Buffalo Tumbler, Gear Ratio Reducer 1

[AIRFRAMER]

Hello,
I built a Tumbler for Large Hides, Buffalo, Elk etc. The
tumbler is like a dryer, it is 6'long, 6'wide, making the circumference 18'. It is made with 2*4's & 3/4" plywood on the sides, I have it on a Metal Frame with Pillow Block Bearings on the sides for rotating, I am trying to use a Baldor 1.5 HP Electric Motor Single Phase, Farm Duty with 1725 RPM. I need to slow it down to 18 to 20 RPMs. I used a 1.5" pulley on the motor shaft & a 4'pulley (12'circum), on the tumbler itself and it still won't slow down, we tried to connect it to 120v kept popping circuit breakers, connected it to 220 works fine just can't seem to get it to slow down. The hides are pretty heavy also and i have to put in at least 150lbs of saw dust to help break the hides.

 

[jraef]

Please don't cross post a question intended for another forum without first considering your audience. Your duplicate post in the Gear and Pulley Engineering forum is the correct place for this question. If you wanted to know if you can somehow make that motor slow down, you would have needed to ask that specific question.

Now, assuming that is what you meant, the answer is no. Single phase motors cannot, for the most part, be slowed down electrically. Your best bet is to do this mechanically to be honest. Technically there are variable speed drives for single phase motors, but they will not work on that motor.

Anticipating possible further questions:

1) Your best electrical approach may be to use a slower motor to start with, such as a 6 pole motor (900RPM synch. speed), which will turn ~850RPM depending on slip. Then your pulley ratio will not need to be so high.

2) Another theoretical option (since you would need to replace that motor anyway) is to put in a 3 phase motor and get a VFD to operate it. VFDs can convert 1 phase to 3 phase easilly in that HP range. The drawback to that is that you may have trouble running the motor continuously under a heavy load at really low speeds, so you still need to play with your pulley ratio. If you are going to do all that, it only makes sense if variable speed means something to you. If not, I'd recommend just doing it all with pulley reduction.

JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
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[itsmoked]

Put in a jack-shaft and you get to multiply the reductions and avoid lousy 1-1/2" pulleys that will be forever causing you problems.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

I'm with itsmoked here. Use a jack shaft.
yours

 

[jraef]

Yes, I hope that came across in my post too. Although I was expounding on electrical ways to do this, you are most likely better off doing it mechanically.

JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> faq731-376

 

[waross]

If you run a 3" pulley on your 1725 RPM motor to an 18" pulley on the jack-shaft, the jack shaft will turn at 287.5 rpm.
A 3" pulley on the jackshaft to the 48" pulley on the drum will turn the drum at 17.97 RPM.
The jack shaft is winning 3 votes to nothing. Go with it.
yours

 

[itsmoked]

I really have my doubts that 1.5hp will even do that load. The tannery I advised had, hmmmm 20? Of these type devices. They were called "re-tanners" if they were filled with hides and water and dye. They were called "dry mills" if they were for breaking down the hides, making them fluffy soft. They had a retanner for prototype loads that was a wooden barrel 24" wide and 48" dia. I think it had a 3hp 3ph motor running it at about 20RPM. The larger retanners 8ftx14ft ran 50-100hp with/without VFDs. The dry mill was 8ft wide and 10ft diameter with about (30) 3" dia pegs inside it that were 24 inches long. It essentially beat the cr*p out of the leather. It used 15hp. So my thinking is you need more than 1.5hp to lift that load while it essentially lays on the "uphill side" with that moment arm. But that is just a guess.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com