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Exercise Circuit Breakers – Most Important and Cheapest Maintenance

September 22nd, 2009 Comments off

Medium Voltage Air Circuit Breaker

Buy Medium Voltage Air Circuit Breakers

We have always said, if you can’t do any maintenance on your circuit breakers, then at least exercise them whenever you have a chance.  All circuit breakers, whether Square D, GE, Westinghouse, anyone’s, are much more reliable if they are exercised.  High voltage or low voltage, they all need to be exercised.  It’s the cheapest, easiest maintenance there is.   It may not be real sophisticated, but it sure works.  We saw this proven again during a plant maintenance shutdown. In this case the medium voltage vacuum circuit breakers had not been touched for 5 years, outdoors, cold winters, no heaters.  Nearly all the lubricated mechanical operating parts were very stiff and many of the circuit breakers just would not operate.   The good news is the breakers would have tripped open, but nobody in their plant was going to get many of them to close again. It was an old fashioned job of cleaning off the hardened lubricant and re-lubricating cautiously.  Too much lubricant is a big problem in many facilities, especially one that does maintenance twice a decade.  And one more note.  Certain large old molded case circuit breakers, especially those used as main breakers, are extremely vulnerable to stiffing up if they are not operated a few times.