Power Factor Correction. Technique of increasing the power factor of a power supply. Switching power supplies without power factor correction draw current in short, high-magnitude pulses. These pulses can be smoothed out by using active or passive techniques. This reduces the input rms current and apparent input power, thereby increasing the power factor.
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This originally referred to the fact that an inductive load, where the current and the voltage are not totally in phase, draws instantaneous power of the instantaneous current times the instantaneous voltage. However, it has been extended to mean any distortion or phase shift in the power drawn from the mains. An AC power supply must use some method to control the power coming from the mains. Usually this is done with some kind of pulsing. There are also components in the power supply that cannot draw current until the voltage gets high enough, or draw current only at the peak of the sine wave. Drawing power from different parts of the sine wave can distort what is left for everybody else to use and the utilities have to compensate for it. In Europe, where the utilities are mostly owned by the government the governments are tempted to use the power of the law to benefit their industries, and have required an increasingly onerous set of PFC values over the years, now requiring PFC for power supplies as low as 75 watts. In the USA the utilities are at the mercy of their customers and PFC requirements have lagged behind Europe.
"Power Factor Correction" is a feature of a power supply whereby it compensates itself to appear as a mainly resistive load to the mains supply in order to smooth the demands that it makes on the supply. PFC is generally more of a benefit for power generation companies than end users, however users that run many computers from a single supply could benefit from using PFC enabled power supplies. More and more countries are imposing legislation that make PFC enabled equipment a requirement.
Power Factor Correction. Electricity supply require that the companies require that the power factor at which the supply is used shall be maintained at not less than 0.9 lagging, on average between one meter reading and the next. For any given wave shape, the power factor is defined as the ratio of Watts/(volts rms x ampsrms) Low power factors increase the KVa demand from the supply, reduces the useful load that can be safely handled by the cables and distribution equipment, and in some cases can attract additional tariff penalties. Lamp circuits which incorporate a choke, leakage reactance transformer, or an electronic ballast can have low power factors, often between 0.3 and 0.6. Low power factor from these circuits can be corrected by the addition of a compensation capacitor. These can be placed at the central point of the supply, locally for each group of luminaries , or integral within each luminaire.
power factor correction. increases the portion of the ac input energy that an ac-input power supply can use, thus increasing overall efficiency
Power Factor Correction. An active or passive input circuit to change the power factor of the input current to a device so that it is closer to a PF of 1.0. Numerous benefits include reduced input line current and lower input harmonics.