Red Seal Electrician Practice
Motor controlsQuestion 71 of 1506

A cooling water system has a flow switch that must close a circuit to sound an alarm when flow is lost. Which contact type is needed?

  1. Normally open
  2. Normally open, timed closed
  3. Make-before-break
  4. Normally closed
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Correct answer: Normally closed

Flow holds a normally closed contact open. When flow stops, the contact returns to its closed normal state.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 4.3: Contact “Normal” State and Make/Break Sequence

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Questions last reviewed: 18 October 2026