oviding optimum performance, reliability, and
versatility for standby operation in stationary applications.
A primary feature of the GGDB GenSet is strong motor
starting capability and fast recovery from transient load
changes. The GGDB torque matched system includes a
heavy-duty Ford 4-cycle liquid cooled spark ignited
engine, an AC alternator with high motor starting
capacity, and an electronic voltage regulator for precise
regulation under steady-state or transient loads. The
GGDB GenSet accepts 100% of the nameplate standby
rating in one step, in compliance with NFPA110
requirements.
An LP vapor fuel system is standard with several options
for natural gas and LP liquid as well as dual fuel.
The GGDB GenSet offers both user and environment
friendly operation. The standard two wire remote control
system provides for automatic remote operation and
automatic shutdown for fault detection. Controls may be
upgraded to the Detector
TM
Control for NFPA110
compliance.
A wide range of options, accessories, and services are
available, allowing configuration to your specific power
generation needs.
Every production unit is factory tested at rated load and
power factor. This testing includes demonstration of
rated power and single-step rated load pickup. Cummins
Onan manufacturing facilities are registered to ISO9001
quality standards, emphasizing our commitment to high
quality in the design, manufacture, and support of our
products. The GenSet is CSA certified.
All Cummins Onan brand power generation systems are
backed by a comprehensive warranty program and
supported by a worldwide network of 170 distributors and
service branches, to assist you with warranty, service,
parts, and planned maintenance support.

Ford Heavy-Duty Gas Engine - Rugged 4-cycle
industrial spark-ignited engine delivers reliable power.
The electronic governor provides fast response to load
changes.

Electronic voltage regulator - Torque-matched
regulator provides fast recovery from transient load
changes, underfrequency compensation, and precise
regulation.

Alternator - Several alternator sizes offer selectable
motor starting capability with low reactance 2/3 pitch
windings, low waveform distortion with non-linear loads
and fault clearing short-circuit capability.

Control systems - The standard 2-wire remote control
system provides capability for automatic remote starting
and stopping, and fault protection features. Upgrade to
the Detector
TM
Control for NFPA110 compliance.

Cooling systems - Standard cooling package provides
reliable running up to 40
o
C ambient temperature.
Optional remote cooling capability is offered.

Integral Vibration Isolation - Robust skid base
supports the engine, alternator, and radiator on
isolators, minimizing transmitted vibration.

E-Coat Finish - Dual electro-deposition paint system
provides high resistance to scratches, corrosion, or
fading.

Housings - Optional weather proof and sound
attenuated enclosures are available.

Certifications - Generator sets are designed,
manufactured, tested, and certified to relevant UL,
NFPA, ISO, IEC, and CSA standards.

Warranty and Service - Backed by a comprehensive
warranty and world wide distributor network. .
© 2000 Onan Corporation Specifications subject to change without notice S-1175
Generator Set
The general specifications in this document provide representative configuration details, but the outline drawing
must be used for installation design.
See outline drawing 500-3194 for installation design specifications.
Unit Width, in.(mm)
26.0 (660)
Unit Height, in.(mm)
39.9 (1013)
Unit Length, in.(mm)
64.0 (1626)
Unit Dry Weight, lbs. (kgs)
847 (384)
Unit Wet Weight, lbs. (kgs)
880 (399)
Rated Speed, rpm
1800
Voltage Regulation, No Load to Full Load
±2.0%
Random Voltage Variation
±1.0%
Frequency Regulation
Isochronous
Random Frequency Variation
±0.3% @ 60Hz, ±0.8% @ 50Hz
Radio Frequency Interference
Meets requirements of most industrial and commerical applications
Natural Gas
Propane
Cooling
Standby
Standby
Fan Load, HP (kW)
2.2 (1.6)
2.2 (1.6)
Coolant Capacity with radiator, US Gal (L)
3.0 (11.4)
3.0 (11)
Coolant Flow Rate, Gal/min (L/min)
18.8 (71.2)
18.8 (71)
Heat Rejection To Coolant, Btu/min (MJ/min)
1200.0 (1.3)
1200 (1.3)
Heat Radiated To Room, Btu/min (MJ/min)
638.0 (0.7)
638 (0.7)
Air
Combustion Air, cfm (m
3
/min)
65.0 (1.8)
65.0 (1.8)
Alternator Cooling Air, cfm (m
3
/min)
250.0 (7.1)
250.0 (7.1)
Radiator Cooling Air, scfm (m
3
/min)
2690.0 (76.1)
2690.0 (76.1)
Minimum Air Opening to Room, ft
2
(m
2
)
3.9 (0.4)
3.9 (0.4)
Minimum Discharge Opening, ft
2
(m
2
)
2.6 (0.2)
2.6 (0.2)
Max. Static Restriction, in H
2
O (Pa)
0.2 (62.5)
0.2 (62.5)
Rating Definitions
Standby Rating based on: Applicable for supplying emergency power for the duration of normal power interruption. No
sustained overload capability is available for this rating. (Equivalent to Fuel Stop Power in accordance with ISO3046, AS2789,
DIN6271 and BS5514). Nominally rated.
Prime (Unlimited Running Time) Rating based on: Applicable for supplying power in lieu of commercially purchased
power. Prime power is the maximum power available at a variable load for an unlimited number of hours. A 10% overload
capability is available for limited time. (Equivalent to Prime Power in accordance with ISO8528 and Overload Power in
accordance with ISO3046, AS2789, DIN6271, and BS5514). This rating is not applicable to all generator set models.
Base Load (Continuous) Rating based on: Applicable for supplying power continuously to a constant load up to the full
output rating for unlimited hours. No sustained overload capability is available for this rating. Consult authorized distributor for
rating. (Equivalent to Continuous Power in accordance with ISO8528, ISO3046, AS2789, DIN6271, and BS5514). This rating
is not applicable to all generator set models.
Site Derating Factors
Natural Gas
Engine power available up to 3500 ft (1067 m) at ambient temperatures up to 85°F (29°C). Above 3500 ft (1067 m) derate at
5% per 1000 ft (305 m), and 1% per 10°F (2% per 11°C) above 85°F (29°C).
Propane
Engine power available up to 6000 ft (1829 m) at ambient temperatures up to 85°F (29°C). Above 6000 ft (1829 m)
derate at 4% per 1000 ft (305 m), and 1% per 10°F (2% per 11°C) above 85°F (29°C). .
© 2000 Onan Corporation Specifications subject to change without notice S-1175
Engine
Rugged Ford
®
spark ignited engines are designed to operate efficiently on gaseous fuels. Fuel system options
available for natural gas, LP vapor, and LP liquid. In addition, for extra system reliability combination natural gas/LP
vapor or natural gas/LP liquid with automatic changeover are available.
Electronic governing provides precise speed regulation, especially useful for applications requiring constant
(isochronous) frequency regulation such as Uninterruptible Power Supply systems, non-linear loads, or sensitive
electronic loads. Optional coolant heaters are recommended for all emergency standby installations or any
application requiring fast load acceptance after start-up.
Specifications Engine
Base Engine
Ford Model LRG-425I, naturally aspirated
Displacement in
3
(L)
150.0 (2.5)
Overspeed Limit, rpm
2500 ±50
Cylinder Block Configuration
Cast iron, In-line 4 cylinder
Cranking Current
150 amps at ambient temperature of 32°F (0°C)
Battery Charging Alternator
95 amps
Starting Voltage
12-volt, negative ground
Lube Oil Filter Types
Spin-on, full flow
Cooling System
104
o
F (40
o
C) ambient cooling system
Standard Fuel
LP vapor is standard. Optional LP liquid, natural gas, LP liquid/natural gas and LP vapor/natural
gas
Natural Gas
Propane
Power Output
Standby
Standby
Gross Engine Power Output, bhp (kWm)
40.0 (29.8)
42.0 (31.3)
BMEP, psi (kPa)
105.0 (723.9)
105.0 (723.9)
Bore, in. (mm)
3.74 (95.0)
3.74 (95.0)
Stroke, in. (mm)
3.40 (86.4)
3.40 (86.4)
Piston Speed, ft/min (m/s)
1021.0 (5.2)
1021.0 (5.2)
Compression Ratio
9.4:1
9.4:1
Lube Oil Capacity, qt. (L)
4.5 (4.3)
4.5 (4.3)
Fuel Flow
Minimum Operating Pressure, in. H
2
O (kPa)
7.0 (1.7)
7 (2)
Maximum Operating Pressure, in. H
2
O (kPa)
13.6 (3.4)
14 (3)
Air Cleaner
Maximum Air Cleaner Restriction, in. H
2
O (kPa)
15.0 (3.7)
15.0 (3.7)
Exhaust
Gas Flow (Full Load), cfm (m
3
/min)
210.0 (5.9)
210.0 (5.9)
Gas Temperature,
o
F (
o
C)
1250 (677)
1250 (677)
Maximum Back Pressure, in. H
2
O (kPa)
41.0 (10.2)
41.0 (10.2)
Fuel Consumption - Natural Gas
Standby
60 Hz Ratings, kW (kVA)
20.0 (25.0)
Load
1/4
1/2
3/4
Full
cfh
122.0
163.0
201.0
252.0
m
3
/hr
461.8
617.0
760.8
953.8
Fuel Consumption - Propane
Standby
60 Hz Ratings, kW (kVA)
20.0 (25.0)
Load
1/4
1/2
3/4
Full
cfh
44.0
64.0
74.0
84.0
m
3
/hr
1.2
1.8
2.1
2.4 .
© 2000 Onan Corporation Specifications subject to change without notice S-1175
Alternator
Single-bearing alternators couple directly to the engine flywheel with flexible discs for drivetrain reliability and
durability. No gear reducers or speed changers are used. Two-thirds pitch windings eliminate third-order
harmonic content of the AC voltage waveform and provide the standardization desired for paralleling of generator
sets. The excitation system is a self (shunt) excited system with the voltage regulator powered directly from the
generator set output. The standard alternator is a single phase 4 lead, 105
o
C rise. Optional alternators include 3
phase and 3 phase with full single phase output capab