KMG motor... specific question

silver_pilate

silver_pilate

Joined
Oct 30, 2002
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This may be a no brainer, but no one ever accused me of having a brain. I ordered my KMG today with several goodies including the base plate. I did not order a motor or motor pulley, and instead, I am piecing together my own motor/VFD combo and building a clean box with face panel controls.

Now I'm looking at the motors from Grizzly's outlet store, and I have a choice between the 2 hp 3 phase TEFC spinning at 3600 rpm and 3 hp 3 phase TEFC spinning at 1800 rpm for the same price. Any thought's on that?

Also, since I ordered the base plate for the KMG, I'm curious as to if anyone knows the hole spacing for the motor mount. The 2 hp is 3"x4.8" and the 3 hp is 4.5" by 7.5". The shaft size is different as well with the 2 hp having a 5/8" shaft and 3/16" key and the 3 hp having a 7/8" shaft with a 1/4" key.

Which should I get?

--nathan
 
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Actually just read that Rob's plates are set up for 56 frame motors which I believe have a 3" spacing parallel to the motor shaft and width's vary depending on motor size. Does that sound right.

If so, I'll probably go with the 2 hp motor unless someone convinces me I need to drill new holes for the 3 hp motor.

Edited: I had asked about 3600 rpm being too fast, but I found a post Rob had made where he recommended using a 1:1 grinder to motor pulley ratio with a 3600 rpm motor as opposed to his usual 2:1.

--nathan
 
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Nathan, my brain's not working well enough to help you with all your queries... but you are right on the 56frame. 3" on center spacing.

Mostly I just wanted to say AWESOME!!! :thumbup: :D :cool: You're going to love it!!! I can already see it now... like 3 years from now you'll be posting about getting your second or third KMG! :D

As nice and clean as your shop is... you better paint that sucker with a slick paint job!!! :D ;)
 
Haha...Nick, I think I might just clear coat the thing. Gotta love the look of bare machined steel! I am PUMPED about this one.

Oh, and the shop's not so neat and clean anymore :(. It's amazing how much um.....stuff your wife can find that needs to go out there :confused: ;). Plus I just moved out of my old house a few months ago, and since we've been getting it on the market, I had to clear whatever I had left out of the house. It's mostly just piled in the shop right now, but I can still get around it all to make a few sharp pointy things until I get it all organized :D. Just remember, an organized mess is no mess at all.

Oh, and as to the question in my post, I think I'm talking myself into the 2 hp motor just because it will easily mount to the base plate, and I can run close to a 1:1 ratio to keep the rpm's under control. Unless, of course, I need that extra one hp....OH THE DECISIONS!!!

--nathan
 
with a VFD you control the speed , so I would say go with the 3600 rpm . My question would be , a DC or AC wound motor ? DC wound has better torque .
 
I had posted it before, I am rigging my grinder up with the Grizzly 2hp 3600 RPM with the 6" wheel.
 
gixxer, I went ahead and odered the 2hp 3600rpm motor from Grizzly along with a 3" sheave.

edited: Oh I see, you're running a direct drive grinder with a 6" drive wheel. In previous posts from Rob, he had confidence his KMG could handle upwards of 5000rpm at the shaft. With the 3" driver pulley and the 2 1/2" driven pulley on the grinder, it puts me at around 4320rpm through the grinder shaft. With the 4" drive wheel, that puts me at just above 4500 sfpm belt speed when run flat out.

Thanks for the tip on the motors!

--nathan
 
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Thanks Rob! Can't wait to see that machine!!

Now I've got to hobble together a control face, sealed box, and a 30' extension cord for a 4 prong 50A 220V outlet (it's what the shop has).

--nathan
 
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