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Can you run a single phase motor, with run capacitor, rated 220V with a 3 phase supply (220V delta) and without the run capacitor. I mean supplying each wires coming out of the motor with 3 phase 220V instead of using a single phase 220V plus the run capacitor. Since you can start a 3 phase motor with a single phase supply by adding a capacitor can you do it the other way around?

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  • \$\begingroup\$ As asked - NO! - when you say "all 3 lines" you are presumably referring to the main winding plus start winding connections. \$\endgroup\$
    – Russell McMahon
    Apr 6, 2022 at 11:16
  • \$\begingroup\$ As the other McMahon said: NO. If you connect the 2 windings in series with the capacitor across the start winding, it will run, but you might burn the motor out. The start winding will probably be rated at less current, and/or maybe a different voltage. If it is a 2 phase motor like ceiling fan motors with 2 identical windings, the windings will have about 268.7V (380/√2) each across them. A bit high for the motor and the capacitor. Definitely DO NOT connect the 3 wires to the 3 Phases or 2 phases & neutral as the phasing is wrong 120 deg. instead of 90, and voltage ph-ph is 380v. \$\endgroup\$ Jul 9, 2022 at 6:34

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Yes you can run the 1-phase, 220V motor from a line-line connection on a 3-phase, 220V delta. You would still need the start capacitor. Also, make sure case grounding is properly maintained as applicable (detailed wiring drawing will show).

If you are asking if you can supply the start capacitor leg with one of the other line-line delta voltages (for out-of-phase voltage) IN PLACE of the start capacitor then you will have to ask the manufacturer. Using another line-line would provide a full \$±120°\$ shift whereas using the start capacitor and the same line-line voltage would be something less (e.g. \$-90°<\theta<+90°\$).

Do you have a detailed wiring/winding drawing for the motor?

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  • \$\begingroup\$ I mean use 3 lines of 3 phase supply instead of just using any two of the three lines plus the capacitor. there isn't actually a motor i was just wondering if a single phase motor with a run capacitor can be supplied with 3 phase supply without the capacitor instead. \$\endgroup\$
    – Civi
    Mar 25, 2022 at 4:19

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