[NLRS] Transformer oil

[Dr. Gerald N. Johnson, electrical engineer]

Transformer oil is flammable. Takes over 500�F to ignite it. Good
transformer oil is essentially mineral oil USP as sold in the drug store
though good transformer oil may be cleaner, having less water. Because
transformer oil will burn, when used in any quantity inside buildings
its required to be in fireproof vaults with oil collecting basins. There
are silicone based replacements that are harder to ignite and allow less
stringent regulations.

Lack of water is a benefit in transformer oils since much of the oil
cooled transformer's insulation is based on paper. Finding water in a
transformer's oil is taken as a hint of the paper breaking down.

Transformer oils in the past sometimes used a polychlorinated biphenyl,
called Askerel among other names. It has a sweet odor, and some
varieties have been accused of causing cancer. There are chemically at
least 4 different chlorinated biphenyls, having 1 to 4 chlorine atoms
per molecule. All have been painted with the same brush, good or bad.
The pcb based transformer oils do not naturally break down with age and
heat or ingestion in critters so when they reach the environment they
stay. At least in one area in Japan some variety of pcb oil was mixed
with salad oil and it did have an adverse effect on the population. Once
oil carrying and cleaning apparatus of power companies is contaminated
with the pcb based oils, no pure mineral oil passes through without
gathering detectable (maybe in parts per billion) pcb. And that makes no
one willing to handle used transformer oil, even when declared pcb free.
Down river from major transformer manufacturing plants in New York,
there is a silt layer of pcb that General Electric may have to dig up
and eat.

The hassle is least with mineral oil USP from the drug store. And its
decent transformer oil. Good for dummy loads also.

In the wake of declaring freons unwanted, many paint spray cans now use
propane for propellent, to better burn when used improperly.

73, Jerry, K0CQ
-- 
Entire content copyright Dr. Gerald N. Johnson. Reproduction by
permission only.