Balancing Belt Tension

[agrico]

We have a moving shiploader boom with cover reels on both ends. As the boom shuttles through a cradle one reel pays out and the other reel pays in. We are trying to balance the two reel forces to not overpower the motor that actually pushes the boom.

 

[davidbeach]

Sounds like a good idea; is there a question lurking in there somewhere?

 

[agrico]

To clarify, the question is how to program the two reel drives to stay in tension and remain balanced (another complication - the diameter of the reels is always changing)

 

[magoo2]

You'd do better posting this under Mechanical engineering. The transmission piece of this forum deals with transmission lines not with mechanical transmissions.

 

[PHovnanian]

What davidbeach said. The motor that pushes the boom (singular) will drive whatever mechanical load its connected to. If there's more than one motor involved (one on each reel), there might be an electrical solution (VFDs modulated by tension sensors, etc). But your setup sounds like its in need of a mechanical solution. Possibly running the cables several turns around a constant diameter drive wheel. Or driving both drums through some sort of differential gearing from the one motor. Something us EEs happily ignore once our motor shaft disappears into the nether world of grease and pulleys.

 

[agrico]

One more clarification, attached is a picture of one of the 15 hp cover reel drives.

 

[itsmoked]

Wow. That's really hanging it out there.

Please tell us some more. What's the thing on the left end of the motor shaft? A brake?

Is there any kind of friction clutch lurking in the system?

What VFDs are you using?

Do you have position encoders?

The more you flesh this out for us the more likely it will paint a solution into one of our minds. The picture was a big help be not enough.

Can you explain the mechanical situation with more detail? I'm not clear on how these drives would battle with the boom drive.

We're EEs here so don't assume we know what a "cover reel" is.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Now that you have started in this forum it may be well to post short questions in both the mechanical fora and the "Electric motors, generators & controls engineering" asking the readers to check and answer in this thread.
Posting the same question in multiple threads is frowned upon, but a "Heads-up" asking the posters in other fora to look at this thread is acceptable.
Have you done an evaluation on how much variation in tension is allowable? I expect that tension is not critical as long as there is enough to move the machine. A wide tolerance may make the solution easier simpler and cheaper.

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