Compressor duty motor??

R

rlinger

Joined
Mar 29, 2002
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I'm still going round and round deciding which way to go for a motor for the Coote I'm about to order. Itrade's DC motor route seems good to me but I don't know about putting out 200 plus dollars for that combination right now and I can always change the motor type and control later. Now I'm back to looking at AC motors. I'm looking at a 1 1/2 hp for 120 bucks (probably an import but it is enclosed and stated to be continuous duty and 1750 RPM max.). This motor is classified as a 'compressor duty' motor. I don't know much about motor classifications. Is that a bad choice for my grinder?? I can get the same thing in 1 hp for 100 bucks and there is a 'farm use' 1 hp for a little less. I'd like to get one a little heavier than 1 hp, I guess.

Thanks;

Roger
 
A "compressor duty " motor is designed for applications requiring high startup and breakdown torque. It should work fine for a grinder.
"Farm duty" motors are pretty much the same thing but are usually totally enclosed.
Motors tend to overlap in regards to applications.
Regards,
Greg

Forgot to add: lot of good info on motors here.
 
I'm useing a Coote 2x72 with a 1 horse farm duty motor with good results. I have several farm duty motors in my shop and had good service from them.

The only thing, my Coote will bog down a little if your realy hoging, like cleaning up a damascus billit. I will go to 1 1/2 horse if this one ever burns up. You can also get step pullys to change speeds. Although a varible speed would be great.

I may be mistaken, but I was under the impression that a compressor duty motor was not built to handle contenus running.
 
I may be mistaken, but I was under the impression that a compressor duty motor was not built to handle contenus running.
Click to expand...
Hi Will,
That is true with some motors used on compressors.
However it is dependant on what duty rating the
motor has.
Regards,
Greg
 
Ripper, (and thanks to both of you fellows)

What is ment by 'breakdown torque'??

BTW, they state that these compressor duty motors are enclosed but the farm use is not. These are made by Chicago. Relatively cheap by comparison I would guess(?).

Ripper, thanks for that link. They state continuos duty for these two 'compressor duty' motors. This particular farm use motor is stated to be NOT enclosed.

Will, I am getting a set of stepper pulleys with the Coote.

Roger
 
Hi Roger,

I edited my previous post to include a site with good info on motors.
Here is their explanation of 'breakdown torque': "The maximum torque a motor develops under an increasing load without abruptly losing speed and power. This is sometimes called pull-out torque"

BTW, they state that these compressor duty motors are enclosed but the farm use is not. These are made by Chicago. Relatively cheap by comparison I would guess(?).
Click to expand...
I don't think there are any set rules in that regards, my "compressor duty" motor is not totally enclosed.

Is your motor the one Harbor Freight offers? I've had good luck with their motors.

Regards,
Greg
 
Ripper,

I haven't scrolled up to see your edit yet, but will after this writing.

Thanks for the explaination of breakdown torque. I see the picture and like that.

I was about to edit my last post and admit that - yes - they are Harbor Freight. I am glad to hear you are satified with those that you have. I too have a couple and, in particular, my metal cutting bandsaw has been a great tool and just as good a buy.

Now to look at your edit....... NOW I AM EDITING THIS POST: Great. Thanks. I put in my favorites to study tomorrow. Another item of interest might be that they state, for all three of these motors, they are reversable.

Thanks;

Roger
 
first let me admit that i know very little about motors.

NOW, yesterday i saw several motors at Tractor Supply. made by GE, from 1/2 HP - 5 HP and topping out at $160 or so. They were all enclosed motors that ran one direction only. but really, they were pretty cheap. i think they are primarily used in agriculture type situations, but hell...thats about as dirty as it gets. and its a GE instead of a China direct from Harbor Freight.

i dunno, but if it were me, id prolly go with a motor from Tractor supply.

ive read in several places that the Harbor Freight motors are rated higher than they actually perform at. (ie, a 4/5 HP motor acts more like a 1/2 HP motor) - this is from the mini-mill and lathe folks...

EDITED TO ADD: i believe these were rated as continuous duty motors.
 
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