RICHARD HALE, MANAGING DIRECTOR OF THE DERITEND GROUP, OFFERS SOME POINTERS ON WHY MOTORS FAIL, AND WHAT TO DO ABOUT IT WHEN THEY DO. Electric motors fail for a number of reasons wholly unrelated to their age and to the hours that they have been operating, Problems with power supplies, overheating, contamination, insufficient or unsuitable lubrication and unusual loads can all play their part in impairing the efficient operation of motors, leading to premature - and usually costly - failure for the motor user, Addressing these factors is crucial, therefore, for any enterprise that is seeking to extend motor life, reduce downtime and improve OEE. In any study of the factors that cause motors to fail, the logical place to start is the power supply, With a properly conditioned and regulated power supply, the output to the motor should be a perfect sine wave on each phase at the motor's ranted voltage and frequency However, this is rarely achieved, and the result can be a host of problems including: harmonics, which cause overheating and reduced efficiency; overvoltage and undervoltage, the former reducing efficiency and power factor while the latter increases current and causes overheating; and voltage imbalances, which cause overheating and reduce efficiency.
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