When testing rotation to ensure it hasn't changed, what does confirming tester operation help verify?

When testing rotation to ensure it hasn't changed, what does confirming tester operation help verify?

• A. To confirm ground continuity
• B. To confirm voltage magnitude
• C. To confirm proper phase sequence
• D. To confirm insulation resistance

Answer: (C)

Phase sequence determines the direction a three-phase motor will turn. When you test rotation, you’re checking that the order of the three voltages—the phase sequence—hasn’t changed, so the motor would spin the same way as before. But you can only trust that result if the tester is working correctly. Verifying the tester’s operation ensures its reading about the phase order is accurate, letting you conclude that the rotation direction remains the same. Ground continuity, voltage magnitude, and insulation resistance relate to safety and electrical health, not the rotational direction.

Phase sequence determines the direction a three-phase motor will turn. When you test rotation, you’re checking that the order of the three voltages—the phase sequence—hasn’t changed, so the motor would spin the same way as before. But you can only trust that result if the tester is working correctly. Verifying the tester’s operation ensures its reading about the phase order is accurate, letting you conclude that the rotation direction remains the same. Ground continuity, voltage magnitude, and insulation resistance relate to safety and electrical health, not the rotational direction.