Had a 10yr old 600 volt 10kvar capacitor bank short and shut down both a 2000 ton chiller plant plus a 1400hp boiler plant(critical motors for both are fed from the same MCC).So far Ive found a total of 4 caps open and 1 shorted of the 9 on this MCC.Also I'm finding power factors of .8 to 8.4 once the caps are removed from circuit.I thought that 8.4 was pretty good and checked with an EE Apparently 8.5 is the factory cut off point.These are 30HP to 50HP motors.
What is the life expectancy of the typical power factor capacitor?I've seen many of them in service for 15yrs and never a problem?