To control motor through PLC

the_msp said:

OK. You need to replace this with a VFD that can accept an analog current input signal.

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Given the motor, what he really needs is a clutch control that accepts an analog input. Just popping on a VFD won't control the clutch.

The important question is the application. Is this really being used for speed control, or is its main purpose in torque limiting, and speed control is a side benefit?

Good point, I only spent seconds looking at the links.


For my own learning benefit, is this a relatively old concept way of doing things (what the OP has existing now). With the modern equivalent being servo giving speed and torque control?

The old tubing mills I used to work on (circa 1940's) were a set of DC motors on a single drive. Each motor had a large rheoatat on the field winding to individually set the motor speed. The slip clutch things we're usually more for torque control, like rewinders.

Today, you can do the same thing with a vfd, since you can also limit the current. But the OP would also need to change the motor to one without the clutch.

Thanks for the info - I'm a millennial, used to replacing stuff older than me, lol.

the_msp said:

Thanks for the info - I'm a millennial, used to replacing stuff older than me, lol.

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I'm one of the younger baby boomers and started out doing the same thing. Along the way the old stuff has worked its way up to installed after I was born then on to installed since I started my career or even worked on myself.

Sometimes the old stuff lives on. In the basement of a college lab building I could trace the evolution of the GE Controls logo from 1930s serif font through 1950s script and 1980s 300 Line. A Square D enclosed contactor recent enough to have a vinyl label instead of metal had a recycled Start-Stop station on the side, probably Cutler-Hammer, with nameplates dated 1936, 1937 and 1938.

The only eddy current clutches I've seen in operation were on an old central sewage pump station in 1989. We were starting up the new pump station that would replace it.


Mike

Motorized Potentiometer

Mike Lamond said:

...

Sometimes the old stuff lives on. In the basement of a college lab building I could trace the evolution of the GE Controls logo from 1930s serif font through 1950s script and 1980s 300 Line. ...

Click to expand...

In the next iteration, they are going to change to big block capital letters and change the spelling of GE to “ABB”...