Auto-Transformer Starter

Question 1

Operation

Answer 1

An auto-transformer reduces the supply voltage during startup. After the motor reaches a predefined speed, it switches to the full supply voltage.

Question 2

Advantages

Answer 2

Allows greater flexibility in selecting the voltage reduction level (e.g., 50%, 70%).

Provides higher starting torque compared to a star-delta starter.

Question 3

Disadvantages

Answer 3

More complex and expensive than DOL or star-delta starters.

Question 4

Applications

Answer 4

Large motors requiring reduced inrush current but higher starting torque.