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Re: Here pig pig pig


Hi Bill,  There is an easier way to "un-pot" these things.  I've un potted
many NSTs and have found that heating them is very messy and also has the
undesirable effect of making the tar penetrate even deeper into the
laminates and windings.  What I do is use an air chisle to break open the
case.  then I throw the whole black mess into the deep freezer for the
night.  Then, in the morning, I just go out and drop the thing on the ground
and wack it a few times with the hammer.  I then simply sweep up the mess of
frozen tar and take it apart.

Give it a try, works great.!

-Keith


Tesla List wrote:

> Original Poster: "Bill the arcstarter" <arcstarter-at-hotmail-dot-com>
>
> Coilers,
>  Well I am in possession of my pig!  No - it didn't weigh a mere 125 lbs
> as advertised.  The true weight is 300 lbs + 25 for the pallet it was
> strapped to!
>
>  I am now famous at work for having a pole transformer delivered to the
> loading dock!  I came back with my pickup and grabbed it (lined up the
> powered loading elevator with the bed of the truck and pushed it in
> using a pallet jack).
>
>  Just tonight I completed welding a cable winch onto the end of my boom
> arm - and was able to use said instrument to get the transformer off the
> truck, onto the ground. :)
>
>  The transformer appears to be BRAND NEW - no rust, white paint, the
> wire lugs are tight down and don't appear to have ever clamped a cable.
> The can is roughly 16 inches in diameter and 28 inches tall.  The input
> insulator is over a foot long which places the top of the insulator at
> about 41 inches off the ground!  It isn't small or portable and is not
> quite what I expected.
>
>  Total bill was $94 + $70 s/h.  Not a bad deal.  I will get the relevant
> addresses/URLs for anyone else interested in adopting such an electric
> animal.  I also have yet to pursue those mini-pigs in the local scrap
> yard.
>
>  There is no top access plate so I don't think it has a tap switch.  I
> can take the entire top off (including the input bushing) which I will
> do to inspect the insides.
>
>  There is what appears to be a pressure blow-off port at the top of the
> can. (a spring-loaded pull-ring)
>
>  It contains the traditional three lugs for 120-0-120 connection, and
> the '0', or neutral lug is also bussed to the case of the transformer
> (this is removable).  There is also a separate lug welded right to the
> case.
>
>  I'm going to have to find some sort of wheeled platform for this thing
> to sit on.  Either that or I'll put wheels on the pallet and call it
> done!!
>
>  I was thinking about how to power the darn thing...  I have a 240 v 28
> amp variac and various limiting devices (including a welder).  But the
> problem is that if I use the variac - what becomes of the neutral
> connection on the pig?  I can't connect it to the neutral bus - since if
> I did - then one 120 volt primary of the pig would always see a full 120
> volts (from N to Hot).  Also - since I have only one HV output and the
> other side is connected to the case - I'd really need to keep the case
> grounded and connected to neutral.  The only solution I see is to use an
> isolation transformer between the variac and the pig.  This should allow
> me to tie the pig's N to system N/ground, and power the pig's 12v lugs
> off the isolation transformer.
>
>  It just so happens that I have a 20 amp 240v toroidal 1:1 isolation
> transformer!
>
>  Does anyone think I should break the pig's N-to-case link, tie the
> pig's case to a good RF ground, and then tie the pig's N to the power
> neutral?  I think that might be the best plan.
>
>  Oh - I depotted our 37 amp line filter which the tesla coil killed.  It
> is hard to tell but it looks like the RF arc'd from one hot wire,
> through the potting tar, to the case.  That tar just barely became soft
> at 350 degrees (in a toaster oven).  I would think that the heat time to
> depot a large neon would be at least 12 hrs since this 4x3x1 inch filter
> took over 2 hrs to melt and there wasn't any iron to heat either!
>
> More later.  Comments invited.
>
> -Bill
>
>
>
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