Line voltage question, need help with answer

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twinbeams

Member
Location
Oregon
I recently took a quiz and this question was ask and I am running in circles trying to find the real answer. The question is: Line voltage in a three phase wye-connected A-C winding is equal to phase voltage times_________. I say it is three times. Can someone confirm this.

Choices were: 2, 3, 1.41, or 1.732.

Thank you,
Ron
 

hurk27

Senior Member
Re: Line voltage question, need help with answer

Here's a hint Three phase to root (xo) inbetween all three phase's (the square root of 3)=

[ September 09, 2003, 01:16 AM: Message edited by: hurk27 ]
 

Ed MacLaren

Senior Member
Re: Line voltage question, need help with answer

Twinbeams, Have a look at this sketch, perhaps it will help.

3ph1.gif


Ed
 

ron

Senior Member
Re: Line voltage question, need help with answer

You can try Ed's easy method of thinking about it, or you can open a physics book a attempt to understand adding vectors.
I vote for Ed's method.
Nice Job Ed.
 
Re: Line voltage question, need help with answer

Thanks Ed,

As long as I have been working around electric, I have never heard it explained this simple and direct. Yet very accurately!!!!!
 

big john

Senior Member
Location
Portland, ME
Re: Line voltage question, need help with answer

Not to negate Ed's beautiful diagrams, but you can reverse engineer this, as well. A wye-connected transformer might be 277 to ground, 480 phase-to-phase.
What's 480 divided by 277?

-John
 

iwire

Moderator
Staff member
Location
Massachusetts
Re: Line voltage question, need help with answer

Ed, I wish you had been my trade school teacher, while the man I had was a great guy, you seem to be a great teacher. :)

Plus I like how you would not speak to those without the code book. :D

Why show up with out the tools you need?

Sincerely, Bob
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Re: Line voltage question, need help with answer

Big John, why would you want to walk that far to show the same vectors. :roll:

Roger
 
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