Automatic Star-Delta Starter
Q. Automatic Star-Delta Starter.
- Automatic Star Delta Starter is used to save energy during variable load conditions in three-phase induction motor.
- This is done by using a micro controller.
- The three-phase winding inside the motor can be connected in star or delta. About 25-30 % of energy gets saved by incorporating delta star conversion module.
- The starting current of any heavy electric motor can be 10 times more than the normal load current it draws, when it gains speed and has reached its normal running output and temperature.
- So we would require large circuit breakers, which can withstand the starting current to pass without immediately shutting it off.
- If the windings of a 3-phase motor are connected in star the voltage applied to each winding is reduced to only (11√3) of the voltage applied to the winding when it is connected directly across two incoming power service line phases in DELTA.
- The current per winding is reduced to normal running current taken when it is connected in DELTA.
- This can save 25 % of power when compared to delta mode .
- This arrangement leads to better power factor, size of conductor can be reduced and minimizing the starting current will reduce the stress in other equipment.