Ampers:
In 1987, Eimac published a 4-page technical brief on Fault Protection.
It mentioned several references that were at that time out of print, and
I am interested in finding them.
The paper discusses how a fault is detected in the B+ supply to the
tube, and how to divert appropriate energy away from the tube to prevent
internal damage to the tube structure(s).
The following actions were taken:
1. The primary was shut off, so that the only energy to be absorbed was
that energy stored in the filter cap;
2. The B+ was diverted to an energy absorbing device capable of taking
the full hit, and not letting go too soon-which would allow reverse EMF
to 'ring' and still do damage.
Unfortunately, the article did not provide much in the way of detail on
the energy diverter/absorber. Ten years later, this should be an easier
task to implement. I am interested in any work done in this regard.
The final result is to react in a few tens of uSec's to limit the energy
delivered to the tube to just 4 - 50 joules (depending on the particular
tube).
Any input on sources and ideas would be appreciated.
Vince Fedele
WA2PKE
References:
1. "Capacitor Discharge and Crowbar Service Application Notes M-1256",
General Electric Company, Tube Products Division, Schenectady, NY 12345.
2. "Ignitrons, Capacitor Discharge, and Crowbar Service PT-57A", General
Electric Company, Tube Products Division, Schenectady, NY 12345.
3. "The Fault Diverter - A Protective Device for High Powered Electron
Tubes" by R.H. Smith, August, 1957, Lawrence Radiation Laboratory Report
UCRL-3701, Univ. of Cal. Lawrence Livermore Laboratory, P.O. Box 808,
Livermore, CA 94550.
4. "Vacuum Arcs - Theory and Application", by J.<. Lafferty, John Wiley
and Sons, NY. ISBN 0-470-06506-4.
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