RE: [TCML] De-potting NSTs? ? ? Dialectric success

["Jim Mora" <jmora@xxxxxxxxxxx>]

Hello,

I un-potted a France 12/30 that was old and the tar was cracked and
internally arcing. After freezing it, barbequing it, than soaking the mess
in gasoline (not recommended). I came out with a very clean transformer. I
let it sit in the sun a couple days on a newspaper.

I removed half the shunts on both sides counting them. I then found a
suitable Tupperware container (PE) and cut an acrylic top that fit nicely to
a lip near the top inside the vessel.

For my dielectric, I bought a couple boxes of paraffin and 4 large size
white petroleum jelly containers and carefully melted them together on the
stove.

While this was in progress, I preheated the core in the oven on low.

I poured the molten solution onto the transformer in the tub tapping on it
to dislodge any small bubbles. I am confident the winding and laminations
were well permeated. After a few hours of cooling, I then melted a couple of
white taper candles( they are the firmest of waxes) and toped it off with
that. The acrylic was connected to the low and HV and center tap with
smallish feed-though insulators. 

I haven't measured the line current but it has a hot arc easily like that of
a 12/60 or more. I plan to use it for winter in house fun. It has handles,
is relatively lite, and is easy to carry around!

...A nice break from my engine crane and big iron :-)

Jim 
 

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Neal Namowicz
Sent: Thursday, December 06, 2007 9:50 PM
To: Tesla Coil Mailing List
Subject: Re: [TCML] De-potting NSTs? ? ?

Can a more common, more accessible (and less expensive) oil, such as mineral

oil, be substituted? Actually, I may be jumping to conclusions re: the cost 
of legit xmfr oil. How do they compare in price, and is xmfr oil readily 
available "over the counter"? (I'm thinking about shipping costs) I'm 
located in the near-west Chicago 'burbs, so there may be someplace fairly 
close. Anybody have any ideas?

While we're on the topic of removing shunts, also, I'm assuming that the 
more shunts removed, the greater the stress placed on the secondary 
windings. So what's the possibility of putting 2 9kv nst's in series to get 
18kv? Added stress to the windings will happen, but is it worse than 
removing shunts? I ask because 9kv units I have, I just kind of put them 
aside after I got the 15kv unit. If I remember correctly, aren't nst's 
center-tapped to the case? So if two are put in series and the cases are 
just allowed to "float" with no grounding, does that get around the 
center-tap issue?

Thanks all,

Neal.
>
>
> Or, drop it in a tupperware tank full of xmfr oil so it gets better 
> cooling and protection.
>
> Dr. Resonance
>
> - - -  snip - - -
>
>>
>> I depotted a 9000 v 30 mil allison transformer, I put the whole thing on 
>> a cookie sheet and put it in my gas grill. i tried to keep the grill 
>> around 250-300 degrees. after about 10 minutes the tar started meltin, 
>> after about 30 you could pour it out of the tranny box. I have to caution

>> this is very messy! after you get the inards out, (most people dont 
>> recomend) i used gasoline to clean the actual transformer. When you got 
>> it all cleaned it is easy to remove the shunts. You shouldnt go over 3x 
>> (i heard from someone down the line) the I rating, i went 330 ma out of a

>> 30 ma, it worked for a lil while but not for long. If you up your 
>> amperage your gonna have to get a bigger tank cap though, use java tC to 
>> find out what your gonna have to do.
>
>
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> 


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