Transformer solvent soaking questions & safety

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "M G" <gt4awd@xxxxxxxxx>


A few weeks ago I melted most of the tar out of a damaged fraceformer 
15kv/30ma NST. One of the high voltage insulators was damaged during 
shipping, and there is a problem with the core, most likely just 
carbon tracking in the tar. The transformer was a warrentied NST.  I 
was able to remove most of the tar, but a good amount still remained. 
The transformer core is still in the case, because it would not budge 
after the heating process. Today I started soaking the opened case in 
a large galvanized steel container using kerosene. Right now the 
container is in the garage soaking, with a thick plastic cover over 
it. Should I move it outside for safety reasons? The garage door can 
be left slightly cracked for ventillation.



I have no meters to test the actual output of the transformer, but I 
did test it before and after the heating process. Before, the output 
would not climb a jacobs ladder past about half an inch separation. 
After, the arc was able to reach the top, about 2.50" separation. My 
first transformer, a 9kv 30ma Allanson, seems to still output more 
secondary current the the mostly unpotted franceformer. The 
Allanson's electrical arc is a lot louder, and thicker, than the 
fraceformers. The franceformers arc also seems to have a wierd sound 
to it. Almost as if the arc is oscillating, cutting in and out really fast.



After removing most of the tar during the heating process I found 
that the core only had one side grounded. At each end of the core is 
a attached small "eye" connection. Only one side was grounded to the 
case. This may be normal, but it is my first time unpotting a 
transformer so I would not know. Some time ago I remember reading a 
website that showed the depotting process of an old damaged NST. The 
person decided to setup the transformer to be ran ungrounded, giving 
the full voltage output of the transformer. To do this, if I am 
remembering correctly, he first removed the NST core ground to case 
connection, and then rectified the output to direct current. Does 
this sound like a good idea? Would my coil setup have to be 
redesigned into a DC coil in order to use a transformer with 
rectified output? Can the NST be ran without being rectified, 
ungrounded, and some shunting removed or is it likely to just burn up?



If you have any replies to the safe use of kerosene please reply 
offlist. I would like to get any information as soon as possible to 
avoid any dangers. Replies to the transformer questions can be made 
on list, as the transformer will be soaking for a few days.

Thanks a lot,

Matt G.

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