Motor Testing

Motor Testing



Checking motor winding resistance for identification of winding terminals with a VOM or Amprobe
Run Winding Resistance
Lowest
Start Winding Resistance

Between Lowest and highest (3 to 5 times run resistance)
Run to Start Resistance
Highest

Example

Common to Run Terminal =

3 ohms (lowest)
Common to Start Terminal =

10 ohms
Start to Run Terminal =
13 ohms (highest)

 




Example #1 Identify Motor Terminals
Terminal A to Terminal B
12 ohms
Terminal A to Terminal C

9 ohms
Terminal B to Terminal C

3 ohms


Example #2


Terminal A to Terminal B
6 ohms
Terminal A to Terminal C

2 ohms
Terminal B to Terminal C

8 ohms





Return to Basic Electrical Motor Theory

 




















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