TESTING OF THREE PHASE INDUCTION MOTOR

TESTS WHEN ISOLATED

1) VISUAL TESTS:

• Check that motor frame is mechanically sound. 
• Remove terminal cover plate and check for ingress of foreign material, moisture etc. 
• Check for signs of overheating, arcing or burning. 
• Check ventilation is clear. 

2) ELECTRICAL TESTS:

• Identify windings using a continuity tester. 
• Measure the resistance of the windings ( 3 identical readings ). 
• Measure the insulation resistance between each winding and between windings and frame. 

3) MECHANICAL TESTS:

• Check that the rotor is free to rotate and does so smoothly / quietly.
• Check that motor interior is free of dirt, dust, water and oil.
• Check for play in bearings.

4) TESTS WHEN RUNNING:

• Check run currents ( If uneven check voltage at motor terminals ). 
• Check speed of motor at no load and full load. 
• Check vibration levels and noise levels. 
• Check for temperature hot spots.