Richard wrote:
>
>
>>Hi!
>>
>>Have a nice transformer.. Large n' bulky etc!
>>2.5 kV Secondary..Low R's etc
>>
>>But is only half-filled with X-fmer oil.
>>Used in the Swedish Army long time ago.
>>
>>I'm suspecting it has PCB's in oil,
>>so kind of little bit unwilling to pour it out....
>>
>If the oil has an odor similar to moth balls, it probably contains pcb.
That's about right. Ordinary hydrocarbon-based transformer oil smells
quite different... like oil.
A simple test which is used commercially is to take a very small drop of
the oil on the end of an iron/steel wire, and burn it in a gas flame. If
the flame is green, it strongly suggests PCB. (Do this with a blowtorch
flame outdoors - not in the kitchen! Also check the flame color first
with a clean wire.)
The probability is that the transformer does not contain PCBs, since
regular transformer oil has always been OK for the kinds of transformers
we AMPites tend to use. However, PCBs were very much "in fashion" at one
time, so they were used for applications where it wasn't strictly
necessary - it's always best to check.
>If there are no leaks, add non-pcb cooling oil.
If the transformer is found to contain PCBs, I'd hesitate to mix any
other oil with it. If the PCBs are no longer fully sealed away from the
environment (especially you) then the transformer really ought to be
disposed of.
Even if the transformer contains hydrocarbon oil, it seems unwise to mix
two radically different kinds of oil without first trying a sample
outside the transformer, to check that they really do mix, and that
there are no unwanted reactions (like incompatible additives
precipitating out).
Any added oil must be low-vapor, high-flashpoint grade - in other words,
real transformer oil. Note that engine oil contains many additives (like
detergents) that have no place inside a transformer.
Also the transformer should be re-sealed with a small amount of air
inside, as a cushion against thermal expansion. When I've done that,
I've also mounted the transformer in a plastic container just in case
any more oil weeps out... which it usually has, over months and years of
thermal cycling.
> If there's a leak and
>you want to get rid of the remaining pcb, pour it in a steel bucket,
>insert rolled up newspapers for a wick, wet the wick with kerosene, and
>burn it. Burning (heat/oxygen) is one pcb disposal method used by
>commercial waste disposers.
>
DO NOT DO THIS!!! PCBs have to be incinerated at a very high flame
temperature in special equipment, to avoid spreading vapors and
half-burnt products that are even worse!
To find out how to dispose of PCBs in your part of the world, search the
web for (PCB + disposal + <your state or local authority name>).
--
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
New e-mail: g3sek@ifwtech.co.uk
New website: http://www.ifwtech.co.uk/g3sek
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