Grinder drive motor

B

Brad Lilly

Moderator and Awards Boss
I'm here again asking for advice. I have my hands on a 110/220v 3hp sealed motor. I was thinking about mounting it on my grinder (direct drive). The thing is a tank it has an 1 1/8" output shaft and grease fittings front and back. It has been rebuilt 20 years ago and stored since. I gave it a test run and it runs like a top however there is one big drawback it runs at 3450RPM. Now I'm concerned that it will be too fast and wont work, I do have a guy who will build me a custom wheel 3" in diameter to slow her down a bit. Here she is

Any advice would be appreciated.
 
You could use step pulleys & link belt to make it adjustable and slow it down, of course that won't be direct drive?

Wayne Coe here at KD's with Moe the shop dog would be the one to ask if you could get a variable speed drive control for that breast?

Have fun!

Laurence

www.rhinoknives.com
 
I'll be glad to help. I'm assuming that is a single phase motor. If so you can't use a VFD with it. Sooner or later you are going to want a veriable speed grinder so I suggest that you contact me and get the motor and VFD that you need. Save that monster for another purpose or sell it to help finance your veriable speed equipment.

If you are going to set it up as a direct drive the 3450 rpm is ok. We talk about rpm all of the time, what you are really interested in is feet per second of belt travel and that can be controlled somewhat by the size of the drive wheel.
 
You could use step pulleys & link belt to make it adjustable and slow it down
Click to expand...
It could be done but that's a bunch of frigging that I would like to avoid.

Thanks Wayne you are right variable speed is what I want. I'm not sure my knife making can justify the money right now.
 
Brad,
Its not as much frigging as you think!

I use a two step pulley & link belt system for a couple of years till I had the cash to get a Variable 1 1/2hp Hardcore products grinder If you are short on money? It's the least expensive way to get grinding with a adjustable speed rig.

Laurence

www.rhinoknives.com
 
dont need anything custom. here is a 2 3/4" pulley for this motor. http://www.surpluscenter.com/item.asp?item=1-BK27-F&catname=powerTrans and yes, you read the price correctly, $7. they also have keyed shafting, pillow block bearings, and belts. this link has many multistep pulleys. http://stores.ebay.com/Redshellers-Store?_trksid=p2047675.l2563 the only issue is it will be kinda klutzy to change speeds. If you want the high speed, you can also find step down shaft adapters so you can keep direct drive. again, will be klutzy because you will have to mod how the motor mounts.
looks like grinder speed will take the place of "Forged vs. Stock Removal." extensive tests at a local belt grinder maker has shown that while high speeds(greater than 2000 rpm motor speed) work great for coarse belts (80 grit or less), finer grit belts (120 grit and higher) have a usable life of seconds at these speeds.
 
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