15 L |
| Aspiration | Turbocharged and low temperature after-cooled |
| Rated speed | 1800 rpm |
Filters for the Cummins/Onan QSK23-G7 NR2
2Engine-mounted filters the filter manufacturers list for this engine family. These come from the engine, not from this generator set’s own parts list, so confirm against your serial number before ordering.
| System | Filter | Description | Cross-references | |
|---|---|---|---|---|
| Fuel / water separator | P552006 | Fuel Filter, Water Separator Spin-On Twist&Drain | CUMMINS 3089916, CUMMINS 4095189, NAPA 3645, BALDWIN BF1262 | FridayParts $42.88 |
Listed for this engine in only one kind of machine, so they may depend on how the engine was installed:
| System | Filter | Description | Cross-references | |
|---|---|---|---|---|
| Oil filter | P551670 | Lube Filter, Spin-On Full Flow | CUMMINS 298670, CUMMINS 299670, NAPA 1970, CARBOCOL 0026 | FridayParts $26.68 |
Same engine, other brands
1 brandThe Cummins/Onan QSK23-G7 NR2 in this set also powers 2 generator sets sold under 1 other brand. Service parts and maintenance intervals for the engine are shared; enclosure, alternator, controller and ratings are not.
| Brand | Models |
|---|---|
| MQ Power | 800kW Containerized Diesel Generator Set, CG800C2 |
Maintenance & consumables
for the Cummins/Onan QSK23-G7 NR2| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Dry, Dual Element | — | 500 hr | ||
| Fuel filter | 30 micron Racor ® fuel/water separator filter | — | 500 hr | ||
| Oil filter | 4 Spin-on, Full Flow | — | 500 hr | ||
| Battery | 10Amp, 120/208/240VAC, 12/24V, 50/60Hz | A048G602 | 500 hr | eBay | |
| Belt | Belt Driven, Centrifugal | — | |||
| Coolant | -45 | 109.5 | — | ||
| Oil | Oil level is full | 102.0 | — | ||
| Spark plug | not specified | — |
Service specifications
13| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Speed | Droop electronic speed governing | 0 to 10 | % | no load to full load |
| Speed | Frequency drift | +/-0.5 | % | 33 °C (60 °F) change in ambient temperature over an 8 hour period |
| Speed | Isochronous governing steady state accuracy | +/-0.25 | % | any steady state load from no load to full load |
| Speed | Over frequency shutdown/warning (81 o) default | 6 | Hz | 20 seconds, disabled |
| Speed | Under frequency shutdown (81 u) default | 6 | Hz | 10 seconds |
| Temperature | Control operating ambient temperature | -40 to +70 | °C | |
| Temperature | HMI operating ambient temperature | -20 to +70 | °C | |
| Voltage | Digital output voltage regulation | +/-1.0 | % | any loads between no load and full load |
| Voltage | Droop voltage regulation | 0-10 | % | no load to full load |
| Voltage | High AC voltage shutdown (59) default | 110 | % | 10 seconds |
| Voltage | Low AC voltage shutdown (27) default | 85 | % | 10 seconds |
| Voltage | Voltage drift | +/-1.5 | % | 40 ºC (104 ºF) change in temperature in an eight hour period |
| Voltage | Voltage overshoot on engine starting or sudden load acceptance | 5 | % | maximum overshoot over nominal level |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Fault codes
4| Code | Name | Meaning | Severity | Action |
|---|---|---|---|---|
| 27 | Low AC voltage shutdown | Voltage on any phase has dropped below a preset value. Adjustable over a range of 50-95% of reference voltage, time delay 2-20 seconds. Default value is 85% for 10 seconds. Function tracks reference voltage. | Shutdown | |
| 59 | High AC voltage shutdown | Output voltage on any phase exceeds preset values. Time to trip is inversely proportional to amount above threshold. Values adjustable from 105-125% of nominal voltage, with time delay adjustable from 0.1-10 seconds. Default value is 110% for 10 seconds. | Shutdown | |
| 81 o | Over frequency shutdown/warning | Generator set is operating at a potentially damaging frequency level. Settings are adjustable from 2-10 Hz above nominal governor set point for a 1-20 second time delay. Default: 6 Hz, 20 seconds, disabled. | Warning | |
| 81 u | Under frequency shutdown | Generator set output frequency cannot be maintained. Settings are adjustable from 2-10 Hz below reference governor set point, for a 5-20 second time delay. Default: 6 Hz, 10 seconds. | Shutdown |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Voltage reconnection
| Voltage | Phase | Connection | Leads | Notes |
|---|---|---|---|---|
| 277/480 | 3 | Wye | 4 Wire | Voltage-277/480, 3 Phase, Wye, 4 Wire |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Common questions
What size generator is the Cummins/Onan 750 DQCB?
The Cummins/Onan 750 DQCB is rated 750 kW standby.
What engine is in the Cummins/Onan 750 DQCB?
The Cummins/Onan 750 DQCB is powered by the Cummins/Onan QSK23-G7 NR2 engine.
Is the Cummins/Onan 750 DQCB diesel or gas?
The Cummins/Onan 750 DQCB runs on Diesel.
How much oil does the Cummins/Onan 750 DQCB take?
The Cummins/Onan QSK23-G7 NR2 engine in the Cummins/Onan 750 DQCB has an oil capacity of 102.0 liters.
What is the coolant capacity of the Cummins/Onan 750 DQCB?
The Cummins/Onan 750 DQCB cooling system holds 109.5 liters (28.9 US gallons) for the engine, per the manufacturer specification sheet.
What is the sound level of the Cummins/Onan 750 DQCB?
The Cummins/Onan 750 DQCB is rated at 91.1 dBA at 7 m, per the manufacturer specification sheet.
How much does the Cummins/Onan 750 DQCB weigh?
The Cummins/Onan 750 DQCB has a dry weight of 2262 kg (4986 lb).
What voltages is the Cummins/Onan 750 DQCB available in?
The Cummins/Onan 750 DQCB is offered in 277/480 V, 3-phase.
Troubleshooting
1Symptoms & remedies
| Symptom | Remedy |
|---|---|
| Output voltage on any phase exceeds preset values | Time to trip is inversely proportional to amount above threshold. Values adjustable from 105-125% of nominal voltage, with time delay adjustable from 0.1-10 seconds. Default value is 110% for 10 seconds. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Parts
10| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 501-0876 | Line, Fuel Cooler Return (Bearward Cooling System, not shown) | 1 | Hose | Amazon eBay |
| 501-0877 | Line, Fuel Supply (Engine Accessories group) | 1 | Hose | Amazon eBay |
| 501-0892 | Line, Fuel Cooler Supply (Bearward Cooling System, not shown) | 1 | Hose | Amazon eBay |
| 503-1675 | Hose, Reducer (Air Cleaner group) | 1 | Hose | Amazon eBay |
| 503-2754-01 | Hose, Oil | 1 | Hose | Amazon eBay |
| A053A190 | Hose, Oil (Valve group) | 1 | Hose | Amazon eBay |
| A055E534 | Switch, Level (low coolant level warning) | 1 | Sensor | Amazon eBay |
| A059Z452 | Seal, O Ring (Valve group) | 1 | Seal | Amazon eBay |
| AF2559300 | Air Cleaner replacement element (Nelson), for Air Cleaner Housing 140-3737 | 1 | Air filter | Amazon eBay |
| 140-1548 | Indicator, Service | 1 | Service part / kit | Amazon eBay $49.99 NAPA $32.16 |
Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.
Available documents
This page was generated from the 3 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.