## Outstanding explanation of single and 3 phase electrical power.

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JoeBallantyne
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Real name: Joe Ballantyne
Location: Redmond, WA

### Outstanding explanation of single and 3 phase electrical power.

I just saw this video on youtube when looking for information on rotary 3 phase converters, and it has the clearest explanation I have ever heard of both 3 phase and single phase power setups. I wish I had gotten an explanation like this in college. Explains standard US single phase setups as well as 3 phase wye and 3 phase delta and how they work. It also explains how 3 phase rotary phase converters work. (They make 3 phase delta.)

https://youtu.be/mUXLxK_zI24

Joe.
Emma Black
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Real name: Emma Black

### Re: Outstanding explanation of single and 3 phase electrical power.

This is great. I came across this exact video a while back when pondering getting a single or 3 phase lathe and then buying a 3 phase converter. I went with single in the end.

The split phase element is also interesting, we don't have that here for some reason, its just 230v at every socket.
3 phase here is also 120 degrees apart not 180 which gives 400v (230v*1.72) rather than 480v (240v*2)
Jerry Biehler
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Location: Beaverton, OR

### Re: Outstanding explanation of single and 3 phase electrical power.

120v (110v) in the US dates back to the old DC systems if I recall. So that's just what we have now. To change would be cost prohibitive. So one extra wire from the distribution transformer splits it to 240/120 center tapped.

Three phase here is 120 degrees apart just like everywhere else. The main 3 phase power we have is 240/120 high leg delta, where one output of the mains transformer has a center tap for 120, 240 or 480 delta, 480/277Y and 208/120Y. Y is probably the most common setup. 277v is most often used for lighting. There is 600v as well but outside of heavy industrial industries it is pretty rare.