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Fleece tumbler - its a sheep thing!

Advice needed on single phase speed controllers

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Tony Read 223/06/2015 13:42:06
965 forum posts
3 photos

My wife wants me to build her a fleece tumbler to get all the nasty bits out of a sheep/alpaca fleece before she spins it. Something similar to this:


She wants it motorised (the guy building the one above fitted a dryer motor). I was thinking about a washing machine motor. It needs to spin from about 15 rpm to about 5 rpm so will need pulleys to gear it down and a speed controller with on/off. Not too hot on speed controllers so would appreciate any advice on how to go about it.

Frank Skilbeck23/06/2015 16:55:01
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4730 forum posts
101 photos

A washing machine motor is basically an AC induction motor, which means it's speed is linked to the AC frequency so you need a variable frequency drive to make it work, I've used these on 3 phase motors but never on single phase motors so I'm not sure if such a device exists.

ROY DAVIES 123/06/2015 17:28:02
139 forum posts

Tony you should go green and hook it up to a bike or maybe an alpaca. have a Google at 'model engineering lathes'. They have a good section on motors and drives plus a selling section plus eBay of course there are quite a few there, Try this link if it will work. **LINK**

If you fit a 3 or 4 speed pulley to the basket shaft and a small multi 'v' ( one size ) to he motor it will drive under the weight of a pivot mounted motor you would have a fairly decent speed range for little money. Machine Mart sell ali pulleys. They used to be made by 'Picador' If you are near a transmission outlet - for belts chains an so on they would be able to help there are pulleys that use taper collets and an Allen screw to nip them up on a shaft, come in a large variety of sizes

John Olsen 124/06/2015 06:54:50
446 forum posts
23 photos

The usual VFD (Variable Frequency Drive) is meant for three phase motors. They are not too expensive these days but you do need a three phase motor. If you are buying a motor new a three phase one is likely to be no dearer and quite probably cheaper than a single phase one, but of course you are not so likely to be able to salvage one out of an old washing machine. You may be able to get one from the sort of place that sells second hand machine tools or even from a computer scrap outfit.

John

vic evans 124/06/2015 08:17:52
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34 forum posts
5 photos

Maybe I'm being too simplistic . If you are using bike wheels for bearings why not fit one with a tyre & turn it with a friction 'wheel' on a motor. I haven't calculated the gearing ie diameter of motor 'wheel' but maybe even a tapered drive on a sliding motor to vary the revs.

Edit. A quick check seems to indicate a 1" - 1 .5 " dia motor 'wheel' @ 1450 rpm against a 28" dia bike tyre would be in the ballpark. However I'm in a rush & these figures could be rubbish

Tony Read 224/06/2015 12:52:34
965 forum posts
3 photos

Vic, you are a genious! I think that that is how the guy did it with a dryer motor and a belt to a pully friction driving the bike wheel.

I wanted cheap and cheerful but with speed control, after all how hard could it be? There are loads of appliances/tools that have speed control, washing machines, sewing machines, drills etc, how is the speed controlled with these?

Would a 12v motor be easier to speed control?

One wag at work suggested a sheep in a hamster type wheel powering it. teeth 2

kc24/06/2015 16:49:48
6514 forum posts
173 photos

Why not use an old tumble dryer or at least the mechanical bits?

John Olsen 129/06/2015 07:14:30
446 forum posts
23 photos

Most of the smaller devices that have speed control, like drills, sewing machines etc have universal type motors in them. There is nothing to stop you using a motor of this type, although they might be at the low end of the power range that you want, and not all are meant for continuous operation. A drill for example might not take kindly to being run continuously. Universal motors can be speed controlled with a relatively simple controller.

Washing machines are another story....Fisher and Paykel here in NZ pioneered the use of a permanent magnet three phase inverter motor in washing machines. This makes the whole thing a close cousin of the type of thing we are using in model planes these days, but a bit larger. (Not necessarily more powerful!) The earlier motor was similar in appearance to a normal style of mains motor with a belt drive but the later ones are a multipole machine with direct drive to the washing machine drum. They are very popular with the self sufficiency guys as they make an ideal alternator for a windmill to drive, since they can generate at quite a low speed. As a motor, they can run very slow for the washing cycle and very fast for the spin. They would be ideal for what you want except you would still need a VFD, or else enough electronic knowledge to repurpose the inverter from the machine...which would not be easy.

You might look out for information on rock tumblers..they are a bit smaller but have similar speed requirements.

I wonder myself if just having a couple of pulley sizes on a countershaft would provide enough speed variation. That would allow the use of a simple motor salvaged from a washer or drier. You would have to stop to change speed but I can't see that being too much of a problem.

Are the alpacas good eating? I suppose there are quite a lot of neck chops.

John

Tony Read 229/06/2015 13:52:40
965 forum posts
3 photos

Thanks John, very informative.thumbs up

I've come to the conclusion that it's not so easy to control the speed of larger motors as I thought. Its a bit like getting a modern car engine to run when you don't have all the electronic gismos attached.

I did find this guy here. He could be my salvation!

Are the alpacas good eating? I suppose there are quite a lot of neck chops. teeth 2LOLteeth 2

John Olsen 129/06/2015 22:48:56
446 forum posts
23 photos

Hi Tony,

That looks quite promising, provided you use it with the correct type of motor...it is quite a different type to the ones here in NZ, but I guess must be common enough over there. You will of course need to pay attention to mechanical and electrical safety if you put together something like that.

John

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