Harrison conversion to single phase

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

I'd like to use all the exisiting switchgear, brake, fwd/rev lever etc.

Looking at the schematics, the contactor coils appear to run from 110v which is derived from a small transformer. This transformer has different input taps but not one for 240v, so if I replace the transformer with a 240 to 110, I should be able to use the exisiting switchgear with the single phase motor?

I haven't look at motor reversing in detail yet, but I am assuming this will need some re-wiring of the fwd/rev contactors.

Attachment 24908

Anyone else done this?

Cheers!

Without spending too much time on the schematic - yeah, looks to be picking a supply off two phases and transforming this to 110V (if the markings on the schematic are to be believed - no reason not to). So, yeah, get a 220-110V transformer of sufficient rating - it'll be right.

Reversing a single-phase motor is a case of reversing the starter windings. The usual three-position motor switches (On-Off-Reverse) provide the necessary switchgear.

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Originally Posted by Doddy

Without spending too much time on the schematic - yeah, looks to be picking a supply off two phases and transforming this to 110V (if the markings on the schematic are to be believed - no reason not to). So, yeah, get a 220-110V transformer of sufficient rating - it'll be right.

Reversing a single-phase motor is a case of reversing the starter windings. The usual three-position motor switches (On-Off-Reverse) provide the necessary switchgear.

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So this is what I think I need to reverse the single phase with the two contactors I have in the machine:Attachment 24924


I took the lamp off, built like it's designed to survive a direct nuclear strike! Massive cast box with a 415v to 50v transformer, 4 fuses and isolator.

I'm sure I can replace with something simpler...

Attachment 24925

The schematic - yup, though I'd be interested in the 1c1/1c2 arrangement - these are contactors?, what actuates these? a mechanical forward/stop/reverse switch? in which case this can be re-used - which is what I think you're after?

The other thing is to look to see if you can only energise the start coil whilst the run coil is energised - again, can be done with the 1c1/1c2 arrangement, depending on it's behaviour.

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.

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Originally Posted by 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.

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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!

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Originally Posted by 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!

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Updated.

Attachment 24926

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Originally Posted by Richard

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

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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?

Quote:

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Originally Posted by Richard

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

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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?

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Originally Posted by magicniner

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?

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

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