Star Delta Contactor

Trane CTR0344E Contactor Tripol 150AMP. Star / Delta Contactor.

Most induction motors are started directly on line, but when very large motors are started that way, they cause a disturbance of voltage on the supply lines due to large starting current surges. To limit the starting current surge, large induction motors are started at reduced voltage and then have full supply voltage reconnected when they run up to near rotated speed.