[Amps] contact bounce

[Jim Thomson]

Date: Sun, 4 Apr 2010 09:08:16 -0700 (PDT)
From: James Irving <k9jfk at yahoo.com>
Subject: Re: [Amps] contact bounce

Someone recently described a way to "hot shot" a relay circuit.  First...They proposed to double the voltage.
Second... Put a resistor in series with the normal speed coil.
Third... The faster speed relay would have the same value resistor, but paralleled by electrolytic cap. 

Why not try to reverse the thinking for your problem.  Instead of speeding up the output relay, slow down the input relay.  Put a low value resistor in series with the input relay... just a couple of ohms to limit current surge. After that, put a capacitor across the relay coil, just big enough to give you a couple of msec delay before the cap charges.

There will also be a slight delay on releasing the relay, but no rf should be coming from the amp.

Haven't tried it.  Would only work with dc relays, and the relay power source would need to deliver a little surge.

73, Jim, k9jfk

##  sure, that will work.   The problem with the  RJ2-B/C   and RJ-6  [ and also G-2ham] is.. the operate time is  really slow to start  with !    It's  18 msec operate.. and only 9 msec rls.  
If you slow down the  input relay... like  >18 msecs.... say  24 msecs.... you now have the relay's  sequenced right.... but it's  not  optimum overall.    On a  MK-V.. on CW mode only,  no big deal
as you can tweak the digital CW delay  from 0-30 msecs.. and simply crank it up to 30 msecs....... then nothing will  get truncated.   On  ssb, you will have RF  coming out of the yaesu within 5 msecs
of tripping the vox.   100w XCVR  RF   goes through the amps T/R relays... then the  output t/r relay operates.... now u have an open path  for the xcvr  [infinite swr], then finally, the input t/r relay operates
and  you can apply drive to cathode.   It will probably work fine on ssb.. as long as xcvr's  hi swr light doesn't come on,..or  audio sounds clipped  1st syllable. 

##  speeding up the vac relays  is no big deal, pretty straight  forward.. and easier to do  when the vac relay coil  is 12 vdc  to start with.
Another option is to speed up the  output  RJ-6... but  not the input  RJ-6. 
Another option [say for a henry 8 k]  is to use a single  sped up RJ1-A  on the  input side... and  sped up  paralleled  pair of  RJ1-A's on the output side. 
Then u have NO timing issues at all, and all vac relays operate in < 2msecs.   Use the  12 vdc  version of a GH-1 ham.... and you can re-use the existing 24 vdc  relay
supply in the  8-k  amp.   

Later... Jim   VE7RF