Grinder build - motor help

D

DukeHarley

Joined
Apr 11, 2014
Messages
644
Ok I need some advise. I'm building a GIB 2x72. I've got all but my drive wheel, variable speed control, and motor. For starter lets be clear that I'm an idiot when it comes to electrical and motors. What I'd like to do is buy a big enough motor to run on 220 in the future when i can afford to remodel and upgrade the electrical in my garage.

So for now id like to be able to run it on 110 using a variable speed control. I think I saw somewhere that I can run a 2hp motor and a KBAC-27d on 110 but it will only produce 1.5hp. Is this correct? What specs other than 2hp should I be looking for in a motor? Some say get a 1700rpm and I've seen others say 3400rpm. Am I correct in thinking the 1700rpm would be better for torque?

Other than hp and rpm what specs am I looking for? I guess what I'm looking for is someone to say "this is the motor you need to do what you want to do".

Thanks in advance guys!

Jay
 
Well, this is what I used to build mine based on all the information here:

2HP 1725RPM 56C TEFC 3PH MOTOR

This is what I got- but note that it doesn't have the stand, just uses the face mount for GIB

http://www.electricmotorwholesale.com/index.cfm?fuseaction=product.prodInfo&prodId=6265

And Yes, with the KBAC-27d you are looking at- and I also got- you will be able to almost double the speed, and use it on 110v at 1 1/2 hp until you get your 220v line in. You will still need to make sure your outlet at 110v can provide the amps safely that this will require.

I am loving my new GIB and 2hp is a very strong motor combined with a 36grit belt for hogging serious steel!

Oh, and I went with the 5" drive wheel and 4" tracking wheel- working great!

Good luck,
Stuart
 
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The idea of de-rating a 2hp to 1.5 hp isn't really as effective as using the correct size motor to start. "IF" you've go a dedicated 30 amp, 120vac circuit you can make the 2ph work. Otherwise, you're pushing it.

"IF" you only have 120vac I'd seriously think about using a 1hp, or at max a 1.5 hp motor. There is a 3 ph Iron Horse TEFC motor for around $125 or so shipped, size ranging from 1hp to 2hp.

Ken H>
 
Jay, I did not want to install a 220 line in my garage so I used a 1 1/2 hp motor for my grinder for a year....then sold the motor and bought a 2 hp motor and had the 220 box installed which I should have done in the first place. The electrician was done in no time and it cost a lot less than I expected. I now have a second grinder which is a 2 hp also and I use the same plug in for it. Larry P.S. A 5 inch drive wheel on a 1725 RPM motor will not produce a very high speed (in my opinion) so I bought a 3450 RPM 2 hp Leeson and used a 4 inch drive wheel. It produces 3690 Surface feet per minute and is plenty powerful. LL
 
IF the motors are the same HP rating, the 1750 RPM will have twice the torque af the 3500 RPM motor when running at 1750 RPM.

In the vast majority of cases, a 1750 RPM motor can be driven at 120 Hz to run at 3500 RPM or thereabouts, because the only difference between the 1750 RPM and 3500 RPM versions of the motor is the windings, which are static anyway. All the rotating bits are common to both speed variants.

The 3500 RPM and 1750 RPM motors will both have the same torque when running at 3500 RPM.

You will therefore get the same top speed (3500 RPM or thereabouts) and a lower usable bottom speed on a 1750 RPM motor (most VFDs will drive a motor smoothly down to 10 Hz, but going below that they tend to feel "coggy" in my experience).

 
Ok then if I were to go to a 1.5hp motor can I still use the same controller for the 1.5 for now then just swap out motors when I get my garage rewired down the road in a year or two?

I'm not opposed to buying another motor down the road as I can alway use the 1.5 on another project like a disc sander after I swap them out. I'm not to concerned about the future I just want to know what's the best route operationally for right now. I've been using a filing jig now since May/June for my bevels and to be honest it is terribly time consuming and I'd like the best motor for right now to get up an running for what I have as far as power.

You guys have no idea how much I go to this site for guidence and just want to say thank you to all those out there that contribute to this site. Thank You guys!!!!

Jay
 
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