overload relays
overload relays
(OP)
i have recently came across a situation that a contractor was removing the wiring from the N/C contacts on a overload relay to the motor starter. He was then rewiring the contacts on the overload relay to provide a PLC an input, which then was used to shutdown the output. I am concerned with the use of a PLC to provide the shutdown of the motor in the case of an overload. Does anyone have any opions on this?





RE: overload relays
RE: overload relays
If your system needs to monitor operation of the overload and there is no second contact available, then wire a PLC input from the hot wire to the coil side of the overload contact. The input will be normally energized, de-energized only when the overload N/C contact opens or the starter supply is lost.
RE: overload relays