Cummins
Cummins 4B3.9-G12
B3.9 Series
The Cummins 4B3.9-G12 is a 3.9-litre inline-4 diesel engine for generator sets, rated at 38 kVA / 30 kWe standby power at 1,500 RPM (50 Hz). It is a liquid-cooled engine built in China.
- Standby Power · 50 Hz
- 38 kVA
- Electrical Output
- 30 kWe
- Cylinders
- L4
- Displacement
- 3.9 L
- Rated Speed
- 1,500 / 1,800 RPM
Power Ratings
kWm = mechanical shaft power · kWe = electrical output · kVA = kWe ÷ 0.8 pf
50 Hz1500 RPM
| kWm | kWe | kVA | |
|---|---|---|---|
| Prime Power | 27.8 | 25 | 31.3 |
| Standby Power | 33.3 | 30 | 37.5 |
60 Hz1800 RPM
| kWm | kWe | kVA | |
|---|---|---|---|
| Prime Power | 31.1 | 28 | 35 |
| Standby Power | 38.9 | 35 | 43.8 |
Technical Specifications
| Brand | Cummins |
| Model | 4B3.9-G12 |
| Series | B3.9 Series |
| Configuration | L4 |
| Cylinders | 4 |
| Displacement | 3.9 L |
| Fuel Type | Diesel |
| Ignition Type | Compression Ignition |
| Cooling Method | Liquid-Cooled |
| Emissions Standard | Unregulated |
| Country of Origin | China |
Frequently asked questions
What is the power output of the Cummins 4B3.9-G12?
The Cummins 4B3.9-G12 is rated at 38 kVA standby / 31 kVA prime at 50 Hz (1,500 rpm); and 44 kVA standby / 35 kVA prime at 60 Hz (1,800 rpm).
Does the 4B3.9-G12 run at 50 Hz or 60 Hz?
The Cummins 4B3.9-G12 is available for both 50 Hz (1,500 rpm) and 60 Hz (1,800 rpm).
What fuel does the Cummins 4B3.9-G12 use?
The Cummins 4B3.9-G12 is a diesel generator-set engine.
What is the displacement and cylinder configuration of the 4B3.9-G12?
The Cummins 4B3.9-G12 is an inline-4 (4-cylinder) engine with a displacement of 3.9 L.
Is the Cummins 4B3.9-G12 still in production?
Yes — the Cummins 4B3.9-G12 is a current production model.
Is a datasheet available for the 4B3.9-G12?
Yes — an official Cummins datasheet for the Cummins 4B3.9-G12 can be downloaded from this page.
Related Engines
Compare Cummins 4B3.9-G12
Reference
- Canonical page
- /engines/cummins-4b39-g12
- Last database update
- 2026-05-29
- Manufacturer files
- 1 datasheet linked
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