Grinder drive wheel size
- Thread starter Kev
- Start date
tkroenlein
Well-Known Member
Well, if you haven't procured a motor yet, I'd recommend a 1740 RPM motor with a 6" or 7" drive wheel, running the VFD on 2X.
If you do have the motor already, it looks like you'll need a 5" wheel to get sufficient top end speed.
If you do have the motor already, it looks like you'll need a 5" wheel to get sufficient top end speed.
EdCaffreyMS
"The Montana Bladesmith"
The two main grinders I use in my finish shop, both use 3hp motors, 3 phase/220V, 1740RPM.
One machine is used primarily with a 10" contact wheel, and that machine runs a 4" rubber covered drive wheel. The other runs a 6" aluminum drive wheel.
Both of these machines are connected to/run by the same KBAC 29D VFD/controller. The MOST I ever run the machine with the 6" drive wheel is about 50% on the VFD, and the machine with the 4" rubber covered drive wheel often runs at 100%. So, for me, IF I could, I would be running a 4" wheel on both machines.
Now the caveats/other things you need to consider. First among those is belt slippage. Although most don't consider it, a solid/non-covered drive wheel obviously allows for far more belt slip then the same wheel that is rubber covered. Diameter is also a factor in belt slippage..... the smaller the drive wheel diameter, the less contact with the belt it has, which increases belt slippage. As the diameter of a drive wheel increases, there is more surface area in contact with the back of the belt, USUALLY resulting in less belt slippage. I would love to have a 6" rubber covered drive wheel for my KMG TX. I've thrown more belts with it, then with any other grinder I've ever owned or used.
That's one of the down sides to having a ratcheting belt tension system on a grinder..... as belts are used, they heat up, and they stretch. Since a ratchet tension system doesn't provide for constant tension (a spring is under constant tension), unless the user remembers to check the belt tension OFTEN, belts slipping, and flying off the machine are fairly common.
All that being said, I think the best all around choice for a grinder using a VFD, is a 6" drive wheel, with a 1725-1800 RPM motor, with the VFD jumper set to 2X motor speed. This will give the widest range of speed choices, and using the slower motor will give you all the torque you need. (if you use the motor you mentioned, you will have torque issues, as in not enough torque (you will be able to slow the grinder down when grinding, by applying too much pressure).
I just wish somebody offered a quality rubber covered 6" drive wheel...... I'd have that on my KMG TX in a hot minute.
One machine is used primarily with a 10" contact wheel, and that machine runs a 4" rubber covered drive wheel. The other runs a 6" aluminum drive wheel.
Both of these machines are connected to/run by the same KBAC 29D VFD/controller. The MOST I ever run the machine with the 6" drive wheel is about 50% on the VFD, and the machine with the 4" rubber covered drive wheel often runs at 100%. So, for me, IF I could, I would be running a 4" wheel on both machines.
Now the caveats/other things you need to consider. First among those is belt slippage. Although most don't consider it, a solid/non-covered drive wheel obviously allows for far more belt slip then the same wheel that is rubber covered. Diameter is also a factor in belt slippage..... the smaller the drive wheel diameter, the less contact with the belt it has, which increases belt slippage. As the diameter of a drive wheel increases, there is more surface area in contact with the back of the belt, USUALLY resulting in less belt slippage. I would love to have a 6" rubber covered drive wheel for my KMG TX. I've thrown more belts with it, then with any other grinder I've ever owned or used.
That's one of the down sides to having a ratcheting belt tension system on a grinder..... as belts are used, they heat up, and they stretch. Since a ratchet tension system doesn't provide for constant tension (a spring is under constant tension), unless the user remembers to check the belt tension OFTEN, belts slipping, and flying off the machine are fairly common.
All that being said, I think the best all around choice for a grinder using a VFD, is a 6" drive wheel, with a 1725-1800 RPM motor, with the VFD jumper set to 2X motor speed. This will give the widest range of speed choices, and using the slower motor will give you all the torque you need. (if you use the motor you mentioned, you will have torque issues, as in not enough torque (you will be able to slow the grinder down when grinding, by applying too much pressure).
I just wish somebody offered a quality rubber covered 6" drive wheel...... I'd have that on my KMG TX in a hot minute.