Differences between kW and kVA

kW and kVA are units of power. kW stands for kilo-watts and kVA stands for kilo-volts ampere. Let’s see what is the difference between kW and kVA and how to calculate each one of them.

Comparison of kW and kVA

kW – KilowattskVA – Kilo-volt amperes
It is the unit of electric power – In AC system, it is the unit of measure of true power or useful power.kVA is the unit of apparent power in an AC electric system.
It is basically the measure of true power consumed by the load.kVA is basically the amount of power that alternators, transformers and UPS are capable of delivering the load connected to them.
Kilowatts proportional to load power factor.kVA is independent of load power factor.
Motors, lamps, home appliances etc are rated in kW.Alternators, transformers, inverters, UPS etc are rated in kVA.

The below pictures shows the nameplate details of an induction motor which is rated in kW and a transformer rated in kVA.

Motor Nameplate - kW and kVA
Motor nameplate
kVA rating of transformer with nameplate
Transformer nameplate

Calculation of kW – True Power

Single phase kilowatts,

For single phase, kW can be calculated using the following formula.

Single phase – kW = (Voltage X Current X Power factor)/1000

Three-phase kilowatts

For three-phase, kW can be calculated using the following formula.

Three phase kW if line to line voltage is known,

kW = (√3  X Voltage X Current X Power factor)/1000

= (1.732 X Voltage X Current X Power factor)/1000

Three phase kW if phase to phase voltage is known,

kW = (3  X Voltage X Current X Power factor)/1000

Calculation of kVA – Apparent power

Single-phase kVA

For single phase, kVA can be calculated using the following formula.

kVA = (Voltage X Current)/1000

Three-phase kVA

For three phase, kVA can be calculated using the following formula.

Three phase kVA if line to line voltage is known,

kVA = (√3 X Voltage X Current )/1000 = (1.732 X Voltage X Current)/1000

Three phase kVA if phase to phase voltage is known,

kVA = (3 X Voltage X Current)/1000

How to convert kilo-volt-ampere to kilowatt?

To convert kVA to kW, multiply the KVA to the power factor of the circuit.

kW = KVA X P.F(Power factor)

How to convert kW to kVA?

To convert kW to kVA, divide the KVA to the power factor of the load.

kW = KVA / P.F(Power factor)

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