Three-phase site generator set
A 400 V three-phase set for hoists, mixers, small tower cranes, welders and distribution boards. Specified on starting current rather than running current.
Features
- Direct-on-line motor starting draws five to seven times full-load current, so the set is commonly two to three times the motor's nameplate rating.
- Single-phase loads hung off a three-phase alternator must stay inside the machine's imbalance limit, commonly 20 % of rated current on any one phase.
- Welding sets and variable-speed drives push harmonic current back into the alternator, so a de-rated or oversized machine is normal practice.
- Output is taken through a panel with a main breaker and earth-leakage protection, not through plug sockets.
- The earthing arrangement — earth reference at the set, or a site electrode — has to be decided before delivery, not on the day.
- Alternator insulation class and temperature rise together decide what the set can actually hold at 40 °C ambient.
Specifications
| Figure | Typical range | Unit | Why it matters |
|---|---|---|---|
| Rated continuous output | 10 - 60 | kVA | The base figure for load calculation. |
| Voltage / phase / frequency | 400 / 3~ + N / 50 Hz | V | Must match the site board exactly. |
| Maximum single-phase imbalance | 20 | % | Exceeding it overheats one alternator winding. |
| Alternator insulation class | H | Sets the permitted temperature rise and therefore hot-ambient output. | |
| Motor starting capability | up to 20 direct-on-line, by set size | kW | The figure that decides whether the crane will start. |
| Enclosure protection rating | IP 23 | Whether the set can stand in the open in rain. |