Grinder Motor Question

[DoubleLung]

We finally got moved into our new place and the Mrs. has approved a knife grinder so I can keep busy this winter. I think I'm going to go with the KMG but I've been looking at motor options too see if I can buy some components seperate and save some money. From all the research I've done I think I want a three phase 2hp motor with a variable speed controler. I'm pretty green when it comes to motor knowledge and I've not had much luck finding details about specific motors people have used. When I looked at the Baldor motors, there must be 50 2hp three phase motor models! What are the specifics/features I should be looking for in a motor? DC vs AC, RPM..etc?

Thanks!

[gudspelr]

Just finished putting together my grinder.  KMG chassis with a 2 HP, 3 phase motor and a KBAC 27D VFD.  The motor is a Dayton I got off the big auction site for cheap.  Be sure to get a TEFC (totally enclosed fan cooled) motor, you have a little room for rpm's.  Mine is 1725, but with the VFD, you can change one wire and it doubles the rpm's.  It would be easiest I think if you get an AC motor, but I know a guy who has a DC, just some quirks to go with it.

One thing I'll say is if you go the KMG route with the belt drive, get a motor with the mounting plate attached to it.  I'd originally figured on a different setup and got a motor without the mounting plate (bolt to the face).  So, I had to torch/weld up a mounting bracket...

Motors can be really expensive, but if you know the things you need and the wiggle room for stuff like rpm's, you can look around and find a good deal.  Hope that helps.

Jeremy

[DoubleLung]

Would this motor work out?

 http://www.****.com/itm/Baldor-2-Hp-3Ph-motor-5-8-bore-208-230-460-1740rpm-U-5-/230859143530?pt=LH_DefaultDomain_0&hash=item35c046f96a

[gudspelr]

Sorry, for some reason I can't get the page to open... From the descriptors of the motor in the link, it sounds fine.  If you get a KBAC VFD, you can easily jump the rpm's to double for the max speed (maybe other brands do too, just not familiar with them).

Jeremy

[gables]

I too got a 3ph, Baldor, 2hp motor from the big auction site and only paid $100 for a brand new motor. The only issue I ran into was the mounting holes in the KMG base plate did not exactly match the motor bracket. I had to drill and tap 2 holes in my base plate to make it work. I also recommend the red link belts between motor and drive pulley. You will not regret going with the KBAC 27D VFD which I got from Wayne Coe. He also sells a VFD bracket and wiring kits if it is difficult for you to find flexible 4 wire cable and plastic glands. Go with a reputable motor company. I bought a cheaper second 2hp, 3ph motor for my disk sander from Surplus center. I installed a switch betweeen my variable speed controller and my two grinders. The cheaper, off brand motor runs rough at low speeds but the Baldor motor runs so sweet at any speed.

[WESTBROOK]

Doublelung, ya got 3ph power at your house?

Eric

[DoubleLung]

I don't have three phase power. I'm going to run a new dedicated 220 power line for the grinder. I planned on running 220 single phase to the VFD and three phase from it to the motor.

[WESTBROOK]

You got my curiosity up on this, I'm checking on VFD's VS Ph converters.

I knew a guy that just fed 1 Ph to a 3Ph motor, used a 4"angle grinder rig to get the 3p motor spinning, that created the 3rd leg and ran a 3ph Bridgeport...

Eric

[DoubleLung]

That is far beyond my overall understanding of the different phase motors. In the research I've done (and I know for certain with domestic pump motors) I can use a VFD to take single phase to a three phase motor.

Now it's just finding the right setup and time to get everything.

[WESTBROOK]

Yea, that was kind of a "hillbilly rig" and not a recomendation.

[WESTBROOK]

Well, I finally got to do a little lookin around. Yes you can run a 3ph motor with 1ph power. Hitatchi makes some small drives, 3hp and under you can get for less that $300. You just need a 1ph 4 wire (L1/L2/N/G).

Eric

[Ringneck]

I run a 3 HP, 3 phase motor with 1 phase power. Works great. I have an Allen-Bradley controller.

[manitou1]

The VFD converts 1ph to 3ph. That is the reason for requiring a 3 phase motor.

[WESTBROOK]

Not totaly, you can can VFD for 1ph motors.

[manitou1]

Yes, you are absolutely correct Westbrook, but if you purchase the VFD that converts it will require a 3PH motor and you won't have to do anything else, such as wire your shop for 3PH. It converts your single phase to 3 phase at the VFD. I was just trying to clear it up for an above poster to relieve their concerns about converting to 3PH in the shop... it is already done at the VFD, if it so states.  Just trying to help out.  You are correct that some VFD's don't convert to 3PH and it wouldn't be an issue then.  Hope it helps clarify things a bit.  Merry Christmas to all.
The KMG is a good one, by the way.  I use one in my shop with the VFD and a 2hp Leeson motor...it works great. The instructions for wiring the VFD are simple and easy to follow.