RE: PDT (Pig) failure modes

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

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