Magnetism and electromagnetismQuestion 1245 of 1506

Why are the laminations of an induction motor core coated with oxide or varnish?

To lower the slip
To cut eddy current losses
To raise the supply frequency
To make the cage conduct better

Show answer

Correct answer: To cut eddy current losses

The thin insulated layers stop large eddy currents in the iron.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 13.7: Tesla Polyphase Induction Motors

Questions last reviewed: 18 October 2026

Red Seal Electrician Practice needs JavaScript to run. Use its questions for practice. The real pass mark is usually 70%. Check it with your province or territory's apprenticeship office.