A Motor to Meet All Your Electronic Cooling Applications: PSC Motors

Author: Yake Dong

The PSC or permanent split capacity motor is a compact and high-power motor that is widely used in 2 horsepower or less machines, as well as for applications where the starting torque requirement is equal to or less than the full load. This motor design is also mostly seen in electronic cooling and air conditioning applications as it offers the advantage of operating at different speeds with higher levels of slip. This unique capability, makes the motor highly beneficial for special applications such as in fans and blowers, coolers, air conditioners, unit heaters, furnaces, roof ventilators, dehumidifiers, and other HVAC uses, as well as other applications like garage door openers and systems or machines that require low current and starting torque.

The PSC's compact design is also one of its major advantages, offering great efficiency and high power within a small and easy to maintain motor. It offers smooth acceleration and features run and start windings, including a capacitor, which connects in series. Both the run and start winding are energized as the motor runs and no switch is needed to take any component out of circuit.

PSC motors are also designed with good starting and running torques, which makes them perfect for electronic cooling applications. Because the capacitor also remains within the circuit even during operation, it corrects the power factor for the motor. Additionally, the stator winding of a PSC motor is different from a typical capacitor-start, induction-run or resistance-start, induction-run motors, placing the run winding lower within the core material, thus helping it increase inductance.

Permanent split capacity motors, much like most types of AC induction motors, offer peak efficiencies at a speed point that is 5 to 10 percent below synchronous speed. This synchronous speed is determined by the speed of the rotor from the stator windings. PSC motors are generally designed with multiple speeds and they achieve peak efficiency on the highest speed. When lower speeds are used--for instance when using the machine in constant fan mode--motor efficiency decreases dramatically.

When your cooling system's PSC motor starts to fail, going directly to the machine's manufacturer to get an identical replacement is the simplest solution, especially when you want to make sure that the unit will work as intended and meet the system configuration perfectly. However, it is not hard to find units that are electrically and mechanically identical to what you need, if you know where to look.

About the Author:

This article is written by Jack Wang who is associated with GEMS Motor. Jack got his Bachelor's degree in Mechanical Engineering and Master's degree in Electrical Engineering, specialized in electric motor design and motor driver development. Jack was born in greater Shanghai area, China, and had several years of study and work experience in the United States. With the deep knowledge of electric motors and great bilingual skills in Mandarin and English, Jack helps market our electric motor products worldwide. Jack currently holds the position of Director of Marketing at GEMS Motor.