EE 216 Electrical Engineering Dr Unnikrishnan P C

EE 216 Electrical Engineering Dr. Unnikrishnan P. C. Professor, EEE

Module II

Single-Phase Motors Split-Phase Motors • Split-phase motor classifications: – the resistance-start induction-run motor – the capacitor-start capacitor-run motor • Split-phase motors use two separate windings to create the necessary rotating magnetic field. These windings are named the start winding and the run winding.

Auxiliary Windings Two windings that are 90° apart physically and carrying currents 90° apart in phase produce a rotating magnetic field. Single-phase induction motors contain an auxiliary winding displaced by 90 electrical degrees from the main winding.

Single-Phase Motors The start winding is made from small-gauge wire. The run winding is made from largergauge wire.

Ceiling Fan- Single Phase IM

Ceiling Fan- Stator and Rotor

Single-Phase Motors A centrifugal switch disconnects the start winding when the motor attains 75% of the rated speed.

Single-Phase Motors To calculate the speed of a rotating magnetic field: Speed = (120 x frequency) / poles.

Basic Single-Phase Induction Motor The pulsating flux produced by the main winding can be resolved into two counterrotating components.

Flux components in the stator of an IM

The Split-Phase Induction Motor

The Capacitor Start Capacitor Run IM