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Cummins Onan GFLB Specs (Power | Fuel Consumption)

Written by Ernie Lo in Specs Last Updated August 18, 2026

The Cummins Onan GFLB generator is listed with standby output of 650 kW, natural gas fuel, 60 Hz operation, 8 available voltage configurations, and Three phase.

Cummins Onan Generator Specifications

Generator • natural gas • 60 Hz • Three phase

Standby power: 650 kWVoltage options: 8 configurationsDry weight: 22,736 lb (10,313 kg)

Key specifications

650 kW Standby power
natural gas Fuel
8 configurations Voltage options
Three phase Phase
22,736 lb (10,313 kg) Dry weight
60 Hz Frequency

Useful generator charts

Charts are shown only when this model has enough usable source data.

Power-to-weight
Standby output per 1,000 lb of dry weight versus similar-output Cummins Onan models.
This model

28.6 kW

Peer average

58 kW

16th percentile
Power output
Low 650 kW High 650 kW
Standby

650 kW

Prime

650 kW

Model spec snapshot
Representative numeric specifications from this generator.
650 kWStandby
22,736.27 lbWeight

How the Cummins Onan GFLB compares

This compares the supplied numeric specification with Cummins Onan generators in the same broad standby-power class where enough comparable data exists.

Standby power
650 kW
In line with avg
47th percentile
Dry weight
22,736 lb
47% above avg
89th percentile
Oil capacity
53.89 gal
100% above avg
97th percentile
Standby power650 kW
Low 400 kWAverage 665.2 kWHigh 921.6 kW

Very close to the similar-output Cummins Onan average. Around the 47th percentile for this field.

Dry weight22,736 lb
Low 4,643 lbAverage 15,485 lbHigh 39,573 lb

About 47% above the similar-output Cummins Onan average. Around the 89th percentile for this field.

Oil capacity53.89 gal
Low 8.83 galAverage 27 galHigh 54.53 gal

About 100% above the similar-output Cummins Onan average. Around the 97th percentile for this field.

This model Peer average

Generator information

Manufacturer Cummins Onan
Model GFLB
Generator type Generator
Fuel natural gas
Frequency 60 Hz

Electrical output

Standby power 650 kW
Prime power 650 kW
Standby kVA 813.0
Voltage options 120/208 V, 127/220 V, 139/240 V, 220/380 V, 240/416 V, 254/440 V, 277/480 V, 347/600 V
Phase Three phase
Power factor 0.8

Engine, cooling and controls

Engine model Cummins/Onan GTA50G2
Engine displacement 3, 051 cu in (50 L)
Aspiration / cooling Turbocharged & Aftercooled
Rated engine speed 1800 rpm
Engine oil capacity 53.9 gal (204 L)
Oil capacity 53.9 gal (204 L)
Coolant capacity 86.1 gal (326 L)
Maximum ambient 167 °F (75 °C)
Controller PowerCommand 3.3, PowerCommand digital electronic
Alternator Cummins/Onan Revolving field, single bearing, 4-pole, brushless, drip-proof construction
Emissions EPA SI NSPS Compliant Capable

Physical specifications

Dry weight 22, 736 lb (10, 313 kg)
Dimensions (L × W × H) 204 × 99 × 108 in (5182 × 2515 × 2744 mm)

Battery

Battery group 8D
Battery cranking 1000 CCA
Battery voltage 24 V
Battery quantity 4

Fuel consumption

Standby 0%; 1%
Prime 100%

Disclaimer: Specifications should be verified against the official owner’s or service manual and confirmed on the Cummins North America generator website.

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Ernie Lo

Ernie Lo is a qualified web designer and web developer. He works as an IT support technician and website manager at Benleigh Vending, and he also fixes vending machines.

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