How do you test an AC motor?

The AC/DC Motor Test Bench under HV Hipot Electric Co., Ltd. can help many power workers conduct various power tests more conveniently.

How to Test an AC Motor (Text-Only):

1.Power-Off Checks (Safety First):
Disconnect power and verify zero voltage
Manually rotate rotor: Check for jamming or bearing noise
Inspect visually: Look for burns or corroded terminals

2.Insulation Test (Megohmmeter):

Winding-to-ground: >1MΩ (for 380V motor)
Phase-to-phase: >1MΩ between any two windings
>0.5MΩ in humid environments

3.Winding Test (Multimeter):

3-phase balance: Resistance difference <2% across windings
Single-phase: Main/auxiliary winding resistance should match specs

4.No-Load Test (Powered):

Start at rated voltage
Measure phase currents: No-load current ≈ 20%-50% of rated current
Listen for noise: Uniform hum (abnormal: screeching/irregular sounds)
Check temperature: After 30 mins, case temperature rise <70℃

5.Load Test (Critical):

Gradually increase to rated load
Monitor:
Phase current balance (deviation <10%)
Speed fluctuation <5%
Bearing temperature <95℃
Abnormal vibration

6.Special Checks:

Capacitor test (single-phase): Capacitance degradation <10% of rating
Rotation direction: Confirm matches requirements