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!
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:
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:
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:
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.