Author Topic: Starter motor for grain mill  (Read 3096 times)

Offline gmac

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Starter motor for grain mill
« on: October 11, 2012, 08:28:57 AM »
 I have a heavy starter motor that I'm thinking of using for a grain mill.  Obviously it has substantial torque but I'm not sure about the run time.  I don't think 12 V starter motors are set up to run for an extended period of time but I'm not sure if the 5 to 10 minutes needed for grinding a batch of beer would be too long.  It would need to be geared down to get near the 200 RPMs needed for a grain mill but that shouldn't be a problem.
Has anyone used a starter motor for a grain mill?   

Offline jeffy

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Re: Starter motor for grain mill
« Reply #1 on: October 11, 2012, 08:54:37 AM »
Most car starters will turn about 250 rpms when turning over an engine.  With no load, that would probably triple, I'd guess.  You could always increase the pulley size on the mill to slow it down.  The less load the longer the run time.
Jeff Gladish, Tampa (989.3, 175.1 Apparent Rennarian)
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Offline hopfenundmalz

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Re: Starter motor for grain mill
« Reply #2 on: October 11, 2012, 09:11:34 AM »
Jeff is right, if you crank an engine with the spark plugs out, it spins much faster.

Starter motors are sized for the worst case, and are for a short time of high output,  then they can overheat if over worked. I don't think the mills that we use will have anywhere near the torque requirements compared to an engine, which means the current will be much lower, and the run time can be longer.

Jeff Rankert
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Offline anday6

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Re: Starter motor for grain mill
« Reply #3 on: October 11, 2012, 10:39:45 AM »
Also, starter motors heat up VERY quickly and likely wouldn't last very long when submitted to constant running.

Offline hopfenundmalz

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Re: Starter motor for grain mill
« Reply #4 on: October 11, 2012, 10:41:10 AM »
Also, starter motors heat up VERY quickly and likely wouldn't last very long when submitted to constant running.

True, as that is the limit when cranking - you can burn up the motor. At a lower duty cycle, how long do you think it could go?
Jeff Rankert
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Home-brewing, not just a hobby, it is a lifestyle!

Offline jeffy

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Re: Starter motor for grain mill
« Reply #5 on: October 11, 2012, 12:52:48 PM »
Also, starter motors heat up VERY quickly and likely wouldn't last very long when submitted to constant running.

True, as that is the limit when cranking - you can burn up the motor. At a lower duty cycle, how long do you think it could go?

The harder it has to work, the more resistance it will take, the hotter it will get.  With little resistance, using it to turn a grain mill, I think it would be OK. 
I use a treadmill motor to run my mill.
Jeff Gladish, Tampa (989.3, 175.1 Apparent Rennarian)
Homebrewing since 1990
AHA member since 1991, now a lifetime member
BJCP judge since 1995