How does 3 phase power operate single loads

power supplythree phase

I am wondering how 3 phase power is used to power, say for example, light bulbs? If I have 3 phase power coming into my house, how are the 3 phase combines to enter the one prong of an electrical outlet and then exit the other prong? How is 3 phase power concentrated into 1 line? Or is it?

I am trying to understand what happens, which is why there are a few (maybe overly broad) questions. And then there are electronic devices that contain converters to go from AC to DC (for example our baby monitor).

Any explanation is greatly appreciated!

Best Answer

3-phase can take two forms. The general high voltage transfer lines are called "3 Phase Delta" configuration. In this arrangement the power forms a triangle. It's easiest to understand it from the PoV of a transformer's windings:

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The other form, which is used for local distribution amongst properties, is called "3 Phase Star". The triangle is kind of turned inside out and it forms a star:

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A normal household would get N and one of L1, L2 or L3 (in the US and some other countries you get "split phase" where one line signal is divided into two).

A special transformer which has both types of winding arrangements in it converts the delta to star format:

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The voltage between Lx and N is the normal "line" voltage for your country (240V in the UK, 110V in the US, etc).

The voltage between two Lx lines is the "3 phase" voltage for your country - 415 in the UK, 203V in the US.

So a normal light bulb would be connected between, say, L1 and N.

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