Star Delta Starter Sizing & Selection
Star delta starter generally find application in Industrial & Commercial loads . Star delta starter reduces starting current by (3 to 5) times than that DOL starter. It is important to know ratings of starter components for different HP motors . Improper selection & Sizing of components in starter may lead to damage to motor windings , or motor may be in standstill . Operation of star Delta starter : At starting / standstill condition motor draws high current ,to reduce the high starting current drawn by motor, motor is connected in star mode ,where phase voltage is applied across motor causes motor to draw only low starting current untill it reaches (75 to 80 %) of rated speed. After attaining rated speed motor gets connected in delta connection with full line voltage gets applied on motor winding . Motor continous to run in delta connection because Torque obtained in delta connection is more than in star connection . Note:- Generally in all industries & Manufacturi