We have recently tested numberous Square D Mastpact NW & NT circuit breakers and are having a 50+% failure rate, when performing primary current injection tests. All other tests are OK (insulation resistance, contact resistance, Trip Unit pick-up). We are finding that the breakers, in...
Can anyone point me to an IEEE or ANSI standard that addresses the maximum variation in transformer impedance for a three-phase delta connected bank? I cannot seem to find a definitive answer, but rather some generalities (such as + or - 7.5%).
I have a client who recently lost two...
