Three phase induction motors can be started:
1. Direct Online- direct-on-line: which means that the rated supply is directly applied to the motor.
2. Starting Of Squirrel Cage Motors: Starting in-rush current in squirrel cage motors is controlled by applying reduced voltage to the stator.
3. Auto- Transformers: It is basically a three phase step down transformer with different taps provided that permit the user to start the motor at, say, 50%, 65% or 80% of line voltage.
4. Star-Delta Starter: This method is used in the motors, which are designed to run on delta connected stator.
5. Starting Of Slip-Ring Motors: Slip-ring motors are started with full line voltage, as external resistance can be easily added in the rotor circuit with the help of slip-rings.
