Windscreen Wiper Motor For Mash Stirrer

[Hogan]

Looking at options for powering my mash stirrer. Some brewers have used a windscreen motor for its low revs and high torque. Are they much of a muchness or is there one car model that best suits?

Also.. anyone used a computer power pack to run the 12v wiper motor. If so, set-up info or pics would be appreciated.


Cheers, Hoges.

 

[Justin]

Hi Hoges,

I've used a windscreen wiper motor to power my Barley Crusher but not stir a mash. I can't really tell you if there is much of a difference between them sorry. But as a side note, for a power supply I ended up using a 12V battery charger from Supercheap Auto (it was about $10-$15 if I remember rightly). I had to get one with a 10amp fuse as I had another charger with a 5amp fuse and it would blow it on occassions. So it must be kind of testing the charger a bit but it's been working brilliantly.

Anyway my point is, be aware that they can draw a bit of current so factor that into the computer power supply you choose. I dont know how many amps you can draw on a computer power supply (I know they vary) but I'd say you would need at least 5amp, preferrably more to safely drive the motor under a heavy load. It is the start up that will get you most likely.

Sorry, don't know how to hook up a comp power supply. I did look into it and it's quite easy but I went the charger route. There is plenty of info on Google on how to use/wire a comp power supply.

Good luck, Justin

 

[tk75]

Just a note on the PC power supply...you will need to make a switching circuit to switch the supply on. They don't just switch on when power is applied from the mains, the power becomes active through the motherboard.

The best option would be go for a battery charger from an autoparts store and get one around 20AMP.

 

[Sammus]

http://www.wikihow.com/Convert-a-Computer-...ab-Power-Supply

 

[Yorg]

I decided to use a rotisserie motor.
If it can turn 40Kg of Lamb, it can stir your mash.
Plugs straight in to mains, no mucking about with circuitry.
Nice self contained box.
Guy I bought it from sells them through ebay, and will custom make the right size bush for you.
I drive a 1/2 inch copper pipe as a drive shaft, so he made me a bush to couple straight on.
OK, it was $110 delivered.

Cheers.

 

[Zizzle]

I have some windscreen wiper motors in the brewbot, and they have stall current of 2.5 amps, and a free running current of 1.2 amps. Some others do draw more however.

As for the PC power supply, just connect the green and a black wire wire on the big ATX connector and it will fire up. Take your 12v from the yellow & black. Most modern ATX supplies should be good for at least 8 amps from the 12v rail, so plenty for a wiper motor.

 

[Zwickel]

As for the PC power supply, just connect the green and a black wire wire on the big ATX connector and it will fire up. Take your 12v from the yellow & black. Most modern ATX supplies should be good for at least 8 amps from the 12v rail, so plenty for a wiper motor.

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It depends what kind of powersupply you can get. The very old AT-Powersupplies are provided with a hardware switch, (easy to start, just switch on) the newer ATX-Powersupplies have a kind of software switch, green line to ground.

But...dont start it without any load, the powersupply needs a load at startup.

Most of 12V rails can deliver typically around 15Amp., would be more than enough.
But it would be recommended to bundle many of the 12V-wires. In case your motor
sucks many Ampres, a single wire would be too weak.

Cheers

 

[Hogan]

I decided to use a rotisserie motor.
If it can turn 40Kg of Lamb, it can stir your mash.
Plugs straight in to mains, no mucking about with circuitry.
Nice self contained box.
Guy I bought it from sells them through ebay, and will custom make the right size bush for you.
I drive a 1/2 inch copper pipe as a drive shaft, so he made me a bush to couple straight on.
OK, it was $110 delivered.

Cheers.

Yorg - Is this your link - are you satisfied that 15 rpm is sufficient for the stir arm to keep your grist from too much direct heat at the bottom of the tun?

Thanks to all who have provided advice and guidance on this thread. All ideas being considered.

Cheers, Hoges.

 

[fraser_john]

I too have been looking at this. From what I have experimented with, a Ford XD wiper motor runs around 90 rpm, which is about twice as fast as you would want to stir the mash. RS Australia sells timing belts and gears that would work great for this, a 10 tooth and a 20 tooth pully would drop it down to about 45 rpm, which would be perfect. I think one of these wiper motors delivers about 9Nm of torque, so after gearing it down it would be 18Nm which is tons for grain stirring.

I just need to find someone with a lathe to turn my 3/8" shaft down to fit an 8 or 6mm timing pulley!

 

[Yorg]

Yorg - Is this your link - are you satisfied that 15 rpm is sufficient for the stir arm to keep your grist from too much direct heat at the bottom of the tun?

Thanks to all who have provided advice and guidance on this thread. All ideas being considered.

Cheers, Hoges.

Yes that's the link.
I'm not using a direct fired mash tun, I'm stirring to evenly distribute heat from steam injection.
Have you seen the article in the Brewing Techniques magazine archive:
http://brewingtechniques.com/library/backi...sue2.6/put.html
I think the paddle design - at least teh lower part of teh paddle - would be useful in a direct fired tun.
Probably the rotisserie motor would be too slow, though you could use a belt and pully to 'gear' it up and still have loads of torque to spare.
Cheers.

 

[tangent]

don't forget some old crazy VW's ran on 6V if that makes it easier.