These calculators will assit you in determining what size generator you may require or how to convert one unit of electricity to another.

Guide to units:
HP = Horsepower
kW = Kilo Watts
kVA = Kilo Volt Amps

I = Ampere or Current
V = Volts
PF = Power Factor

Calculating Ampere (I), given kVA.
1, 2, 3
= Ampere

Converting kVA to kW
kVA = kW
Converting kW to kVA
kW = kVA

Converting kW to HP
kW = HP

What size genset is needed to start a 3 phase electric motor Direct on
Line (DOL) start
HP of
= Generator
kVA Required

Generator Size to Start Motors

Instructions: You only need to fill in the columns coloured in blue.
Fill in the HP of the motor(s) in their starting squence, select the start method (Direct On Line or Star Delta) and press Evaluate. The required generator size will then be displayed at the bottom.

3 Phase (415 volt @ 50Hz)
1 Phase (240 volt @ 50Hz)

Starting Sequence Motor HP Start Method
DOL / StarDelta
Run Variable Phase Current Starting Value Total Run Current Total Start Current
1 /
2 /
3 /
4 /
5 /
6 /
Generator Size for Starting with: kVA*
Generator Size for Running with: kVA*
Generator Size Recommended: kVA*


* Please NOTE the above calculations are an estimate only because other factors such as site conditions, motor efficiencies and iron losses are not taken into consideration.