Building a grinder question

IFLY4U

IFLY4U

Joined
Aug 25, 2006
Messages
13
I am collecting items for a home made grinder and ran across a Leeson 2hp, 3 phase motor that is new for $50. Would this motor be suitable for a grinder? Would I be better off buying a Coote Grinder for $450 and hook this motor to it instead of using scrap material to make a home made one?
 
It will be fine if you have three phase power,or a three phase converter.It will loose a bit of power if you use a converter. Might be best to stick with a 220V single phase.
 
If you get the motor for $50, that leaves you some $$ for a Variable Frequency Drive to run it off of single phase power. Look at the ACTech controllers. I have one and it's been great. You'll also get variable speed out of the deal. They're only a NEMA-1 enclosure, so you'll need to put it in a sealed box to keep the dust out, but that's not too hard. I just cracked open the outside junction box I used to change a setting the other day and there wasn't a spec of dust inside. Don't believe all the hype about "NEEDING" a more expensive NEMA-4 unit.

-d
 
I have found 2 hp three-phase (220v) is more than sufficient power for a 2-inch wide belt machine.

When shopping for a a variable frequency drive, you may find one that specifically states it's for single-phase input. If you get one of these, a 2 hp rating is sufficient. If you get a drive that specifies three-phase input, it will work too (these tend to be cheaper and more plentiful), but you will have to get one rated for 3 hp or better because you're loosing one of the three 'legs' of input power (you will be hooking your single-phase power to two of the three input terminals provided and the drive will generate the third leg for you at output, but you're still missing about 1/3 the input power.) My experience is that a 3 hp three-phase input/three-phase output drive running with 220 single-phase input is sufficient to drive a 2 hp three phase motor without substantial power loss. (A 5 hp drive would theoretically be better, but those are usually quite a bit more expensive.)
Yes, you can run a smaller motor on a bigger drive, but not the other way around. So if you come across a 10 hp drive really cheap (assuming it isn't broken) go for it.
 
You can get a brand new 2 HP 3 Phase for $175 - this is the lowest price
from Grainger, for a huuuge Biz account. So if you can score one for $50,
go for it.

Make sure it has the mounts your grinder will require. Bader-like designs requires BOTH the face and base mount. KMG-like - only base.

Also, if you go for Bader-like design, make sure the shaft is at least 2 1/8
long, has a standard key-way and is beefy nuff: 3/4 or 7/8"

Another thing to check for: motor must be "Inverter" rated. Has to do with
higher level of electrical insulation in the windings.

And lastly: the motor should be TEFC - about the only acceptable type for a
grinder. TENV are never continuous duty in this HP range.

About VFD controllers: the KBAC-27D NEMA4 (wash-down safe) is the golden standart. You should be able to score one for $300-$312. NEMA-1 (open) are, if you get luckly, $250. A no brainer, IMO :) - go for KBAC-27D
 
I switched over to the KBAC also.... I used some that were not a NEMA4 enclosure and worked fine since I have them covered with an air flow... but, when the military moved me to Fort Bragg, nc from Ft Campbell.... the just threw all kinds of metal dust and so forth and did not do a good job packing.. so hence... two controllers bit the dust so I decided to go with the KBAC...

Make sure it is a NEMA 4 enclosure.... it is well worth the extra money...... nothing worse than when the grinder dies....
 
You must log in or register to reply here.
Back
Top