Open-frame petrol generator set
A fixed-speed petrol set on a tube frame with no acoustic case. The cheapest way to put 230 V sockets on a site where noise is not restricted and the load is mostly resistive.
Features
- Runs at a constant 3 000 rpm for 50 Hz, so frequency drifts a little with load — acceptable for lights, heaters and most hand tools.
- The open frame makes the engine easy to service and easy to damage; specify a full roll cage rather than a bare cradle for hire duty.
- Sound pressure sits roughly 8 to 12 dB(A) above a cased set of the same output.
- Voltage regulation is either by capacitor or by a basic automatic voltage regulator — ask which, because a capacitor machine will not hold volts through an inductive start.
- Recoil start is common at this size; the electric-start version adds a battery to the maintenance list.
Specifications
| Figure | Typical range | Unit | Why it matters |
|---|---|---|---|
| Rated continuous output | 2.0 - 8.0 | kVA | The working figure; peak ratings last seconds. |
| Voltage regulation method | capacitor / AVR | Decides whether the set can start a motor at all. | |
| Sound pressure at 7 m | 72 - 82 | dB(A) | Often the reason an open-frame set is refused on site. |
| Fuel tank capacity | 12 - 30 | l | Sets the refuel interval. |
| Dry weight | 40 - 110 | kg | Determines how it gets moved and lifted. |