The troubleshooting guide outlines a comprehensive variety of motor problems. Generally the categories are arranged according to symptoms offering brief suggestions concerning what to look for when investigating motor failures (why motor fails?) and often providing advice on how to correct the problem once it has been identified.

Motor Shuts Off Before Full Speed
A. Motor also hums (single phase motor)
  • Run winding may have a loose connection - disassemble motor in order to make the appropriate repair
  • C. Excessively low voltage.
    F. Bad capacitor
  • Run winding is burned out - motor must be replaced or rewound

    B. Overloaded
  • Reduce the load.
  • A reasonable overload or voltage drop of 10-15% will reduce speed only 1 to2 percent.
  • A report of any greater drop would be questionable.

    D. Inaccurate method of measuring RPM
  • Check meter using another device or method.

    E. Wrong connections
  • Starts If Shaft Is Spun
    A. This will occur with a split phase or capacitor start motor only.

    B. Check to see if the start winding is burned out.
    • If so, replace the winding or rewind motor completely.
    C. Centrifugal start switch may be bad or contacts dirty
    • Disassemble motor in order to make the appropriate repairs.
    D. Start winding lead may be loose
    • Disassemble motor in order to make the appropriate repair.
    Check the centrifugal starting switch. It may have dirty contacts. If the starting winding is burned out, the motor may start if the shaft is turned. The starting winding should also be checked to see if it is loose or burned out. If the motor has a starting capacitor, check to see that the capacitor is good and replace the capacitor if it is bad. Check the bearings to see if they are locked and will not allow the shaft and rotor to turn.
    Heat is the ultimate threat to a motor's longevity. Excessive heat literally cooks the components of a motor, causing material breakdown, and ultimate failure. It is well known by most motor folks: For every 10 degrees centigrade increase in the operating temperature, there is a corresponding 50% loss in motor life.

    It is important during the selection process, the installation, the ensuing operation and maintenance, to focus on eliminating, or at least reducing, all potential causes of overheating.

    For example, every motor has nameplate information that defines its operating temperature range and its tolerance to temperature rise.

    Adherence to voltage, phase and frequency tolerances insure that the "fuel"for the motor's operation will be as pure as possible.

    Regularly scheduled preventive maintenance that focuses on the motor's physical and electrical environment can help detect potential overheating problems.

    Ultimately, any operation's goal is to produce the most using the least,saving as much as possible. Well thought out strategies that keep motors working longer help to meet the economic goals.
    serviceServo Motor & Drives