Why we need star delta starter ?
- Initial current can be 4 times higher than the normal load current . 2.Very heavy torque on motor 3.Large contactor and cable size required to run directly in delta mode.
Solution - Initially run motor in star mode and then in delta mode
Star mode -
Contactor Q1 and Q2 will be on and Q3 will be off.
Contactor Q1 and Q3 will be on and Q2 will be off
Control circuit for Start to Delta Starter