PFC stands for Power Factor Correction. The purpose of PFC is to improve the ratio of apparent power and real power. PFC is needed in the power supplies which have more than 75W input power. For example, a 60W PSU with 80% efficiency and a power input of 75W will need a PFC (based on EMC requirements IEC-61000-3-2). However, if the 60W PSU has more than 80% efficiency, about 82% then the Pin is 73W PFC is not needed.
The power factor is only 0.4~0.6 in non-PFC models. In PFC models, the power factor can reach above 0.95.
The calculation formulas are as below:
Apparent Power=Input Voltage x Input Current (VA)
Real Power= Input Voltage x Input Current x Power Factor (W)
The electric power plant needs to generate a power which is higher than apparent power in order to steadily provide electricity to the market. The real usage of electricity should be defined by real power. Assuming the power factor is 0.5, the power plant needs to produce more than 2VA to satisfy 1W real power. On the contrary, if the power factor is 0.95, the power plant only needs to generate more than 1.053VA to provide 1W real power need. It will be more effective to have PFC keeping environment friendly point of view and energy conservation. CliQ DIN Rail Power Supply's 120W, 240W & 480W single phase power supply have this PFC feature. The 60W model needs the PFC feature if the input power exceeds 75W.