Harrison conversion to single phase

[Richard]

I helped a friend to fit a VFD to his and convert the rest of the switch gear to 240, why on earth would you want to fit a motor providing "Lumpy Torque" to such a nice lathe?

I had a single phase 2.2kw motor handy...

Do you think I'll see the lumpy torque in the surface finish?

[magicniner]

I had a single phase 2.2kw motor handy...

Do you think I'll see the lumpy torque in the surface finish?

You'll have to wait and see, you don't have the rubber mounts normally associated with single phase machines, they help significantly in smoothing out the bumps in the torque output.
I noticed a significant improvement in surface finish when I converted my Myford Super 7 to 3 phase, I would never go back to single phase for a lathe or mill,
Regards,
Nick

[Richard]

You'll have to wait and see, you don't have the rubber mounts normally associated with single phase machines, they help significantly in smoothing out the bumps in the torque output.
I noticed a significant improvement in surface finish when I converted my Myford Super 7 to 3 phase, I would never go back to single phase for a lathe or mill,
Regards,
Nick

The motor is bolted to the the headstock but the drive is via belts and it's spinning a big old chuck so may not be too bad.

I'll face off some ali and see if there is any sign of uneven cut.


So when you fitted a VFD, I assume you delta the motor and wire the VFD direct to it? I read that VFD's like to be close to the motor and don't like contactors etc in the way.

Did you re-wire the fwd rev microswitches to operate the VFD or just add a control pendant/box for the VFD?

I would like to retain the fd rev lever and footbrake.

[magicniner]

Yes, motor Delta, wired my friend's 300 to use all the standard controls, just with a speed pot added, Fwd/Rev lever works as standard as does the foot brake.
He initially wired the motor Gamma (I named it after him) where the two ends of each winding were joined and one inverter phase was connected to each closed loop! :D

[Richard]

In the end I managed to get a rotary inverter which works great and was fairly cheap (1/3 new price). There is definatley less vibration but I didn't check surface finish with the single phase.

Nice to have original lamp and subs pump going, along with all the switchgear kept as standard.