Permanent Split Capacitor (Capacitor Run) AC Induction Motor

A permanent split capacitor (PSC) motor has a run type capacitor. This capacitor is permanently connected in series with the start winding. This will cause the start winding an auxiliary winding once the motor reached the running speed. It cannot provide the starting boost of a starting capacitor since the run capacitor must be designed for continuous use. PSC motor has low typical starting torque , from 30% to 150% of the rated torque. What’s makes PSC motors excellent for applications with high on/off cycle rates is because it’s have low starting current, usually less than 200% of the rated current.

Below is several advantages of PSC motors: The motor design can easily be altered for use with speed controllers. PSC motors can also be designed for optimum efficiency and High-Power Factor (PF) at the rated load. Because no centrifugal starting switch is required, they’re considered to be the most reliable of the single-phase motors.

Depending on the design, permanent split-capacitor motors have a wide variety of applications. These include fans, blower with low starting torque needs and intermittent cycling uses, such as adjusting mechanism, garage door openers and gate operator. [Circuit diagram source: Microchip Application Note]