42 replies to this topic

[portfire]

anyone reccommend a washing machine

Yeah..Me Thats what I use and depending on other factors, you can have VERY fast meal (just like me) in 30 mins Dam my mill kicks ass LOL

[digger]

It's not certain that a motor for a low duty application like a lawnmower will be good in continuous use. There is no indication of motor speed. You could not likely run it at a ball mill speed for long without overheating.

I would not count on that Arthur, A lawn mower would have a large load upon it in duty, hence in a low energy application such as a small ball mill it would draw next to no current relatively. Being a DC motor it is very easy to slow down. Also it would appear that the motor is from a rotary type mower and would hence have a lower RPM than a direct drive type.

I am not saying that that is the best ever motor to use. But it is certainly a heavy duty motor capable of continuous duty judging by its size and weight (a lawn mower would undergo extensive continuous testing before it went to market, they would not sell many if every time you cut a big lawn the motor burnt out, long grass etc).

Although it is wise to know how to wire it before buying. It is better to go for a motor and inverter / controller package and they do come up for less than £25 - £30.

Edited by digger, 17 October 2008 - 06:45 AM.

[digger]

I have just bought an inverter on ebay, it is a little more than I have paid in the past. However it is still good value for a variable speed driver for an AC motor. All I need now is a standard motor to match up with it so I can knock up a variable speed star roller to go with the mill.

Clicky Clicky

Edited by digger, 17 October 2008 - 06:45 AM.

[dr thrust]

hoo!, thats just the sort of thing i need to slow down my mill to optimum speed, how do they work? and ease of wiring up?

[digger]

hoo!, thats just the sort of thing i need to slow down my mill to optimum speed, how do they work? and ease of wiring up?

They just change the frequency of the mains supply (infinitely variable between a couple of Hz and 120hz). So half the frequency half the speed of the motor. They are easy to wire up (well the model I have bought is). There is only one thing to really watch out for and that is if you run a motor slower and it is under a heavy load then it will heat up more than normal for a number of reasons including the motor fan not being as effective. So these controllers have the facility to include a thermistor for thermal monitoring. However from experience this is not necessary in our application unless you are trying to turn a massive mill jar (think 70Kg or more kg on a 1/2 hp motor given a sensible turn down, I would imagine 10kg - 15Kg of media is the max most would use to make their 100g of meal very quickly).

Oh yeh and they can do clever stuff like slow start.

Edited by digger, 17 October 2008 - 07:06 AM.

[dr thrust]

haa i see thanks for the inverter lesson i see the one you have bought is rated 0.4kw what size motor would that run? 1/4 hp? thats what ive got, but its way to fast at the moment even with different pulleys ect

Edited by chris m, 16 October 2008 - 11:06 PM.

[digger]

haa i see thanks for the inverter lesson i see the one you have bought is rated 0.4kw what size motor would that run? 1/4 hp? thats what ive got, but its way to fast at the moment even with different pulleys ect

1/2hp or less (1 hp = 746 Watts)

Edited by digger, 16 October 2008 - 11:09 PM.

[dr thrust]

thanks digger but your answer was to fast! you didn't give me time to correct my spelling

[digger]

Hows that?

[dr thrust]

great nobody will ever know

[digger]

Yeah..Me Thats what I use and depending on other factors, you can have VERY fast meal (just like me) in 30 mins Dam my mill kicks ass LOL

So how is your washing machine modified for use as a mill?

[xXPyroJoeXx]

Thanks for the replys guys...so um how effective is a washing motor, if thats the only thing I can get my hand on? But perfect would be a tumble dryer motor as it is one speed and doesnt require any complex wiring etc. Also, hows a wheelchair motor sound?

Thanks

[portfire]

So how is your washing machine modified for use as a mill?

Basically took the thing apart. Motor, belt and the pulley off the back of the drum (quite hard to remove). Made frames out of MDF to support motor and the rollers (made them, quite easy). I started with 1.5" rollers and ended up with a 4" drive roller. without the math, it's turning the jar at around 95 RPM. I'm using a 1.3lt jar and 1Kg of ceramic media, I only mill in 50g batches.


I'll add though for others.. If you think your mill is not preforming as it should, experiment with the batch size.

Edited by portfire, 17 October 2008 - 05:05 PM.

[xXPyroJoeXx]

Basically took the thing apart. Motor, belt and the pulley off the back of the drum (quite hard to remove). Made frames out of MDF to support motor and the rollers (made them, quite easy). I started with 1.5" rollers and ended up with a 4" drive roller. without the math, it's turning the jar at around 95 RPM. I'm using a 1.3lt jar and 1Kg of ceramic media, I only mill in 50g batches.

But how did you modify the fact that a washing machine has different speeds?

And it works ok yeh?

[portfire]

But how did you modify the fact that a washing machine has different speeds?

And it works ok yeh?

With modern machines the speed can vary, with the motor having lots of wires or a inverter. Look for a old-ish motor. The one I have has 4 live (brown) wires, 2 for forward speed, fast & slow and the same for reverse. All I did was find the wire for the slow speed......Just be careful...Risk of electric shock!, which I think common sense will mitagate the risk there