Electric Motor Repairer how-to

How to Test a Motor’s Insulation with a Megger

Insulation tests catch failures early.

Updated By the Career Education Institute Curriculum Team
Quick answer

Insulation tests catch failures early. In short: lock; disconnect; connect, then complete the remaining steps below.

Step by step

  1. Lock out the motor.

  2. Disconnect leads.

  3. Connect the megger.

  4. Apply test voltage.

  5. Read resistance.

  6. Compare to standards.

Safety reminders for electric motor repairers

  • Lock out power
  • Use lifting equipment
  • Ventilate varnish areas
  • Wear eye protection

Stator · Rotor · Armature · Winding · Megger · Surge test: see the full electric motor repairer glossary.

More electric motor repairer how-to guides

Learn this in Electric Motor Repairer trainingTake the practice test
Enroll in trainingTake fit quiz