AC Motor Troubleshooting: Resistance, Amps, and Megger Tests Explained

Determining if your AC 3-phase (or single-phase) motor is good or bad doesn't always require an advanced insulation test (megger). In this video, we walk through the essential basic tests—amperage and resistance—that you can perform first to quickly diagnose motor health.

We compare a known good motor with a bad motor using different meters (Fluke 381, T6-1000, and 1587 FC) to demonstrate:

Amperage (Amp) Check: How an imbalance in amp draw across the phases indicates a winding issue.

Resistance (Ohm) Check: Using resistance measurements to confirm winding balance and identify shorts before applying high voltage.

Insulation Resistance (Megger) Test: The proper procedure for performing a megger test to ground and simulating common motor faults to show what bad insulation looks like.

Learn how to interpret your readings and establish a baseline for your motors before they fail!

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Items used in this video:
PLC Trainer https://controls.tw/yt-plc-trainers
Fluke 1587 FC https://controls.tw/fluke-1587-fc
Fluke T6-1000 https://controls.tw/fluke-t6-1000
Fluke 381 https://controls.tw/fluke-381

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