The PS&C Service Division
recently surveyed customers to get historical data concerning bearing failures. All customers contacted had PS&C Service Maintenance Contracts
or purchased maintenance at regular intervals. The results may amaze you.
In 22 years
of operation of over 350 systems
, only two bearing replacements were recorded. One at the Patent and Trade Office in Washington D.C.
, a site with four 1000kVA
systems. A pony motor bearing was replaced after a noise was detected during operation and the second was at Cincinnati Bell
as a generator bearing was noticed to be running warmer than normal during the start-up and was replaced before the unit was put on-line.
When analyzed this really is not surprising. PS&C's motor generators actually consist of two synchronous generators, the identical type of synchronous generator that is supplied with every gen-set sold in the world. They just use one machine as a motor. PS&C also adds one additional bearing to each machine; this spreads the weight out over four bearings. PS&C runs the power conditioning M-G sets continuously which causes less stress on the overall bearings that the start/stop type of operation of a typical gen-set.