In this topic, you study Capacitor Run Motor – Theory, Construction, Diagram, Working & Torque Speed Characteristic.
Capacitor Run motors are commonly called as fan motors. In Capacitor Run Motor, the auxiliary winding (A) along with the capacitor (C) is in the circuit for both, starting and running (Fig. 1).
Fig. 1: Schematic representation of a permanent-split, capacitor type, single-phase induction motor.
Torque-Speed Characteristic of Capacitor Run Induction Motor
Since the capacitor and auxiliary winding remains permanently in the circuit, this improves the power factor and running performance of the motor. However, the starting torque of this type of motor is not good (it is only 50 to 100 % of the full-load torque) as the value of the capacitor has to be chosen as a compromise between best starting and best running conditions. The resulting torque-speed characteristic of this type of motor is shown in Fig. 2.
Fig. 2: Typical torque-speed characteristic.
