This is an old GE Pyranol branded capacitor I have. It’s rated 2 microfarads and at 1000 VDC or 440 VAC at 60 cycles, maximum. I was wondering if anyone here can date it based on the numbers stamped in the case. I know it has to be pre-1960, as the frequency is listed in cycles, not Hertz, as Hertz didn’t exist until it was established as the SI unit for frequency in 1960.

The properties of polychlorinated biphenyls are very good from an electrical standpoint. It’s too bad that they are toxic and cause environmental issues. Personally, I just like the fact that they won’t burn. Using mineral oil in a transformer or capacitor makes me uncomfortable. We figured out it was a bad idea in the early 20th century, and invented polychlorinated napthalenes, then polychlorinated biphynels, which have better electrical properties and are less toxic than the PCNs, to replace mineral oil. The whole situation is a bit of a catch-22, but I’d personally rather not have a giant fireball form whenever a substation transformer or pole transformer arcs or shorts.