In electrical and electronic design, it helps to know how much power a device consumes, whether you measure power in watts or kilovolt-amps, also called KVA. For direct current (DC) circuits, calculating watts is simple: you multiply a circuit's voltage by the amps of current. For circuits and equipment that use AC, or alternating current, the calculation is more complicated. Because AC voltage and current peak at different moments, you use a quantity called the power factor. An ideal AC device has a power factor of 1; many real devices range between .6 and .95. To convert watts to KVA, multiply watts by a device's power factor.
Instructions
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1
Key the watts consumed by a circuit into your calculator. For example, an electric motor with a power factor of .87 uses 110 volts and 2 amps of current. So, 110 volts times 2 amps equals 220 watts.
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2
Divide the watts by 1,000 to get kilowatts. In this example, 220 watts / 1,000 equals .22 kilowatts.
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Multiply the kilowatts by the power factor and press the "Equals" key to obtain the final result in KVA. Since the motor's power factor is .87, you multiply .22 kilowatts by .87 to obtain .19 KVA.
