Variable speed motor question...

Alain M-D

Alain M-D

Joined
Jan 20, 2002
Messages
237
I received my Coote Grinder a few day ago! I am verry happy !

Last Friday I bought a variable speed motor (General Electric, 90 v DC, 1hp, TEFC + control) and I wonder about his capacities... Once installed on my grinder it is relatively easy to stop, and very easy to stop when I slow down the speed. Is this normal?

(I tested with an other variable speed motor (only 1/3 hp) and I dont see a big difference than 1 HP...)

With a 1 hp motor, it is normal to be able to stop the contact wheel with moderate pression on the contact wheel ?

Thanks !

Alain M-D
 
Alain M-D, your controller should have several trim pots inside... min speed, max speed, torque, etc. While the grinder is running under a load, try slowly adjusting these, one at a time. Refer to instuction manual of your controller for specific adjustments.
 
A 1 HP motor is not very strong for heavy pressure while grinding. I would suggest that you reserve the slow speeds for finishing where the slower speed will do more good and run your heavy cuts at full speed.
 
I agree with George. My motor is 1 1/2 h.p. and I use it only for final finishing where I want better control and slower speeds.

Marcel
 
Alain-

I had the same problem when I first installed my var-speed. As mentioned, there are settings inside the controller that can be adjusted up.

When I did the adjustments my grinder power was a little more than doubled!

Do an on-line search for the controller manual and then read that through a couple times- it will show where the controls are and how to adjust them.

I have a 1.5 horse on my flat grinder and a 1.25 on my hollow grinder. I can still stop either with a LOT of grinding pressure. I think you need to get up into the 4 or 5 horse range before they will rip your arm off :)

Dave
 
Thanks all for your reply !

I bought the 1hp because the 1.5 was twice more expensive...
already that the 1hp is rather expensive...

I have 4 small pots in my controller, Vmax, Vmin, DelayUp, DelayDown, but I dont have "torque" ...

Should I exchange my controller for a model with torque adjustment ?

Alain M-D
 
Alain, try adjusting the pots that are in your controller. I don't think you will hurt anything, and the torque pot could be labled by a different name in that model of controller.

It's worth a try.
 
Alain M-D; you didn't state the rpm of your motor. Higher speed motors have less torque than low speed motors. Some controllers are not set up for torque applications. If the controller is not factory new the trim pots could be totally out of adjustment. Some controllers use compensation resistors to adapt different horsepower motors to the same model of controller,each horsepower voltage combination requires a different resistor. I used a 3/4 hp for a few days on my grinder. Normally I have a 11/2 on it. Worked better than I thought it would. But, I think one and a half or two horse motors are a better way to go. mike
 
Thank everyone!

Finally I exchanged my controller drive for another model
(with torque one and IR compensation adjustment) and
WOW !! My motor work verry well ! I am not able to stop the
motor now !!

Alain M-D
 
Johnny and Mike,

I have a VS motor for a disc grinder that I am adjusting right now. I have adjusted each trimpot, but never while the machine was running. I adjust, turn on, turn off, re-adjust, etc. How do I adjust withthe motor running safely? Also, when you say "under load" what exactly do you mean?

Thanks,

John
 
John, I have my variable speed motors on my 2 x72 belt grinders. To adjust my trim pots, I put a belt on, turn on the machine and run up the speed to about 50%. With the load on the machine, when you make the trim pot adjustments, you can actually see, and hear, the changes as the motor will speed up, or slow down, depending on the particular adjustment you happening to be making.

I've been able to fine tune my grinders this way, for maximum performance.

Hope it works for you.
 
Thanks Johnny,

Do you do this with a non-metallic screwdriver/tool. It sounds dangerous, electrically.

John
 
John, get a set of tuning screwdrivers, etc., from Radio Shack. They are all non conductive, and very inexpensive.
The set I have is #64-2220a Archer, 5-piece TV Alignment Tool Kit. It cost me $2.99, AND, it comes with a free pocket protector,ahhhhhhhh;)
 
Hey Guys..

I was just talking with Rick Frigault about this very thing the other night..

Seems he's installed a variable speed AC motor onto several of his machines, with a Leeson Speedmaster(I think thats what the name is) ...

It can also be programed to do different things...
You would have to change the motor to an AC 3 phase though..

By the way it sounded,, you don't lose any torque when you slow down the motor, even at a crawl it keeps the same torque...

The entire setup including motor would be cheaper than converting over to DC or than buying a variable speed DC grinder..Cost was roughly 500CDN...

ttyle

Eric...
 
most of those things can be used as either 110 or 220.....it will work way better with 220v.
I am talking about the dc motor in the original post.
 
You must log in or register to reply here.
Back
Top