Meters and troubleshootingQuestion 185 of 1506

The coil of a contactor measures 0 Ω with the power off. What does this show?

  1. The coil is in good condition
  2. The coil winding is open
  3. The contacts are stuck closed
  4. The coil is shorted and bad
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Correct answer: The coil is shorted and bad

A good coil has some resistance. A reading of zero means a short, and a reading of infinity means an open. Both are faults.

Source: Troubleshooting Motors and Controls (Dickson-Self), 1.2: Electrical Fundamentals

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Questions last reviewed: 18 October 2026