We have a problem in my plant with VFDs using an ice cube type relay for the start circuit. These relays are 120vac coils with a PLC output energizing them. Quite ofter when the output is off the relay will remain energized. I am assuming that the leakage voltage from the transistor output of the PLC is just enough to hold the relay. If the relay is pulled and put back it will not energize until the PLC output is high again. I am hoping that adding a bleeder resistor accross the relay coil will cure the problem.
I am interested in hearing if others have had this problem and what your cure was.
Thanks in advance,