Star-Delta Starter

Question 1

Operation

Answer 1

Initially connects the motor windings in a star configuration, reducing the voltage across each phase to 1/√3 of the line voltage

Once the motor reaches a certain speed, it switches to a delta configuration for full voltage operation.

Question 2

Advantages

Answer 2

Reduces starting current to approximately 33% of the DOL current.

Limits mechanical stress during startup.

Question 3

Disadvantages

Answer 3

Lower starting torque in star mode

Question 4

Applications

Answer 4

Medium sized motors where reduced starting current is needed