Red Seal Electrician Practice
Motor controlsQuestion 22 of 1506

A solenoid valve controls cooling water to a machine. A running machine without coolant would be badly damaged. Which valve is the better fail-safe choice?

  1. A valve that opens only when the solenoid is energized
  2. A valve that opens when the solenoid is de-energized
  3. A valve with a latch that holds its last position
  4. A valve that closes when the solenoid is de-energized
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Correct answer: A valve that opens when the solenoid is de-energized

An open coil or broken wire is most likely, so the valve should pass water with the coil off.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 6.5: Fail-safe Design

Practice motor controls

Questions last reviewed: 18 October 2026