28 Jul
2007
28 Jul
'07
10:07 a.m.
On 28 Jul 2007 at 10:44, William Donzelli wrote:
Limiting inrush is useless for nearly every tube made,
as the
filaments are made to deal with it anyway. The only tubes I know of
that required some sort of inrush protection were a few of the very
large transmitting types from the 1940s - the kind whose filament
current ratings are in the hundreds of Amps. Some of them even had
specific power up and power down sequences. With some of the huge
tubes later on, there was inrush protection, but that was to protect
the transformer, not the tube.
Surgistors were very popular in the 50's as either an add-on for TV
receivers or as part of the original chassis.
As far as I know, computers did not use mercury vapor
rectifiers. In
all the ones I have seen, or seen documents for, the rectifiers have
been gas types. When I was recently poking my nose into Pierce's 709
power unit (7mumblefoo?), I saw that IBM used C16J thyratrons - a
whole flock of them. Which probably makes that power unit the most
costly piece to retube these days.
I don't know about the 1600 volt supply for the Univac Solid State
machines for the clock output stage. That might be a possibility,
but I can't find a reference. Weren't some mercury vapor thyratrons
used to drive some printer and punch coils in the early systems?
Cheers,
Chuck