[AMRadio] Ferroresonant transformer revisited

Jim candela jcandela at prodigy.net
Sun May 7 19:00:26 EDT 2006

>I worked with these things 38 years and don't remember
>but one capacitor failing in one which was easily replaced and returned to
>service. Hope this non-answer helps. 73 Mike

Good input there Mike.

Years ago I worked for a lighting company that made ballasts and fixtures
for HID lighting in industrial applications such as factories, or airplane
hangers. These ballasts were horribly inefficient, and ran hotter then heck.
It is amusing because the lamps were very efficient types such as metal
halide, or high pressure sodium. To cut costs, the ballast laminations were
pretty thick, and then the gaps were closed by welding the core together.
Needless to say, core loss from Eddie current loss was high. Then for every
technical problem there is a marketing solution. These things were failing
right and left. The engineers decided that the most cost effective solution
was to use a higher temperature rated magnet wire. They chose class H
insulation that could run at 100 C or higher without failure.

At that time (1979) there was an old warehouse filled to the rafters with
leaking PCB capacitors, and this was in a very environmentally fragile zone
that feeds water into an Aquifer that is the main water supply for San

I guess I'm wandering a bit..............


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