On several occassions it was noticed by operators that a 1750 HP compressor motor shot "sparks" or "fire" out the back when it started. The motor is open frame. After starting the motor would continue to run, at times for over a week before being shut down based on system...
We experienced the simultaneous failures of two 4kV fan motors on a high resistance grounded system. They were on the same switchgear bus, a 6000 HP fan (located outside) and a 600 HP fan (inside) – both less than 300 feet from the bus. The 6000 HP fan has surge protection at its terminals –...
Molded case breakers in motor control centers are often operated indirectly by an external handle on the front of the MCC cubicle. As the mechanical linkages wear over time and the original circuit breakers are replaced with breakers that are not dimensionally identical, how do you ensure...
