hunter27
Pete
- Messages
- 835
- Location
- Lancashire UK
Sorry Following on from my VFD/potentiometer thread I'm beginning to wonder if it could be the motor at fault or both.
I have been running a Boxford 3 phase lathe using a VFD on single phase for around 2 years now. The remote speed pot stopped working on my 20years +VFD and the lathe would only run at aprox 1/3rd speed.
The very helpful chap at IMO inverters suggested I check the motor which I did as best as I could,it's 3 phase in delta I disconnected all the wires and identified the phase loops, they all gave the same resistance reading, I checked every phase to earth with a multimeter and between the phases and it all seemed to check out okay.
I then tried my sons Chinese VFD on it and although the speed picked up a little it's still nowhere near what it was or should be, also if I set the pulleys to the fastest setting the lathe will not start as the motor just buzzes. There is no great resistance turning the chuck by hand.
I don't thing I should be able to stop a 4"chuck running at around 700RPM using just my hands on a 3/4HP motor. That was on the second fastest pulley options.
I don't want to replace the wrong bit what do you think?
Pete
I have been running a Boxford 3 phase lathe using a VFD on single phase for around 2 years now. The remote speed pot stopped working on my 20years +VFD and the lathe would only run at aprox 1/3rd speed.
The very helpful chap at IMO inverters suggested I check the motor which I did as best as I could,it's 3 phase in delta I disconnected all the wires and identified the phase loops, they all gave the same resistance reading, I checked every phase to earth with a multimeter and between the phases and it all seemed to check out okay.
I then tried my sons Chinese VFD on it and although the speed picked up a little it's still nowhere near what it was or should be, also if I set the pulleys to the fastest setting the lathe will not start as the motor just buzzes. There is no great resistance turning the chuck by hand.
I don't thing I should be able to stop a 4"chuck running at around 700RPM using just my hands on a 3/4HP motor. That was on the second fastest pulley options.
I don't want to replace the wrong bit what do you think?
Pete