Runbaken Oil Coils

[A G Wood]

I dont know when PCBs arrived, probably in the 1950s along with many other nasties. Presumably transformers were oil cooled before PCBs. And presumably when used the PCB concentartion was more like 100%.

There's a fairly comprehensive article (particularly the "History" paragraph) on Polychlorinated biphenyl in Wikipedia, Bob. I gather transformers were oil cooled pre-1930 using 'ordinary' mineral oil but PCB was the ideal material for the job, being amongst other things, non-flammable. Apart from the unfortunate eco-toxic aspects of course.

[Erich]

While I appreciate that PCB insulated coils offer some advantages by generating higher voltages for sparking(better able to leap a large gap) I'd rather not have one around. As AG Wood notes above, they began to be used around 1929. I'm not sure the vintage of Runbaken coils mentioned, but presumably they were post 1929. PCBs are nasty chemicals, slow to degrade, cause cancer, and three headed chickens.

Erich in Mukilteo

https://en.wikipedia.org/wiki/Polychlorinated_biphenyl

[Bob Culver]

Thanks AG

It is tempting but I will resist researching the development of transfornr cooling over the decades. Huge pressure in this country to learn the stone age language but I am resisting that too although it would  likley prove more useful.