Re: [TCML] Re: Tar

["Bob Arenella" <rja12@xxxxxxxxxxx>]

Hi all,
                    Been lurking here for a good while. This subject brings 
up some questions about an X-Ray transformer that I'm about to put back 
together. Typical 125 KV xfmr, core strapped to brackets that are bolted to 
the cover. I've got new Shell Diala A oil. The xfmr has been out of oil for 
about 1.5 years. I'll assume I can't just put it back together, add oil & 
let 'er rip.

                    My questions are: How can I apply vacuum to this thing 
so there are no air pockets in the windings? I don't think the cover will 
hold vacuum. Just how much vacuum does one need to accomplish this? I see 
some small, inexpensive pumps on eBay that are rated at 3-5 CFM & will draw 
30" Hg. would something like that fill the bill? Would the vacuum pump used 
to service auto AC systems work?

                    A friend suggested heating up the core to about 140 F & 
just lowering it into the much cooler oil. I don't want to ruin this thing 
the first time I fire it up. Any & all suggestions greatly appreciated !!

Thank you,
Bob A
----- Original Message ----- 
From: "Russell L Thornton" <Russell.L.Thornton@xxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, January 20, 2009 9:38 AM
Subject: [TCML] Re: Tar


> Ed,
> The high voltage transformers that are filled with oil are subjected to
> vacuum to pull the air out of all the
> little crannies.  I would expect that wax and tar, being less fluid, would
> especially need this procedure to
> be sure there are no pockets of air.  With the heat requirements you are
> looking at a more complex setup.
> You may want to consider the oil again and maybe change your container.
> Just my 2 cents soon to be 1 cent.
> Russell at the Cape...Go Delta!
>
>
>
> > Message: 3
> > Date: Sat, 17 Jan 2009 15:42:10 -0800
> > From: Ed Phillips <evp@xxxxxxxxxxx>
> > Subject: [TCML] TAR
> > To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> > Message-ID: <49726CD2.508@xxxxxxxxxxx>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> >   Does anyone know where to get the type of black "tar" used to pot
> > transformers?  Does anyone know the actual temperature at which it's
> > poured into the transformers?  Did a web search but got nowhere and
> > suspect that roofing tar or pitch probably isn't suitable.  I want to
> > pot a couple of GMHEI transformers in a cylinder to simulate the
> > secondary of a "spark coil" and don't want to mess with oil or the
> > like.  Paraffin wax doesn't work, at least for me, because of too many
> > bubbles - I've tried pretty hard to get rid of them [with the exception
> > of vacuum] without much luck.
> >
> > Ed
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla 

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla