[geeks] D'OH!

Greg A. Woods woods at weird.com
Fri Feb 1 18:26:37 CST 2002


[ On Friday, February 1, 2002 at 14:35:59 (-0500), James Sharp wrote: ]
> Subject: Re: [geeks] D'OH!
>
> The electric stove in my place is run off split phase 220V @ 20A.

It's best not to use the infinitely confusing phrase "split phase", at
least not without qualifying it with a number.

Your house is undoutably fed single-phase 220VAC from a centre-tapped
single-phase transformer.  A "neutral" line from the centre-tap allows
for connecting 110VAC circuits to the same service.

Your 110VAC circuits are actually the strange critters since they are
fed from one side or another of the transformer.  They are the "split"
single-phase circuits, not your stove.  The neutral, BTW, is not
"ground" -- though it shouldn't have a potential very far from earth
ground, and if it does there's usually either a wiring problem, or your
transformer is under stress from an uneven load.

You can generally tell the number of phases by counting the number of
high-tension feed lines to the transformer (though sometimes there are
three separate transformers at points in the three-phase distribution
system -- one for each phase).

-- 
								Greg A. Woods

+1 416 218-0098;  <gwoods at acm.org>;  <g.a.woods at ieee.org>;  <woods at robohack.ca>
Planix, Inc. <woods at planix.com>; VE3TCP; Secrets of the Weird <woods at weird.com>



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