|
Re: Heating in 4-1/2 turn inductor GOSH!
From: coffelt2@comcast.net (coffelt2)
I tried reading and understanding most of the posts, but confess not understanding all of them.
BUT, I cannot resist inserting my "two cents" worth:
In olden days, it was quite common (but unwelcome) to have parasitic oscillations run away in large RF amplifiers. They would start all by themselves and quickly begin roasting tubes, coils, even adjacent conductive surfaces, whatever got in the way. The often encountered case would be a HF amplifier running away (self-oscillating for the unwashed) at a VHF or UHF frequency.
One common, but mysterious result was burned parts of RF chokes in the plate circuit. (you do remember tubes, right?) I think there were a couple of commercial RF chokes wound on long ceramic (steatite?) cores with assorted winding spacings on the ceramic core. Burned spots would occur in only one or two places on the length of the winding. Caused, supposedly by a high current node on a VHF or UHF resonant portion of the winding.
4 1/2 turns at 600khz must be an awfully low impedance circuit, but could be right down the alley for VHF.
Brian has my vote for barking up the right tree.
Old Chief Lynn, W7LTQ
|
