# 5 wire 2 phase system

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#### jasons

##### Member
I am currently teaching an electrical apprentice
class to second year apprentices. The only question I have not yet been able to answer is, what is a 5 wire 2 phase system? Can someone give me some help? I have never seen anything even close. Article 220.22 in the 2003 code makes a reference to it.

#### rb

##### Member
Re: 5 wire 2 phase system

Jason,

Imagine two single phase center tap transformer secondaries connected in a "T" at the center taps with the junction of the center taps serving as the grounded conductor or fifth wire.

I heard somebody once say they had seen one in Texas. I never have seen one.

#### scott thompson

##### Senior Member
Re: 5 wire 2 phase system

Maybe the Schematics I have posted at ECN's Technical Reference section would be of help to you.
Although I did not include a 2 Phase 5 Wire setup, the 2 Phase 4 Wire setup is the one used to derive the 5 Wire system.

I will try embedding a link to the "Menu" of reference items, plus some Schematics of 2 Phase systems. If not successful, paste the link's URL into your browser's Location field.

Scott35.

http://electrical-contractor.net/ubb/Forum15/HTML/000064.html

Schematic 1:

Scott35 S.E.T.

#### jmc

##### Member
Re: 5 wire 2 phase system

I worked on two-phase, 1200 Hertz generators back in the 50's. The windings are arranged so that there are two sets of windings, 90 degrees out of phase, with a common conductor from the center connection point of the two sets of windings. The phase voltage is 1.41 times the voltage from the the center (common) to each phase. In Scott
Thompson's Figure #1, bring out a common from the center where the windings cross and u have a 5-wire 2-phase system. I haven't mastered diagrams on this site YET! But will try.

#### hurk27

##### Senior Member
Re: 5 wire 2 phase system

I had a contract one time to work on an old draw bridge about 20 years ago boy did I hit the books before that I never seen one

#### mikeames

##### Senior Member
Re: 5 wire 2 phase system

One of our old members "Benny" knew about these 2 phase systems used on some old farms. Interesting.

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