Hi all
I have a 1940s steel dial hardinge TM mill with a 230v-only, 2 speed 3ph motor. I hooked it up directly to a 220V single phase input VFD(Yaskawa GPD-205) using the high speed wiring (leads 4,5 and 6 to VFD, 1-2-3 tied together),and I have everything up and running.
I've noticed the motor isn't perfectly happy. The FLA for the high speed should be 2.4amps, but the VFD shows around 3amps when idling at 60hz. It rises during a cut - minimally during small to medium cuts, but up to 8 amps for heavier cuts - and the VFD overload fault happens frequently of I keep going. If I try to go above 60hz, the motor will speed up but the amp draw also rises. At 80hz, it draws around 4.5 - 5amps at idle. Above 80hz, the motor doesn't like it at all, and the speed actually starts to drop off.
I've played around with the belt tension, but it doesn't seem to make much difference. The jackshaft in the base was cocked a little, which I corrected and did see a small improvement, but only to the numbers I gave above.
With the belts off, the bearings in the motor, jackshaft and spindle all felt quite smooth and there's no real bearing noise.
I have two thoughts:
1) the motor is on its way out. It came from a medical device / prosthetics lab, and was covered in a thick layer of plaster of Paris dust when I got it. I'm wondering if that schmoo has somehow damaged the motors innards....
2) the VFD needs some more adjustment. I've looked through the manual, but not sure how to tune it any better than I have it now. The V/Hz ratio can be adjusted, but I've no idea where to start with that, or if that's even necessary.
Hoping there's a somewhat simple answer to this - the mill is otherwise ready to put to work!
Thanks in advance for any suggestions,
Lee
Sent from my SM-N960U using Tapatalk
I have a 1940s steel dial hardinge TM mill with a 230v-only, 2 speed 3ph motor. I hooked it up directly to a 220V single phase input VFD(Yaskawa GPD-205) using the high speed wiring (leads 4,5 and 6 to VFD, 1-2-3 tied together),and I have everything up and running.
I've noticed the motor isn't perfectly happy. The FLA for the high speed should be 2.4amps, but the VFD shows around 3amps when idling at 60hz. It rises during a cut - minimally during small to medium cuts, but up to 8 amps for heavier cuts - and the VFD overload fault happens frequently of I keep going. If I try to go above 60hz, the motor will speed up but the amp draw also rises. At 80hz, it draws around 4.5 - 5amps at idle. Above 80hz, the motor doesn't like it at all, and the speed actually starts to drop off.
I've played around with the belt tension, but it doesn't seem to make much difference. The jackshaft in the base was cocked a little, which I corrected and did see a small improvement, but only to the numbers I gave above.
With the belts off, the bearings in the motor, jackshaft and spindle all felt quite smooth and there's no real bearing noise.
I have two thoughts:
1) the motor is on its way out. It came from a medical device / prosthetics lab, and was covered in a thick layer of plaster of Paris dust when I got it. I'm wondering if that schmoo has somehow damaged the motors innards....
2) the VFD needs some more adjustment. I've looked through the manual, but not sure how to tune it any better than I have it now. The V/Hz ratio can be adjusted, but I've no idea where to start with that, or if that's even necessary.
Hoping there's a somewhat simple answer to this - the mill is otherwise ready to put to work!
Thanks in advance for any suggestions,
Lee
Sent from my SM-N960U using Tapatalk