Induction Motor On/Off control using PLC

[Dhillis]

I have an Induction Motor (415V, 3 Phase, 0.37Kw, 1440 rpm, 1.4Amps, PF: 0.670, Connection: STAR, Harmonic make) which is used to run a Belt Conveyor. Is there any problem if i implement simple On/Off control to start and stop the conveyor at regular intervals. The conveyor should be made On and Off according to the feedback from a photoelectric sensor. According to the machine design they haven't used any VFD. Please give me an answer..Thanks in Advance.

 

[balash]

In a star connection and so small power i'd say no. Just use a contactor that would be controlled with aux mini relay or you can use low consumption contactors like schneider BL series.

 

[leitmotif]

A simple PLC controlled relay to start and stop motor would be simplest and least expensive.

The only concern would be motor heating from frequent starts n stops. Every 10 second be careful, 10 minute no problem.

Dan Bentler

 

[Adam303]

I'd use a pneumatic clutch for this type of operation.

 

[Dhillis]

I am definitely using a contactor..But what is a pneumatic clutch..and what advantages can i get if i use a VFD in the design..and how?

 

[soolocks]

A pneumatic clutch uses air to engage and disengage motor from whatever it is moving, such as a belt or something.
For your application, that would work or something like an electric clutch such as on an automotive A/C compressor.
The motor should run all the time. Starting and stopping it rapidly will not work well.

 

[Lancie1]

Before we all get too far down the "It Won't Work" road, we need to find out the start/stop rate. How many starts per minute or per hour? That will determine whether it will work successfully or will burn out the starter contacts.