The most common mistake when sizing is simply adding up nameplate ratings. Real selection has to account for starting current, power factor and the diversity factor.
- kW versus kVA：kVA × 功率因数（通常取 0.8）。 = kVA is apparent power and kW is active power; kW = kVA × power factor (usually taken as 0.8). = kVA × 功率因数（通常取 0.8）。
- Motor loads：Motor starting current can be 5–7 times the rated current, so allow enough margin for the starting method used.
- Diversity factor：Not all loads run at the same time; 0.7–0.9 is a reasonable factor depending on the application.
- Safety margin：We recommend a set rated at 1.1–1.25 times the calculated load, with room for future expansion.
Send us your load list and our engineers will calculate the recommended rating for you.