Here in the USA distribution transformer manufacturing plants make it a =
practice to cover the entire winding as well as the high voltage and low =
voltage bushings (connectors) with transformer oil.
More than likely, if the oil in your transformer has been in it a long =
time, contains moisture and would possibly arc internally under voltage =
stress. The only way used over here in the USA to remove the moisture =
is through a degassification process where the oil is placed into a =
pressure vessel and a hard vacuum is pulled on it while the oil is =
heated in the pressure vessel. As the oil is pumped through the =
pressure vessel under vacuum conditions, gases as well as moisture is =
removed thus increasing the breakdown voltage of the transformer oil.
Under no circumstances would I try to mix the oil especially if you =
think the original oil you have contains PCB's. Keep in mind though =
that in a transformer manufacturing facility, just prior to filling the =
transformer tank with oil, the chamber that the transformer is in is =
also pumped down to vacuum conditions and then filled with oil. That's =
really the only way I know of to be reasonably certain that oil has =
passed through the channels of the coil which are usually made up of =
dried maple wood separating the individual layers of the coil windings. =
Simply pouring it in through the ducts/channels simply will not get the =
job done without evacuation of air. Remember the oil in a transformer =
is there for two reasons. To help disperse or transmit the heat away =
from the coil/core area and to increase the dielectric strength.
73,
J. Leon Pringle, Jr W5NA
Hope this comment has helped you
----- Original Message -----=20
From: "G.Johansson" <crabspider@telia.com>
To: "Paul Kiesel" <k7cw@yahoo.com>; <amps@contesting.com>
Sent: Wednesday, May 29, 2002 2:47 PM
Subject: Re: [Amps] Transformer oil?
> OK..
>=20
> No, I'm not sure about if the transformer is designed for=20
> being filled all up. But I know for sure that some of the=20
> 'substance' has had it's way out.
>=20
> This because of oil on the paper that I wrapped around=20
> the beast!
>=20
> I'm not sure on how much. It could be just a fraction missing
> but also could be more than that. Hard to tell..
>=20
> It's so dark inside that darn thing!! Just a 4 mm drain pipe
> (exhaust pipe if boiling starts?)
>=20
>=20
> /Joe
>=20
>=20
> At 12:00 29/05/2002 -0700, you wrote:
> >Hi Joe,
> >
> >I wouldn't mix the different oils.
> >
> >But, I have a question: Are you sure that the
> >transformer needs to be "full" of oil? It may be that
> >the transformer is designed for the amount of oil that
> >is in it now.
> >
> >73,
> >Paul, K7CW/VE7RCW
> >
> >--- "G.Johansson" <crabspider@telia.com> wrote:
> >> Hi!
> >>=20
> >> Have a nice transformer.. Large n' bulky etc!
> >> 2.5 kV Secondary..Low R's etc
> >>=20
> >> But is only half-filled with X-fmer oil.
> >> Used in the Swedish Army long time ago.
> >>=20
> >> I'm suspecting it has PCB's in oil,
> >> so kind of little bit unwilling to pour it out....
> >>=20
> >> So the question is :
> >> Is it possible just to top 'her' up without removing
> >> the old stuff?
> >>=20
> >> What will happen if two different oils are blended=20
> >> when it comes to boiling temps etc?
> >> Xfmr oils often has a low boiling temp type 140 c
> >> (Guess the thing has to work when it's cold outside
> >> aswell
> >> without going into a half-liquid state? ;o)
> >> as opposed the oil I were thinking of..compressor
> >> oil,
> >> or something like that.
> >>=20
> >> The compressor oil is somewhere around the 190's or
> >> more.
> >>=20
> >> So what do you folks think?
> >>=20
> >> 1) Top her up with another oil?
> >> 2) Remove PCB-oil, give her compressor oil?
> >> 3) Blend it like Whiskeys?
> >>=20
> >>=20
> >> 73's
> >> Joe aka SM0EJR
> >>=20
> >>=20
> >>=20
> >> _______________________________________________
> >> Amps mailing list
> >> Amps@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> >__________________________________________________
> >Do You Yahoo!?
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> >http://fifaworldcup.yahoo.com
> >
>=20
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