Red Seal Electrician Practice
MotorsQuestion 905 of 1506

In a DC motor, what do the brushes make possible?

  1. They store energy to help the motor start.
  2. They change AC supply into a magnetic field.
  3. They keep the magnet from spinning.
  4. They reverse the coil current every half turn.
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Correct answer: They reverse the coil current every half turn.

The brushes and the strips on the shaft switch the coil connections each 180 degrees so that the torque stays in one direction.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 1.1: What is Alternating Current (AC)?

Practice motors

Questions last reviewed: 18 October 2026