Wiring of Local Control Station for Motor

[timm333]

I am trying to figure out the wiring of local control station for direct-on-line (DOL) low voltage motor. The motor is controlled by magnetic starter and digital overload relay in MCC, and local control station in the field.

The local control station has switches (“start”, “stop”, and “hand-off-auto”) which are sometimes wired in series and sometimes in parallel. If we have to communicate three signals (“Start”, “Stop”, “Auto Status”) from local control station to MCC and then from MCC to Remote-PLC: then should the three switches of local control station ((“start”, “stop”, “hand-off-auto”) be wired in parallel or in series? Thanks

 

[LarryFine]

I would search for images of motor control wiring until I find the right circuit/diagram.

 

[don_resqcapt19]

Typically the hot for the motor control circuit supplies the HOA switch. In the hand position, that in turn supplies the start stop buttons wired as a standard 3 wire control circuit. In the auto position, the HOA supplies whatever automated control device that controls the motor.

The communication of auto status is typically by an addition contact on the HOA that provides feedback to the control system telling the system that the switch is in the auto position. This is often a second circuit from the motor control circuit.

 

[petersonra]

I am trying to figure out the wiring of local control station for direct-on-line (DOL) low voltage motor. The motor is controlled by magnetic starter and digital overload relay in MCC, and local control station in the field.

The local control station has switches (“start”, “stop”, and “hand-off-auto”) which are sometimes wired in series and sometimes in parallel. If we have to communicate three signals (“Start”, “Stop”, “Auto Status”) from local control station to MCC and then from MCC to Remote-PLC: then should the three switches of local control station ((“start”, “stop”, “hand-off-auto”) be wired in parallel or in series? Thanks

I am not sure what you are asking but if you are running them all back to the plc none are wired in series or parallel.

 

[ptonsparky]

An interposing relay controlled by the PLC is in series with the Auto position. At least that’s the way I did my very Basic setups. All interlocking etc was done in the program logic. All my stuff was pretty simple.