Which statement correctly distinguishes capacitor-start induction-run motors from capacitor-run motors?

Which statement correctly distinguishes capacitor-start induction-run motors from capacitor-run motors?

• A. Capacitor-start motors use a centrifugal switch to disconnect the start winding and capacitor, while capacitor-run motors do not.
• B. Capacitor-run motors use a centrifugal switch to disconnect the run capacitor.
• C. Capacitor-start motors have no windings.
• D. Capacitor-run motors cannot have starting torque.

Answer: (A)

The main idea is how the starting circuit is managed after the motor begins turning. In capacitor-start induction-run motors, a centrifugal switch senses speed and disconnects the start winding and the starting capacitor once the rotor reaches a set speed. This gives a large starting torque, then the motor runs with only the main winding (and the run capacitor, if present) in the circuit. In capacitor-run motors, there is no centrifugal switch to drop out the starting components; the run capacitor stays connected during running to improve running torque and power factor, so starting torque is typically lower than a capacitor-start design. The other statements aren’t accurate because there are windings in capacitor-start motors, capacitors aren’t typically disconnected by a centrifugal switch in capacitor-run designs, and capacitor-run motors can have starting torque, just not as high as capacitor-start motors.

The main idea is how the starting circuit is managed after the motor begins turning. In capacitor-start induction-run motors, a centrifugal switch senses speed and disconnects the start winding and the starting capacitor once the rotor reaches a set speed. This gives a large starting torque, then the motor runs with only the main winding (and the run capacitor, if present) in the circuit. In capacitor-run motors, there is no centrifugal switch to drop out the starting components; the run capacitor stays connected during running to improve running torque and power factor, so starting torque is typically lower than a capacitor-start design. The other statements aren’t accurate because there are windings in capacitor-start motors, capacitors aren’t typically disconnected by a centrifugal switch in capacitor-run designs, and capacitor-run motors can have starting torque, just not as high as capacitor-start motors.