Will this Blower motor work for grain mill?

[cank]

I have a 3/4 HP blower motor that I want to use for my new MM2.2 Mill.
On the wiring diagram it has 3 speeds but I don't know if using the lowest speed will drop the HP and torque too low. I also have not been able to figure out what the actual RPM would be at each of the speeds to know what size pulleys to get.

Here is a pic of the label:

 

[stpug]

I am not a mathematician, nor a physics guru. This is the best I could determine but would need to be confirmed with someone smarter than me

HP 0.75
RPM 1075
Should yield ~40+ in. lbs of torque, as-is.

It is a single phase motor and should have a capacitor, which is the correct type of motor for milling grain.

It is the correct type of motor and, at full speed, it should have enough torque to mill your grain. Of course, 1075 rpm is probably WAY faster than you would want.

Assuming you want to mill around 175 rpms then you would want a 1.5" sheave on the motor and a 9" sheave on the mill. Dropping the rpms on the grain mill will increase the torque, which wasn't a issue before and is even less-so now. Basically, an 8" sheave will give about 200 rpm, 9" about 180, and 10" 160 rpm - as long as your motor sheave is 1.5".

Hope this helps.

 

[hedbutter]

What kind of blower motor is this exactly?

 

[cank]

Thanks for the reply.

It's from an AC shop and I think it came out of an AC unit.

It has three speeds that I can wire up and I found somewhere that the lower speed reduced HP but it was a vague post and I can't find it anymore.

Also, what exactly is the formula for torque? I've seen several examples but each of them use a different constant.

 

[stpug]

I used the equations at the bottom of the following page:
http://www.engineeringtoolbox.com/electrical-motors-hp-torque-rpm-d_1503.html