phase sequence of AC three phase induction motor.
There two types of diagram for Automatic star-delta starter. 1. Control circuit diagram 2. Power circuit diagram We use star -delta starter above 5 HP Motor to reduce the starting current .At first when it started Star contactor and main contactor are on and motor run in star connection. After sometime (8-10sec) motor runs at normal speed then on delay timer change its own contact after that star contactor put off and delta contactor energise and motor runs at full speed in delta mode.