Possible Cause: Motor is overloaded.
Corrective Action: Verify system balance.
Possible Cause: Improper voltage.
Corrective Action: Verify voltage to motor matches the nameplate requirement.
Possible Cause: Unbalanced voltage/single phasing a three phase motor.
Corrective Action: Verify all legs are providing proper voltage.
Possible Cause: Improper motor wiring.
Corrective Action: Verify motor wiring matches motor wiring diagram.
Possible Cause: Damaged shaft or bearings.
Corrective Action: Examine shaft and bearings for damage. Replace blower assembly if necessary.