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Re: where to get dielectric oil? =
Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
Hi David,
Phenolic type "GPO3" is very tracking resistant. It is a red to pink
polyester phenolic that is used in all kinds of HV electrical
stuff. McMaster sells it somewhere but I can't find it at the
moment... Polypropylene will burn up bad, but it is very resistant to
failing in the first place that may indeed fix the problem ;-)) G-10 is
nice for low voltage stuff but GPO3 is best of HV...
Water at the bottom of a container of transformer oil is usually considered
a disaster... Oil can hold a lot of water, thus the vacuuming of
refrigeration systems and all to purge out all the water... The thing I
saw for a big substation transformer oil filling, heated the oil to boil
off water under vacuum in a continuous loop recirculating system. Quite an
operation!! It took days... That transformer slide 3 feet on the rail car
it was delivered on (200 tons!!) and came damaged. They "thought" they had
it all fixed... It failed within a year and destroyed the substation
($15,000,000!!!)... But the mechanical damage was to blame, not the
oil. They tested transformer oils all the time for breakdown as a periodic
check to be sure water was not getting in...
If you really care, I would get that nice new Shell oil and all... I
really worry about used oils or "just any" oils for things that really
matter... "Water" is the worst enemy. I seem to remember a "descant" that
works inside transformer oil too.... But just "clean and dry" will fix
99.9% of problems... I would consider sloshing around alcohol, like the
gallon tins from the hardware store first to clean things if needed. Then
heat the thing up for a day or so to drive out water. "Any oils" may not
have all the "bad oils" removed that could attack transformer shellacs on
the wires and all too... "Detergent" motor oils are designed to eat though
shellacs which may not be a good thing in a tranny!!
If you get oil from Shell, please tell us how it goes (cost??)... They
seem very happy to sell it to anyone they can find ;-))
Cheers,
Terry
At 12:31 PM 8/19/2004, you wrote:
>Hi Terry, all,
>
>Yes, this is Steve Flowers and I have obtained a total of three x-ray
>transformers from him in the past, including my latest 150 kV, 600
>mA "catch" just a few weeks ago for $50 ;^)) This latest transformer
>"catch" was the one that I was having trouble with the phenolic sup-
>ports for one of the HV output tabs from the transformer-to-rectifier
>assemblies carbon tracking to the grounded steel walls of the tank and ended
>up replacing the phenolic support piece three times before
>finally following Dr. R's advice and replacing the phenolic with G-10.
>I didn't have any more suitable scrap pieces of G-10 to replace the
>phenolic support on the other side (strangely enough, in all three
>carbon tracking incidents, it was always the same phenolic support
>that failed; the one on the opposite side never failed). However, I
>still replaced the "non-tracking" phenolic support with a piece of
>PE from a cheap poly cutting board. So far this has worked fine.
>
>But getting back to the oil issue, the oil that Steve has on ebay
>all of the time is oil that he has drained from x-ray transformers.
>He now lives within 100 miles from me and that's how I was
>able to pick up the latest transformer w/out concern for the freight
>arrangement and cost. Like you, though, I'm a little concerned
>about the purity of his oil since it's drained from old transformers
>and he doesn't have the proper facilities for maintaining or retaining
>the strengent purity levels required for dielectric oil. However, I have
>used some of Steve's dielectric oil without breakdown problems but
>in one of the bottles I did notice a few "bubbles" of water in the
>bottom. I may try a local oil jobber and if the price is too high, then
>I'll just call on Steve ;^)
>
>David
>
>
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Thursday, August 19, 2004 9:51 AM
>Subject: RE: where to get dielectric oil? =
>
>
> > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
> >
> > Hi,
> >
> > This Ebay guy has been selling oil for years:
> >
> >
>http://cgi.ebay-dot-com/ws/eBayISAPI.dll?ViewItem&category=4660&item=3833810451
> >
> > I would worry about contamination... Transformer oil and the use it goes
> > into needs to be very clean and free of water. Big substation
>transformers
> > go through a dramatic oil drying and cleaning process (two big semis full
> > of equipment)... But if the thing is clean and you heat it say in the
>sun,
> > that should be fine.
> >
> > Transformer oil is free of light solvents and other odd oils that might
> > attack insulation and such over time. It also has a controlled dielectric
> > constant with is sometimes important to the HV industry. So it is better
> > than just any oil if the application is really demanding. Testing it with
> > high voltage first is a good idea if it is really being pushed hard.
> >
> > Cheers,
> >
> > Terry
> >
> > At 05:47 AM 8/19/2004, you wrote:
> > >About 4 years ago I tested several different type of oils and posted the
> > >results here. I bought some HV oil from the power company. I
>discovered
> > >not to walk into the main office and ask to buy HV oil you will be told
> > >that they do not sell it. Go to the power company maintenance department
> > >and ask to buy HV oil. They will sell it to you for about $2.00 a
>gallon.
> > >I tested lamp oil, 10wt non detergent motor oil, kerosene, diesel fuel,
>and
> > >several other oils. As long as they have no additives they will all work
> > >fine. Lamp oil from Wal Mart seems to be the easiest for everyone to
>find
> > >and it comes in quarts and gallons. Get uncented lamp oil 100% pure
>oil.
> > >I tested the oil by placing an adjustable spark gap under the oil and
> > >connecting it to 15KV power supply. Measure the gap and try different
> > >oils to see which one works best. Put a cap in parallel with your
> > >transformer and test it again.
> > >
> > >Gary Weaver
> > >gary350-at-earthlink-dot-net
> > >Why Wait? Move to EarthLink.
> > >
> > >
> > > > [Original Message]
> > > > From: Tesla list <tesla-at-pupman-dot-com>
> > > > To: <tesla-at-pupman-dot-com>
> > > > Date: 8/18/2004 10:45:09 PM
> > > > Subject: where to get dielectric oil?
> > > >
> > > > Original poster: "David Rieben" <drieben-at-midsouth.rr-dot-com>
> > > >
> > > > Hi list,
> > > >
> > > > I'm sure that this has been covered before, but where can I
> > > > get new dielectric transformer oil (like Shell Diala?) in small
> > > > quantities, like 5 gallon buckets? I assume just call one of
> > > > the local oil manufacturers?
> > > >
> > > > David
> > > >
> > > >
> >
> >