ironhoarder
Cast Iron
- Joined
- Oct 9, 2005
- Location
- Waterford, VA USA
I have a Brown and Sharpe 618 surface grinder and a number 1 universal grinder.
I'm trying to work out 3 phase power to these machines.
My original plan was to make a big rotary converter (I already have a 10 hp motor and the contactors and the caps). Of course, the 618 is wired for 440v and I'd have to reconfigure for 220. Don't know about the universal grinder, but I imagine it is 440.
Now- I may have an opportunity to get a 20hp VFD. I initially was thinking I could simply use it in place of the RPC- have it generate my 3 phase (it can put out 440) and keep the starting circuits intact on the machines.
But I've read that VFDs are not happy when they are putting out voltage and their load changes. They like to be hooked to a motor constantly.
Now, I could configure a drum switch to go between the 2 machines and bypass the mag starter circuitry. However, lets say I hooked up the main 2 motors (spindle and hyd pump) on the 618, there is a 3rd motor for the head raise/lower and that is used intermittently.
On the universal grinder, you would want to control the spindle and grinder motors separately. And I'd want to simply use the existing mag starter- so this would be bad.
It sounds like this is just a bad idea for these machines. What do you think?
I'm trying to work out 3 phase power to these machines.
My original plan was to make a big rotary converter (I already have a 10 hp motor and the contactors and the caps). Of course, the 618 is wired for 440v and I'd have to reconfigure for 220. Don't know about the universal grinder, but I imagine it is 440.
Now- I may have an opportunity to get a 20hp VFD. I initially was thinking I could simply use it in place of the RPC- have it generate my 3 phase (it can put out 440) and keep the starting circuits intact on the machines.
But I've read that VFDs are not happy when they are putting out voltage and their load changes. They like to be hooked to a motor constantly.
Now, I could configure a drum switch to go between the 2 machines and bypass the mag starter circuitry. However, lets say I hooked up the main 2 motors (spindle and hyd pump) on the 618, there is a 3rd motor for the head raise/lower and that is used intermittently.
On the universal grinder, you would want to control the spindle and grinder motors separately. And I'd want to simply use the existing mag starter- so this would be bad.
It sounds like this is just a bad idea for these machines. What do you think?