Bukes wrote: ↑Mon, 08 Nov 2021, 08:01Can you achieve a similar outcome by wiring an AC motor in delta but delivering star voltage?
Yes. But instead of 2:1 or 4:1 you get 1.73:1.
Perhaps using step up transformers?
A transformer is totally impractical in a vehicle. It would have to be a relatively low frequency type, which means it would likely weigh more than the car. It would also have to handle a wide frequency range, which is not practical either.
So if I have a 415v delta / 690v star motor, could I wire it in delta, but deliver 690v to it and increase the current about 1.65 times?
Yes, but generating 690 VAC phase to phase requires something over 1000 VDC (from poor memory and a quick search). So really you're better off finding a motor that is designed for a low voltage in star, then rewiring it for delta. For example,
Weber and Coulomb's MX-5 motor is wound for 400 V star and 230 V delta (both phase to phase; quoting middle of the range values). Those figures rise to 460 V and 265 V at 60 Hz. But that usually means a custom motor, or at least buying one off a catalogue. You are unlikely to find a surplus motor wound like that. I think it's because of the fear of circulating currents in delta connection; these currents don't happen in star connection.
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