Grain Mill motor torque Question/help

[carkom]

I need some help figuring out my grain mill motor ratios. I have a treadmill motor. It doesn't say what the HP is for the motor on the sticker. Any way to find this out? Do I need this info to find out if I'll have enough torque?

I have all the inards that went with it. It's variable control and works fine. Another issue is finding the right RPM since I have no way to measure it. The only thing I know is that at max it's 4800RPM which is way too fast.

 

[30Bones]

If it's variable speed, why not go direct drive if you can get it down to low enough rpm's (300ish)

 

[carkom]

At that low of RPMs the torque isn't enough to grind the grain.

 

[Stealthcruiser]

I have not utilized my treadmill motor as of yet, but it's specs show 7, yes 7 HP!
It's a DC motor, with the power supply and speed control circuits.

I din't have a mill yet, but I'm guessin' it would have no trouble starting with a loaded hopper, and then dialing down to milling speed and maintaining it.

It came with a "ribbed" belt on it, with a 1 inch drive pulley, to a 2 inch driven roller, so not much torque multiplication going on there.

Also, it is equipped with a 6 inch flywheel incorporating said drive pulley.

 

[Puddlethumper]

Run it full speed. Put a big pulley to the mill and a small one on the motor. Use it's best torque output and gear it down to the rpm you want. Gearing it down will give you even more torque at the mill shaft.

 

[audiophool]

If I am reading the label correctly, this is a DC motor - don't plug it into a wall outlet directly. 90 volts at 15 amps is 1,350 watts, which would be just under 2 HP if it were 100% efficient. Say 1-1.5 HP in real life.

 

[DanVSTL]

A member of our club turned a old treadmill into a mill. Very heavy.

 

[Puddlethumper]

If I am reading the label correctly, this is a DC motor - don't plug it into a wall outlet directly. 90 volts at 15 amps is 1,350 watts, which would be just under 2 HP if it were 100% efficient. Say 1-1.5 HP in real life.

I used to have a 1.5 hp motor on a table saw. That was at 1750 rpm. Gear it down to 300 rpm and you've got plenty of torque to turn a grain mill.

 

[carkom]

Run it full speed. Put a big pulley to the mill and a small one on the motor. Use it's best torque output and gear it down to the rpm you want. Gearing it down will give you even more torque at the mill shaft.

Thanks for all the responses. Everyone mentions running at the rpms I want. Which would be great if I had any way to know what the RPMs are. The variable control knob changes the rpms of the motor but I don't know what either the motor or the mill would be running at. putting the motor at full (4800) would mean I'd need some crazy 20+" pulley to get the mill down to 300 RPMs.

Putting the control knob at half turn doesn't seem to be half the motor speed so I can't really even guess. Do I just need to use an RPM strobe tachometer (stroboscope)?

 

[Puddlethumper]

Putting the control knob at half turn doesn't seem to be half the motor speed so I can't really even guess. Do I just need to use an RPM strobe tachometer (stroboscope)?

If you could get your hands on a strobe that would definitely be the best thing. But you can probably guestimate it fairly closely if you fiddle with it a bit. I don't think that 300 rpm target speed is chiseled in stone, anyway, so if you can get it slowed down to a speed that seems to be turning about right you'll probably be OK.

Depending on the size mounting platform you have to work with I think I'd get as small of a drive pulley that I could find that would fit the motor shaft. Then as large a driven pulley as will fit the shaft and space available. Hook it up and run it and see how it does. You can always tweek the speed down if you need to.