Harrison conversion to single phase

[Doddy]

My bad - 1C1/1C2 are the relays shown at the bottom of the schematic?

Then use two pairs of the 1c1/1c2 contacts to provide the change-over for the start coil, and the remaining contact for both 1c1 and 1c2 wired in parallel to provide the live supply to the motor run coil.

[Richard]

My bad - 1C1/1C2 are the relays shown at the bottom of the schematic?

Then use two pairs of the 1c1/1c2 contacts to provide the change-over for the start coil, and the remaining contact for both 1c1 and 1c2 wired in parallel to provide the live supply to the motor run coil.

Yes, 1c1 and 1c2 are the fwd/rev contactors operated by microswitches which are in turn operated by the motor control lever on the carriage. See bottom of schematic. Obviously they are never both closed!

You're right, I can use the third pair of contacts to switch the run coil on/off, which I haven't shown in my sketch.

Cheers!

[Richard]

Yes, 1c1 and 1c2 are the fwd/rev contactors operated by microswitches which are in turn operated by the motor control lever on the carriage. See bottom of schematic. Obviously they are never both closed!

You're right, I can use the third pair of contacts to switch the run coil on/off, which I haven't shown in my sketch.

Cheers!

Updated.

[magicniner]

I have a nice Harrison M300 lathe, which I have fitted a single phase motor to.

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?

[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.