We offer a selection of motor run capacitors to improve single-phase AC motor running characteristics while not drawing excessive current
What is a motor run capacitor?
A motor capacitor, such as a start capacitor or run capacitor (including a dual run capacitor) is an electrical capacitor that alters the current to one or more windings of a single-phase alternating-current induction motor to create a rotating magnetic field.
There are two common types of motor capacitors: motor run capacitors and motor start capacitors.
Motor run capacitors: Some single-phase AC electric motors require a "run capacitor" to energise the second-phase winding (auxiliary coil) to create a rotating magnetic field while the motor is running.
Run capacitors are designed for continuous duty while the motor is powered, which is why electrolytic capacitors are avoided, and low-loss polymer capacitors are used. Run capacitors are mostly polypropylene film capacitors.
What does a motor run capacitor do?
A variation of the capacitor-start motor is to start the motor with a relatively large start capacitor for high starting torque, but leave a smaller value motor run capacitor in place after starting to improve running characteristics while not drawing excessive current. The additional complexity of the capacitor-run motor is justified for larger size motors.
