[Amps] Plate modulation from power supply ripple?

[Jim Thomson]

Date: Fri, 4 Oct 2013 08:26:13 -0400 (EDT)
From: TexasRF at aol.com
To: ww1c at outlook.com, garyschafer at comcast.net, amps at contesting.com
Subject: Re: [Amps] Plate modulation from power supply ripple?

 
My current interest is mainly in microwave eme operation. Traveling wave  
tubes are used to generate power. The homebrew power supplies have a lot of  
filter C in the helix supply to reduce hum on the transmitted signal. After 
this  discussion I am wondering if there may be more C than necessary. 
Normally it  would not matter but if there is a flashover in the twt the helix 
structure  could be damaged. There are trip circuits to shut the power supply 
down but most  of the stored energy would be dissipated in the helix.
 
73,
Gerald K5GW

##  How much B+   ??    How much plate current ??  Just put a 50 ohm glitch R
in series with the  B+.... and wire a fast hv fuse just in front of the 50 ohm glitch.
Anything arcs, the glitch limits the fault current to a safer value.   The HV fuse interupts
the fault current..and  will easily do that in less than 2 msecs.   But you have to size the
fusing wire correctly.    Add the glitch +  HV fuse on top of your existing protection. 

Jim  VE7RF