Red Seal Electrician Practice
Motor controlsQuestion 15 of 1506

Why is the stop button in a start-stop circuit a normally closed contact?

  1. It stays open until it is pressed, then it connects the coil to the supply
  2. It passes power to the coil when released and opens the circuit when pressed
  3. It carries the full motor current for the whole time that the motor runs
  4. It is the contact that seals in the starter when the start button is released
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Correct answer: It passes power to the coil when released and opens the circuit when pressed

A normally closed stop switch conducts when released, and pressing it unlatches the contactor.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 6.4: Motor Control Circuits

Practice motor controls

Questions last reviewed: 18 October 2026