Technical Terms

The power factor is the ratio of the apparent power flowing in a circuit to the real power consumed by the load in an AC power system. It means the efficiency of AC power.

When a device such as a motor is operated, the power required during operation (real power) is smaller than the product of the Root Mean Square (RMS) voltage and RMS current as the apparent power. This is due to the coils (inductive loads) and capacitors (capacitive loads) built into the equipment. It is caused by reactive power that is not consumed simply because of the round trip between the load and the AC power source.

In other words, the higher the power factor, the more efficient the equipment. The power factor is measured by a power factor meter or similar devices. The power factor in an ordinary household is considered as about 85%. As of high-voltage power receiving facilities (cubicles), etc., the rate will be 90% to 99%.

Power factor | Technical Terms: Power Supplies | Matsusada Precision

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