Cummins
Cummins 4BT3.9-G1
B3.9 Series
The Cummins 4BT3.9-G1 is a 3.9-litre inline-4 diesel engine for generator sets, rated at 50 kVA / 40 kWe standby power at 1,500 RPM (50 Hz). It is a liquid-cooled engine built in China.
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- Manufacturer files
- 1 datasheet
- Last updated
- 2026-05-29
- Package route
- diesel generator sets
- Standby Power · 50 Hz
- 50 kVA
- Electrical Output
- 40 kWe
- Cylinders
- L4
- Displacement
- 3.9 L
- Rated Speed
- 1,500 RPM
Power Ratings
kWm = mechanical shaft power · kWe = electrical output · kVA = kWe ÷ 0.8 pf
50 Hz1500 RPM
| kWm | kWe | kVA | |
|---|---|---|---|
| Prime Power | 35.6 | 32 | 40 |
| Standby Power | 44.4 | 40 | 50 |
Cummins 4BT3.9-G1 generator set context
The Cummins 4BT3.9-G1 is listed here as a diesel generator-drive engine for 50 Hz generator sets, with a headline 50 kVA / 40 kWe / standby rating. Use this page to compare the published engine output, electrical kWe/kVA ratings, emissions level, datasheet availability, and neighboring models before specifying an alternator, controller, enclosure, voltage, and compliance package.
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Technical Specifications
| Brand | Cummins |
| Model | 4BT3.9-G1 |
| 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 4BT3.9-G1?
The Cummins 4BT3.9-G1 is rated at 50 kVA standby / 40 kVA prime at 50 Hz (1,500 rpm).
Does the 4BT3.9-G1 run at 50 Hz or 60 Hz?
The Cummins 4BT3.9-G1 is rated for 50 Hz (1,500 rpm).
What fuel does the Cummins 4BT3.9-G1 use?
The Cummins 4BT3.9-G1 is a diesel generator-set engine.
What is the displacement and cylinder configuration of the 4BT3.9-G1?
The Cummins 4BT3.9-G1 is an inline-4 (4-cylinder) engine with a displacement of 3.9 L.
Is the Cummins 4BT3.9-G1 still in production?
Yes — the Cummins 4BT3.9-G1 is a current production model.
Is a datasheet available for the 4BT3.9-G1?
Yes — an official Cummins datasheet for the Cummins 4BT3.9-G1 can be downloaded from this page.