pole pig rewinding

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

Original poster: "Mr Gregory Peters by way of Terry Fritz <teslalist-at-qwest-dot-net>" <s371034-at-student.uq.edu.au>

Hello all,


After pulling apart several pigs myself, I feel somewhat qualified to 
comment on the possibility of rewinding one. Some points:


1. Firstly, pulling the core out of a pig is a real pain in the butt. You 
will have to deal with 50 litres or so of oil. The core will be messy, oily 
and probably rusty if the pig is very old. Mine had a good 1/2" of water in 
the bottom.

2. For reduced leakage flux and increased efficiency, the HV winding is 
generally wound directly over the LV one on the same former. And the 
windings are split in two and sometimes can be hooked in series and/or 
parallel to change the input/output values. The former is several peices of 
paper strip wound with more paper sheet, and the whole assembly is held 
together by the windings. To remove only the HV winding and use the 
original LV winding would be quite hard.

3.The core in both pigs was of the "C" variety. It was held together by a 
large stainless strap. Quite easy to pull apart and easy to work with. Also 
a more efficient core configuration than EI types. Sliding the core out of 
the windings required many good hits with a sledge hammer.


4. The outer layers on the HV winding were ?cotton? covered. I assume this 
is because more stress would be placed on these windings, especially if hit 
by lightning?? The inner layers were normal magnet wire, close wound.

Now some ideas:


1. Unless you REALLY want to wind a tranny yourself, is the effort worth 
it? We are talking hours of work, like winding a few tesla secondaries, but 
harder, with inter layer insulation and stuff. It will break your heart if 
it arcs over and you need to pull the core again!!!!


2. If you get someone else to do it, it will cost heaps. I priced rewinding 
a single phase 10kVA tranny at nearly A$1000 (~500 USD). This does not 
include the new oil you would probably want to use.

3. I got 3 pigs for free (two are near new and reconditioned), though I'm 
not saying from where in case someone tries the same idea, gets hurt, and 
sues them. But in any case, why not just spend the bucks and get a new pig?

4. The cores make great cores for inductive ballasts. Simply wind some 
turns around the core and vary the air gap. Very Nice!

5. Otherwise, use the pig for a big tube coil or something.

Basically, I feel you are wasting alot of time and money rewinding a pig 
unless you a a real DIYer who just wants to say he has done it, but I liken 
this to winding your own motor for your SRSG! Compared to Australia, PDTs 
seem to grow on trees in the US, especially when people on the list are 
happy to sell them for under $200. I had to search for six months to find one.

Cheers,



Greg Peters
Department of Earth Sciences,
University of Queensland, Australia
Phone: 0402 841 677
http://www.geocities-dot-com/gregjpeters