Lucky_Bugger
Member
Hi,
I'm a bit new to all this, however...
I'm trying to control a DOL motor using a PLC output.
At the moment i have a PLC output directly driving a contactor supplying power to the motor. The rating of the PLC output is high enough to drive the contactor coils.
On other circuits ive seen, people sometimes use an intermediate relay on the plc output to drive the contactor coil. This relay would be supplied from the PLC output in series with the auxilliary contacts on the motor overload, breaker and isolator. I.e. its hard wired.
What i'm intending to do is to feedback the overload auxilliary, the isolator auxilliary and the breaker auxilliary to the PLC and get the program to decide when to drop out the contactor.
The question is, is this the wrong way of doing it?
Ive attached a PDF of the circuit.
I should have added, if it is the wrong way of doing it, why is it?
I'm a bit new to all this, however...
I'm trying to control a DOL motor using a PLC output.
At the moment i have a PLC output directly driving a contactor supplying power to the motor. The rating of the PLC output is high enough to drive the contactor coils.
On other circuits ive seen, people sometimes use an intermediate relay on the plc output to drive the contactor coil. This relay would be supplied from the PLC output in series with the auxilliary contacts on the motor overload, breaker and isolator. I.e. its hard wired.
What i'm intending to do is to feedback the overload auxilliary, the isolator auxilliary and the breaker auxilliary to the PLC and get the program to decide when to drop out the contactor.
The question is, is this the wrong way of doing it?
Ive attached a PDF of the circuit.
I should have added, if it is the wrong way of doing it, why is it?
Last edited: