This one is not rocket science but some of you may be interested to see how I did it.
It's an 8" GMF 3P grinder that was given to me as it was going to be thrown into a skip.
It looked like it had been used to grind something corrosive as the grinder base and one of the wheel guards was very rusty. Sorry no photos of this.
As usual the motor had to be converted to ∆.
Finding the Y common point was the trickiest one I have done so far but once that was done, apart from a tight space to operate in inside the motor the conversion itself was straightforward.
The next thing was to do a rust removal and repainting of the base.
Then I replaced the 3P simple rotary on/off switch with a 1P NVS (fat yellow switch at the bottom of picture) and sorted out the motor inside the grinder base.
I made up a connection/terminal block (the bits with the brass strips on it) and drilled and trapped threads into the base to hold the terminal block in place. The connections are then made in ∆ but it's also very easy to turn it back into a Y connected motor if needed.
The grinder base sits on a sheet of 8mm plate to which is welded an 60 mm length of 1" SSS that neatly slides inside the blue SHS support
At the back of the base I added two extra cable glands.
1Pi - is the single phase from the mains to the the NVS.
1Po - is the single phase to the VFD
3Pi - is the 3P from the VFD back to the motor
The latter two cables connect up to a VFD through the section of blue 30 x 2.5 mm SHS.
Here's what it looks like from the front.
The VFD is a $70 cheapie that Joe Hovel organised for a few members a while back.
I have it set to run up to 60Hz which it seems to do very smoothly.
I now need to pull it apart and paint all the bare steel.
Then I need to derust and tidy up the supports.
I'm hoping to mount a CBN wheel on one side - don't know about the other side yet.
It's an 8" GMF 3P grinder that was given to me as it was going to be thrown into a skip.
It looked like it had been used to grind something corrosive as the grinder base and one of the wheel guards was very rusty. Sorry no photos of this.
As usual the motor had to be converted to ∆.
Finding the Y common point was the trickiest one I have done so far but once that was done, apart from a tight space to operate in inside the motor the conversion itself was straightforward.
The next thing was to do a rust removal and repainting of the base.
Then I replaced the 3P simple rotary on/off switch with a 1P NVS (fat yellow switch at the bottom of picture) and sorted out the motor inside the grinder base.
I made up a connection/terminal block (the bits with the brass strips on it) and drilled and trapped threads into the base to hold the terminal block in place. The connections are then made in ∆ but it's also very easy to turn it back into a Y connected motor if needed.
The grinder base sits on a sheet of 8mm plate to which is welded an 60 mm length of 1" SSS that neatly slides inside the blue SHS support
At the back of the base I added two extra cable glands.
1Pi - is the single phase from the mains to the the NVS.
1Po - is the single phase to the VFD
3Pi - is the 3P from the VFD back to the motor
The latter two cables connect up to a VFD through the section of blue 30 x 2.5 mm SHS.
Here's what it looks like from the front.
The VFD is a $70 cheapie that Joe Hovel organised for a few members a while back.
I have it set to run up to 60Hz which it seems to do very smoothly.
I now need to pull it apart and paint all the bare steel.
Then I need to derust and tidy up the supports.
I'm hoping to mount a CBN wheel on one side - don't know about the other side yet.
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