How to Calculate Amps From Kw
- 1). Calculate current in amps from power in kilowatts in a simple circuit by dividing the power by the voltage. For example, if the direct-current power source is a battery with nine volts and the power is 0.001 kW, then the current is 9V / 0.001kW = 9V / 1W = 9 amps.
- 2). Determine the current if you know the circuit's resistance instead of its voltage by using the formula P=I^2*R, where "^2" means "squared." For example, if a battery of unknown voltage connects to a single-loop circuit with 5 ohms of resistance, producing 0.05 kW of power, then the current is the square root of 50W / 5 ohms, or 3.16 amps after rounding.
- 3). Determine the current for a single-phase alternating circuit with the formula 1,000 * (power in kW) / [voltage * power factor]. The power factor accounts for inductance in the circuit that stores energy and returns it back into the circuit. A good estimate for the power factor of a residential home is around 0.85.
- 4). Determine the current for a three-phase alternating circuit with the formula 1,000 * (power in kW) / [voltage * power factor * √3]. (ref. 3) √3 equals 1.73, after rounding. Three-phase AC is how most electricity is delivered throughout the world.
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