Shared transducer

[ptonsparky]

I have several motors <=15HP that never run at the same time but I would like to get feedback when each does. The output goes to a plc. Not high accuracy requirement but it does initiate a shut down when parameters are exceeded. I would monitor one phase of each motor after its starter. Is there a reason I should not do this?

 

[don_resqcapt19]

Why not monitor the auxiliary contact in the starter? Or if you need proof of motor operation, a CT switch in one of the t leads.

 

[ptonsparky]

Why not monitor the auxiliary contact in the starter? Or if you need proof of motor operation, a CT switch in one of the t leads.

I use the current to monitor a load(s) that can vary to the point of plugging an auger or conveyor. Plugging may result in burnt conveyor belts. I monitor RPM on some now, but not all. I’m no longer the EC. Just a programmer. More parts wait on the EC and he’s busier than I ever thought or wanted to be.

It’s a struggle to get an area millwright to put the weakest link at the start. Not midway or the end. This makes 5 years of equipment changes and may be the closest to fully automatic operation.

Eta. All motor starters are monitored via an aux contact.

 

[Jraef]

Is there a common feed to the motor controllers? If so, one current transducer on that feed, combined with logic from the aux contact if each starter do you know which one you are looking at.

 

[ptonsparky]

Is there a common feed to the motor controllers? If so, one current transducer on that feed, combined with logic from the aux contact if each starter do you know which one you are looking at.

Unfortunately, not a common feed for just the motors I want, but the taps at the terminal block is the next best.

 

[don_resqcapt19]

Run one T lead from each motor through a single current transmitter, (or switch if you just need a digital, not analog signal) if all of the T leads are available at a common point.