Running 380V 3-phase motor on 230V 1-phase

[Robert Atkinson 2Participant @robertatkinson2]

Well I’m not going to respond to any more of Bob’s comments.

Robert

[Andrew SkinnerParticipant @andrewskinner94774]

Has anyone got a comment on my calculations, 26th June 13:11, about halfway down page 2?

They seem to indicate the motor requires 220V line voltage 3ph, not 400V. I’d like to know either way, and I’d say the OP would, too.

[Robert Atkinson 2Participant @robertatkinson2]

We do seem to have been a bit diverted from the original question…
The biggest issue is that the photo of a motor dataplate in the first post,  https://www.model-engineer.co.uk/forums/topic/running-380v-3-phase-motor-on-230v-1-phase/#post-851454
Is NOT off the motor in jimalm’s lathe. So we are all just guessing until we have sight of the ACTUAL motor dataplate.

I have spent some time looking at these 3 phase, 3 speed motors generally. They appear to have 3 sets of windings. Two are a Series Delta switchable to Parallel Star like a Dahlander two speed. The third set are wired Star. But I can’t figure out exactly / definitively how they are connected. I’ve found different motor diagrams and lathe switching diagrams but all of them are either lacking information or have inconsistencies For example a unlabelled connection or mismatched terminal designations.

Robert.

[Andrew SkinnerParticipant @andrewskinner94774]

The way I read the first post, the photo IS of the OP’s motor, but he’s found a photo (not shown) of a similar motor that states 380V.

[Robert Atkinson 2Participant @robertatkinson2]

My bad.

The motor does look to be very inefficient at any voltage or speed.
I’d be looking at a delta connected modern 4 pole motor a with a VFD to attain the  speed variation. If the user is more likely to need most power at lower speeds (cutting big bits of tough material) then a 6 pole would be better. You still get the higher speeds but torque would be reduces but OK for small parts or softer materials where yu want high speeds and sharp cutters.

Robert.

[Robert Atkinson 2Participant @robertatkinson2]

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