How does an induction motor start?(Starting an induction motor).
An three phases induction motor may start by itself. A revolving magnetic field is produced when the supply is connected to the stator of a three-phase induction motor, which causes the rotor to start rotating and the induction motor to turn on. The motor slip is equal to one and the starting current is very large at this time.
DOL: direct online starter
An induction motor can be started directly online in a simple and affordable manner. The starter is connected directly to supply voltage using this technique. Small motors up to a 5 kW rating are started using this technique to prevent supply voltage fluctuations.
Star delta starter
The most popular and extensively used method for starting three-phase induction motors is the star delta starter method. During starting the motor operates using star connection after few second the delta-connection applied to the stator windings in this technique.
Auto transformer starter
In either a star-connected or a delta-connected connection, the autotransformer is used. The induction motor's starting current is adjusted by the autotransformer.
The squirrel cage rotor induction motor uses the three starters mentioned above.
There are some other options to start the motor:
- Resistance starter
- Series reactor starter
