Why are Transformers Rated in kVA and Motors in kW?
TRANSFORMER = KVA (kilovolt-amperes)
A transformer does not use power; instead, it transfers it.
It provides both
- Active (kW) power and
- Reactive (KVAR) power,
but the power factor is determined by the load rather than the transformer.
That is why transformers are rated in kVA, that represents the overall perceived power capacity, independent of how the power is distributed.
CALCULATOR: How to calculate the kVA Size of a Single Phase & Three Phase Transformer?
MOTOR = kW (kilowatts)
Motor’s used to convert electrical power to mechanical power, with a focus on real, useable power (kW).
Because motors are the primary power consumers, the power factor influences their performance and efficiency.
So they’re rated in kW since that’s what does the work.
CALCULATOR: Motor Efficiency Calculator