Online power factor improvement of induction motors

A description is given of the design and implementation of a simple scheme to achieve online and dynamic power-factor improvement of single and three-phase induction motors subjected to variable loads. The proposed scheme uses a fixed-capacitor thyristor-controlled-reactor type of static compensator along with associated control circuits. The results show that under all loading conditions, a power factor of almost unity is achieved automatically. The waveform of supply current can be kept almost sinusoidal. The response time of the scheme to motor load changes is quite reasonable. Details regarding design, implementation, analysis and operation of such dynamic power-factor compensators are provides.<>