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Motor Control/Sensor Question

Motor Control/Sensor Question

Motor Control/Sensor Question

(OP)
At a high level I would like to understand if I can connect a servo motor directly to a cable reel and have the motor interpet cable line "looseness" (torque) as it winds/unwinds...adjusting speed accordingly per a PLC/software program.  I can provide more information (load magnitude, etc...)once deemed possible.

Thanks in advance.

RE: Motor Control/Sensor Question

Usually made with a constant torque motor. DC or AC. That or a WRIM with an external resistor.  

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: Motor Control/Sensor Question

Well, how big of a cable reel are we talking about? A WRIM on a 20 inch reel is a bit of over kill I think... tongue

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln  
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies  

RE: Motor Control/Sensor Question

Gunnar also mentioned a torque motor which would be appropriate for a 20" reel.  

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Motor Control/Sensor Question

Trying to find that 20 inch spec in the OP. But cannot...?

Seen WRIM on indoor gantry cranes. Not very big ones.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: Motor Control/Sensor Question

I didn't say it WAS a 20" reel, I was using that as an example in pointing out that we had no frame of reference for the discussion. Are we talking about a 20" shop cable reel or a 20ft undersea communications cable reel?

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln  
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies  

RE: Motor Control/Sensor Question

So, I am not blind? I was getting worried.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: Motor Control/Sensor Question

(OP)
Thank you all for your input!  The reel is 24" O.D. 4" wide.....with 1500-2000' of 1/8" nylon sleeved 7x19 strand aircraft cable.  unwind/rewind at rate of 60-80 ft/sec.  load on end of cable not to exceed 250-300lbs.

RE: Motor Control/Sensor Question

That sounds more like a winch application then a cable reel application.
A cable reel doesn't usually pick up a load. It is used to pay out or recover a cable as a machine such as a gantry crane travels back and forth on its tracks. The tension developed by the torque motor or WRIM is enough to ensure reliable recovery of the cable without being so great as to damage the cable. The motor determines the tension on the motor, there is no conventional load. The end of the cable is anchored.
Although your group may refer to the device as the "Cable Reel" you may be better to consider this as a winching application when asking for advice. This application looks like a 50 HP or greater winching problem.
Have you considered an induction motor with a Variable Frequency Drive? That will give you smooth controlled speed and acceleration/de-celleration and extra breakaway torque if you need it. A WRIM may also be suitable but will not give as good control when lowering the load.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Motor Control/Sensor Question

It is very likely to damage the cable by wind directly onto it under such high tension. The cable at the core will be crushed. In this type of application the main tension is applied by capstan rollers. These rollers do not change diameter like the reel. This also allows the motor to be much smaller. In your case 50 HP is the minimum.

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