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.
The key differences between kW and kVA
| kW – Kilowatts | kVA – 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 is 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 that is rated in kW and a transformer rated in kVA.
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 by 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 by the power factor of the load.
kW = KVA / P.F(Power factor)
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