motor question

Sean Cochran

Sean Cochran

Well-Known Member
Ok, Ive got a motor for free at work. It was on a hose cutter, but I know squat about electronics. It is a Baldor 3 hp, 3 phase. Since Im building a new KMG clone I was thinking I could use it to make a variable speed, problem is I know I need a VFD but other than that Im lost.
Is this a good option?

Thanks

Sean
 
Sean,

I've got a 3hp 3phase grizzly on my KMG. My motor control is a TecoFm50 which I had hardwired. Decided I needed a disk grinder so I got a 1.5hp grizzly and wired a dryer outlet on the VFD and dryer plugs on the motors. Good to go now ! Eventually I want to get a horizontal grinder for profiling and again not a problem. 3Phase motor and dryer plug and I'm set. 3 Variable Speed Reversable grinders run from a single 220 circuit and VFD.

The vfd is $185 from www.factorymation.com

This is not a nema 4 enclosure so I built a wooden box from scrap and mounted automotive air filters to it and put a thin plexi-glass cover on the front. I opened it when wiring the outlet and NO dust inside whatsoever.

I did tons of research before going this route but I'm very happy that I did.

-Josh
 
If you had to buy the motor I'd say maybe but being that it's free, I'd say go for it. Three phase motors are not as expensive as single phase motors but a new new 3hp motor constant speed single phase motor is not going to be cheap. One that was variable speed would be outragious. Even used units can put a dent in the pocketbook.

Doug Lester
 
Sean Cochran said:
OK, Ive got a motor for free at work. It was on a hose cutter, but I know squat about electronics. It is a Baldor 3 hp, 3 phase. Since I'm building a new KMG clone I was thinking I could use it to make a variable speed, problem is I know I need a VFD but other than that I'm lost.
Is this a good option?

Thanks

Sean
Click to expand...

Sean,

Two questions:

1) Is the motor totally enclosed? Look on the data plate for enclosure type(ENCL), it should have TEFC on the data plate if your going to use it for grinding.

2) What is the Voltage of the motor? Again check the data plate for VOLTS. Most 3 Phase motors are dual voltage, i.e. 240/480 VAC. Your home will normally have no higher voltage available than 240 VAC.

If your free motor matches the two above requirements, get a VFD and follow the instruction manual to wire it up. A new VFD will usually let you call the free tech support line for additional help. Or you could post here again once you've got more information to work with.

Mike
 
Thanks for the help guys.

It is TEFC and 240/480. Seeing that Im working on a somewhat tight budget I am pretty happy with the price on the motor. Any suggestions on the VFD?

Sean
 
Check out the link Josh included in his post. You need the model FM50-203-C from the website linked for a 3HP motor. I did a quick scan of the manual, and you'll need a 240 VAC 2 pole 30Amp circuit for main power. Your clothes dryer has this same size breaker in the main panel as a visual reference.
 
Thanks so much guys.
Josh I dont know how I missed the link when I first read your post, thanks.
Mike, I left a 30 amp 2 pole when I wired my shop (I can handle wiring up to the outlet, its when it comes to the motors that Im lost).
I really appreciate the help fellas, Im going to try to order the VFD soon, but I still have some machine work on the grinder body.
Im sure I will need alot more help when I actually start hooking it up, so stay tuned:)

Sean
 
Sean,
If you can wire the main 220v to the drive then your pretty much golden. The rest of the wiring is really a cinch. I'd be happy to get some pics of my stuff and label where the wires go. Don't be intimidated by wiring the drive to the motor if you'ld feel better I'd be happy to walk you through it on the phone. Assuming that you got the same drive that I got anyway.

-Josh
 
Josh Dabney said:
Sean,
If you can wire the main 220v to the drive then your pretty much golden. The rest of the wiring is really a cinch. I'd be happy to get some pics of my stuff and label where the wires go. Don't be intimidated by wiring the drive to the motor if you'ld feel better I'd be happy to walk you through it on the phone. Assuming that you got the same drive that I got anyway.

-Josh
Click to expand...

Careful what you offer, Josh;) Thanks, I may take you up on it. Im hoping this is one of those things that Im making harder than it really is.
I followed your link, and the price seems fair. Since you are using that with no problems Ill trust your judgement. Now if I could just get some time away from the pipe yard I could get the body of my grinder finished, man having to work a "real job" really is getting in the way of my knife addiction.:mad:

Sean
 
I'm no expert on electronics but I went with the TECO because I knew several others were using it without problems. And the price was right.

I haven't had any problems with it yet and it does exactly what it's supposed to.

Probably not the best reason to pick one VFD over another but I'm happy with the purchase.

Seriously a pic of the VFD with labels is all you'll need but the offer stands reguardless.

-Josh

-
 
Doug Lester said:
If you had to buy the motor I'd say maybe but being that it's free, I'd say go for it. Three phase motors are not as expensive as single phase motors but a new new 3hp motor constant speed single phase motor is not going to be cheap. One that was variable speed would be outragious. Even used units can put a dent in the pocketbook.

Doug Lester
Click to expand...

You are right on a 3 phase motor and VFD will cost about the same as a comparable single phase unit. You also get the benefit of variable speed quieter operation and a smoother running longer lasting machine, all in a more compact unit. I go with a 3 phase motor every time good find on the free one.
 
Sean....I'm building a KMG clone too,I was thinking of doing away with the bearing mounts,where the flange bearings are mounted,and mounting two pillow block bearings to the rear main support,any thoughts on this idea? Thanks, JCullen
 
jcullen said:
Sean....I'm building a KMG clone too,I was thinking of doing away with the bearing mounts,where the flange bearings are mounted,and mounting two pillow block bearings to the rear main support,any thoughts on this idea? Thanks, JCullen
Click to expand...

Im thinking of doing the same thing. I dont think it should make any difference in the operation of the grinder


Sean
 
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