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I am a electrical technician but in school I dealt with mostly DC (electronics) stuff and programming and now at my work we do mostly 3 phase motors so I would like a better understanding of some stuff that I do.

Usually when I connect a 3-phase motor it has six leads and you can connect it in a star or a delta config.

So I was connecting a motor at home and it was a 3 wire, 3-phase motor so I googled and it says the motor is already connected in a star configuration since it is a D/Y 220V/380V motor.

So now I want to know when connected to a 380 V power supply and in star configuration, would it be the same as just using a one phase motor?

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  • \$\begingroup\$ No it is definitely still a three-phase motor. \$\endgroup\$
    – user57037
    Commented Aug 21, 2022 at 18:18

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... and it says the motor is already connected in a star configuration since it is a D/Y 220V/380V motor.

You can't assume that. Add a nicely cropped, in-focus photo of the rating plate and we can assist. If there is access to the internal terminals post a photo of that too.

So now I want to know when connected to a 380 V power supply and in star configuration, would it be the same as just using a one phase motor?

No. A three-phase motor uses phase rotation to give direction of turn. A single phase motor would start either clockwise or anti-clockwise - if it started at all. To give direction a second winding is required with a series capacitor to introduce a phase lead in the current. The small offset in phase is enough to guarantee that it will start in the intended direction.

It is possible to add a capacitor to a three-phase motor to get this effect but it might not be as good as a properly designed single-phase, capacitor start motor.

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