AC Torque Motor Control with PLC

[Tenbaum]

HI guys new to this site, I just starting working with plcs and have a question. I have two AC Torque motors (advantage is these ac motors provide a constant torque at stall without burning out the motor). I need to control the torque automatically with a plc (the work with tension sensors to provide the proper amount of torque to keep constant tension in the spooling fiber). In order to control the motors you need to vary only the voltage supply; i.e. variable frequency drives will not work. Someone mentioned an analogue triac output but I have not seen any sort of variable voltage ddrive that can connect to a plc. Does anyone have any solutions. I have to use these AC torque motors, I think servo motors are way beyond my budget. Thanks.

Alex

 

[rdrast]

Single phase or 3 phase? eh, doesn't matter. If you just need to control the motor's terminal voltage, consider using something like a heater power controller.

http://www.watlow.com/products/controllers/power/dinamite.cfm

Something like that. They have bang-bang models, and models that have variable output, either 4-20 or 0-10v controls.

 

[cntrlfrk]

I'm not sure why you can't attain torque control with a freq. drive. I have used drives to control output voltage instead of frequency (we actually used it to control voltage to a large electric element heat exchanger) . I can't find any info on the type I have used, but it appears the A-B 1336 PLUS II has selectable freq/voltage control.

http://www.ab.com/drives/1336PlusII/index.html

 

[rdrast]

I'm not sure why you can't attain torque control with a freq. drive. I have used drives to control output voltage instead of frequency (we actually used it to control voltage to a large electric element heat exchanger) . I can't find any info on the type I have used, but it appears the A-B 1336 PLUS II has selectable freq/voltage control.

http://www.ab.com/drives/1336PlusII/index.html

Because he is using an actual torque motor, not a standard induction motor. A vector drive, either with an encoder on the motor or sensorless mode works as a torque source with a regular motor. A torque motor is a different beast.

 

[TConnolly]

http://www.ccipower.com/products/

 

[Tenbaum]

Hey thanks for all the help, but any more information you guys have would be great. You all are obviously a knowledgeable bunch. Yeah it is actually a special ac motor (here is the link from oriental motor http://catalog.orientalmotor.com/vi...motors?&plpver=11&forward=1&backtoname=&pane=) it is able to supply constant torque in stall. But I really need to just control the voltage, one reason being the variable frequency drives maybe excessive for what we're are trying to achieve and they may not work for our purpose. I'm am working on the Nova neutrino detector and we need to keep things within range of our monetary limit. Thanks again.

Alex

 

[theDave2]

Tenbaum: Why not ask Oriental what they recommend?

And then dope slap the person that bought them in the first place without knowing how to control them & consulting you.

the work with tension sensors to provide the proper amount of torque to keep constant tension in the spooling fiber

I doubt very much that this type of motor is what you want. Please describe in much detail what you are doing.

 

[Tenbaum]

Okay

There are two fiber spools each with a mounted ac torque motor. The spooling fiber is being spooling onto a spooling fiber for a particular length. The fiber is then de-spooled from both spools and cut in as its being pulled from both spools. The machine is only in motion about a third of the time but a certain amount of tension needs to be applied even in this stall mode in order to prevent tangles (its a wavelength shifting fiber and is very expensive). Hence the reason for ac torque motors to supply torque to create this tension. That same level of tension needs to be regulated while the machine is in motion (via tension sensor inputs to the plc) Essential the program logic will ideally take tension level inputs and send a vary ac output voltage to the motors (PID) for continuous tension control. thanks again.

tenbaum