Why Generators are rated in kVA instead of kW?
Answer:
Generators are rated in kVA instead of kW because they measure different aspects of the power output. kW is the real power that a generator can supply based on its engine’s horsepower.
kVA is the apparent power that a generator can supply if it was 100% efficient. The power factor is the ratio of kW to kVA, and it indicates the electrical efficiency of the system.
To convert between kW and kVA, you need to know the power factor of the generator
The reason why generators are rated in kVA instead of kW is that kVA takes into account both active and reactive power, while kW only takes into account active power.
Generators are designed to deliver both active and reactive power, which depends on the power factor of the connected load.
The conductors of a generator are calculated for a definite current and the insulation at the magnetic system are designed for a definite voltage independent of P.F. (Cos Φ) of the load.
For this reason apparent power measured in kVA is regarded as the rated power of the generator.