Re: How are 240 VAC variacs made?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com> 

Alright, its clear now. I think I have figured out how to wire a 4 pack mot
supply from a single 240 VAC variac. You are correct I want to have x-0-x
out.

---Eric
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, February 29, 2004 8:06 PM
Subject: Re: How are 240 VAC variacs made?


 > Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 >
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Sunday, February 29, 2004 2:57 PM
 > Subject: Re: How are 240 VAC variacs made?
 >
 >
 >  > Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com>
 >  >
 >  > you completely missed the point....are they center tapped to ground or
 > not?
 >  > Obviously 2x 120 vac's ganged together are or can be, but are the
single
 >  > core 240 VAC ones center tapped?
 >
 > No, they are not.. You might be hooking it across a delta connected 240 V
 > supply, and so, both wires are "hot".  That said, I will say that I have
 > seen variacs with a center tap on the winding, but they still have only
one
 > wiper.  What you're really asking is if 240V variacs have a pair of
wipers,
 > so you can feed 120-0-120 in and get x-0-x out?
 > You can do this if you're ganging multiple variacs together.
 >
 >
 > In a three phase variac, they are usually connected in Wye (star), with
the
 > low ends of the variacs tied together, even if the supply is delta fed. If
 > you hook three variacs in delta, all moving the wiper(s) does is change
the
 > relative phase between the input and output, but the voltage remains the
 > same. (draw a little picture/schematic, and this is obvious... three wires
 > in and three wires out)
 >
 >