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Re: Variac Troubles



Original poster: "BunnyKiller by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bigfoo39-at-telocity-dot-com>

Tesla list wrote:

>Original poster: "Marry Krutsch by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <u236-at-earthlink-dot-net>
>
>Hi All,
>
>	I just bought what APPEARED to be a 1256 Powerstat variac.  The trouble
>is, it saturates beyond 120 VAC in.  The new unit is identical to my
>existing 1256, except for the wiring beneath the binding posts.  The new
>unit looks like it uses the whole winding, but there are wires that go
>someplace INSIDE the core.  I can't tell where these wires go.
>
>	Is it possible that this variac uses a different core material, which
>saturates more easily?  I say again that the two units are IDENTICAL in
>every way other than that stated above.
>
>Please help, I'm stumped :-P.
>Winston K.
>
>
>
>
>
Hi Winston....

there should be 3 or 5 lugs on the plate in front...  1,2,4,5 connect to 
the outer core winding #3 is the wiper,  2 & 4 will be attached to the 
core winding about 1/5 the way from the start and stop points of the 
main winding. ( this is for a standard variac)

Considering what you are saying about wires dissapearing to the inside 
of the core....  what you may have here is an isolated winding type of  
variac. This type is where the "secondary" side of the variac is not 
connected ( not center tapped) to the primary. ( actually I prefer this 
type ) it behaves more like the "true" transformer .. using a seperate 
variable primary and a seperate secondary winding. You will probably see 
2 or 3 wires go "into" the core  2 of them will be the secondary output 
and in some cases a 3rd wire is the loop back from the wiper and primary 
coil.


Scot D