Re: PDT (Pig) failure modes

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

Original poster: "Steve White by way of Terry Fritz <twftesla-at-qwest-dot-net>" <slwhite-at-zeus.ia-dot-net>

Just a note of caution. Since T&R again seems to be willing to sell pigs for
Tesla coil use, let us be careful not to antagonize them by asking for
replacements, etc.. Even though the transformer may have indeed been
defective, I think it would be wiser just to eat one every now and then than
to beat up on them because one of their tranformers failed under Tesla coil
duty. I bought mine from T&R about a year ago and I want to keep them as a
reliable supplier.

Steve: Coiling in Iowa

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, September 17, 2002 11:30 AM
Subject: RE: PDT (Pig) failure modes


> Original poster: "Dave Hartwick by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <ddhartwick-at-earthlink-dot-net>
>
> Godfrey,
> Very interesting. I never considered thermal expansion as a factor.
>
> It is clear that repair is virtually impossible unless rewinding is
> persued--forget it. By the time I do that, I may as well obtain
laminations
> and build a xfmr from scratch that is specifically designed for Tesla
duty.
> One feature of such a xfmr would be easily removable windings and a
variable
> magnetic shunt.
>
> I'm SURE Tesla duty would not be considered normal by T&R! I did talk to
> them yesterday and they are not willing to replace the core, which is
> expected. They are willing to sell me a complete replacement unit, no
> questions asked concerning usage. Good enough for me, though I might buy
one
> from Dr. Resonance. I think there is some water floating around in the
> bottom of the tank of this dead PDT, also some rusty chunks of something.
I
> must think that I received the unit from T&R in this condition since it's
> just been sitting in my basement, well protected.
> Dave
>
>
>
> Original poster: "Godfrey Loudner by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <ggreen-at-gwtc-dot-net>
>
> Hi Dave
>
> I had a similar problem with an old 7.5kVA industrial 120/240/480
> transformer. By paralleling the two 120 windings, I could get up to 60
amps
> at 120 with a 240 feed. This was a great high current supply for playing
> around with MOTs. One day the transformer went on a dead internal short
and
> the breakers tripped. The next day I was very surprised that the
transformer
> was working, but it shorted again after awhile. I decided to scrap the
> transformer for the nice heavy copper wire. After much agony, I finally
> freed the winding from the core. Upon removing the top layer of paper, I
> could see burn marks between two adjacent turns. I think that heat
expansion
> would eventually push the two weak spots together, and after cooling off
the
> weak spots would separate. Maybe something like this is the problem with
> your pole pig.
>
> When I got my pigs from T&R, I was told that they were under guarantee for
> one year for normal usage. I forgot to ask if tesla coiling was considered
> normal.
>
> Godfrey Loudner
>
> > What is truly a mystery about this thing is that it either works
> perfectly,
> > or acts like there is a crowbar dead short across the primary.  Well, at
> this point, I'm tentatively pronouncing Ariel dead. I'm going to
> > call T&R to see if they can supply a replacement core so that I can
> perform
> > transplant surgery.
> > Dave H
>
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