[ale] Not so evil empire

[krwatson at cc.gatech.edu]

> -----Original Message-----
> From: ale-bounces at ale.org [mailto:ale-bounces at ale.org] On Behalf Of JK
> Sent: Thursday, July 16, 2009 10:37
> To: Atlanta Linux Enthusiasts - Yes! We run Linux!
> Subject: Re: [ale] Not so evil empire
> 
> Idle questions/comments below:
> 
> Robert Reese wrote:
> > Hello Richard,
> >
> > So, specifically, Richard, if you are at the end of the line, ask your
> power company if it
> > terminates the line at or near your home, and if so ask the workers what
> it would take to offer
> > you another phase.  Better yet, find out how much it would cost to go
> three-phase which would be
> > easy if you were at the termination of all three phases on that end-of-
> the-line. It might be
> > worth your while to go three-phase.
> 
> 
> Am I correct in believing that a 220AC outlet, such as the one I have in
> my house
> for the hot tub, requires at least 2 phases?
> 
> 

Not really. The power to your house comes from a center tapped transformer. From the center tap to either leg is 120VAC. For large appliances like ovens and hot tubs they connect across both legs to get 240VAC.

People commonly call the two 120VAC legs in their breaker boxes "phases" but in reality they are both in phase with each other.

In a true multiphase system the phases are 120 degrees out of phase with each other. We use 208VAC and 480VAC three phase in our machine rooms.

keith

-- 

Keith R. Watson                        Georgia Institute of Technology
Systems Support Specialist IV          College of Computing
keith.watson at cc.gatech.edu             801 Atlantic Drive NW
(404) 385-7401                         Atlanta, GA  30332-0280