Motors can fail or appear to be faulty as a result of system related mechanical and/or electrical problems. Many motors are replaced unnecessarily because they are incorrectly judged to have failed. Before condemning the motor, be sure that none of the system-related mechanical or electrical conditions listed below are causing the problem.
• Check for low supply voltage.
• Check for a motor contactor not making good contact on all poles.
• Check for an open or weak run capacitor.
• Check for tight bearings due to lack of lubrication. If applicable, lubricate the bearings per the manufacturer’s instructions. Note that motors with “ lifetime” lubricated bronze bearings typically have a life of 5 to 7 years. After this, the bearings tend to become tight because they run out of oil.
• Check for tight belt tension or misaligned drive pulleys.
• Check for correct fan blade location, or for bent shroud or housing.