Size a generator for a connected load including starting surge.
Generator sizing is usually governed by motor starting surge rather than running load. Sizing on running load alone leaves the set unable to start its largest motor. Running a generator below about 30 per cent load causes wet stacking in diesels, so oversizing creates its own maintenance problems.
Generator Size
Generator kVA = max(running kVA × 1.25, starting kVA) ÷ (1 − derating)
Generator kVA = max(running kVA × 1.25, starting kVA) ÷ (1 − derating) Generator sizing is usually governed by motor starting surge rather than running load. Sizing on running load alone leaves the set unable to start its largest motor.
Running a generator below about 30 per cent load causes wet stacking in diesels, so oversizing creates its own maintenance problems.
This calculator takes 5 inputs: Running load, Largest motor started on load, Motor starting multiple, Load power factor, Derating for site conditions. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.