[Amps] Glitch resistor + fuse?

[Jim W7RY]

I'm pretty sure they are .82 Ohms at 2 watts. There are lots of them on EBay 
for free shipping and small quantities.

73
Jim W7RY


-----Original Message----- 
From: Jim Thomson
Sent: Wednesday, November 15, 2017 1:15 PM
To: amps at contesting.com
Subject: [Amps] Glitch resistor + fuse?

Date: Wed, 15 Nov 2017 09:49:54 -0600
From: "Doug Renwick" <ve5ra at sasktel.net>
To: <amps at contesting.com>
Subject: [Amps]  Glitch resistor + fuse?


<The Tentec Titan amp uses a single 10 ohm 25watt ohmite.

<Doug

##  with say 1.5 A of plate current, that amounts to 22.5 watts diss, so it 
will work ok.
But 10 ohms doesnt limit the fault current to a low value.  2600 divided by 
10 = 260 A fault current,
which is still a bunch.   2600  divided by 50 ohms = 52 A fault 
current..which is a lot less obviously.
Anything is better than nothing of course.

##  Forgot to mention in my previous posts, re protection diodes.  I use 
several 6A10 s in parallel, to
make one big diode.   3 or 4 of the 6A10s, each with a 400A  surge rating, 
albeit only for 8.3 msecs,
is then good for  1200-1600A.   With out any HV fuse in there to interurpt 
the fault current, it can take
a while for the breaker in the 240 vac line  to open up.   The HV filter C, 
plus the value of the glitch Resistor,
form a simple  RC network.

##  eg.  25uf  and  10 ohms  =  .00025 secs.   = .25 msec
25 uf and 50 ohms =  .00125 secs     = 1.25 msecs
100 uf  and  50 ohms =  .005 secs     =  5 msecs

## and thats just the time it takes to partially discharge the filter cap 
down to just 36.8 % of the original B+ voltage.

Jim  VE7RF
_______________________________________________
Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps