[Amps] 3-500Z glitch resistor

[sccook1 at cox.net]

One more comment...

On my 8170 amp I used a 20 Ohm, 25 Watt wirewound.  When I first got my amp working, I had made a mistake in the neturalizing circuit and the amp was not fully neturalized and would bo BANG!!! during the tune up procedure.  BANG!!! as in 12 Ga. shotgun loud BANG!!!

I got the neturalization problem solved, but not before I went through 5 or 6 20 Ohm, 25 Watt wirewould resistors (in series with the B+).

Each time the loud noice shook my world, the resistor opened and removed the B+ from the tube.  The only collateral damage was to the Screen Regulator crowbar SCR.  Never hurt a diode in the B+ supply or anything else.

If I had used a fuse in series with the resistor, I would have been replacing fuses instead of the harder and more expensive wire wound resistors.  Probably would still killed the SCR though.

There, I said it.  I am all done now...

-S

---- David Cutter <d.cutter at ntlworld.com> wrote: 
> Glass tubes are not so easy to find: some plastics might do just as well 
> filled with sand.
> 
> David
> G3UNA
> 
> ----- Original Message ----- 
> From: "Roger (K8RI)" <sub1 at rogerhalstead.com>
> To: "Peter Voelpel" <df3kv at t-online.de>
> Cc: <amps at contesting.com>
> Sent: Tuesday, September 16, 2008 10:27 PM
> Subject: Re: [Amps] 3-500Z glitch resistor
> 
> 
> > Peter Voelpel wrote:
> >> Put the wire into a glass tube and fill that with sand
> >>
> >
> > Now that makes sense. Basically a HV fuse is just a tube with a wire
> > filled with sand.
> > If glass just make the diameter large enough to handle the pressure.
> >
> > 73
> >
> > Roger (K8RI)
> >> 73
> >> Peter
> >>
> >> -----Original Message-----
> >> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
> >> Behalf Of Roger (K8RI)
> >> Sent: Dienstag, 16. September 2008 20:10
> >> To: Kevin LaHaie
> >> Cc: amps at contesting.com
> >> Subject: Re: [Amps] 3-500Z glitch resistor
> >>
> >> Kevin LaHaie wrote:
> >>
> >>> Harbach recommends a single strand of #32 or 36 wire create a fusible
> >>>
> >>>
> >>
> >> I really don't like the thought of a piece of wire in there long enough
> >> to extinguish the arc, or to coat things with vaporized copper. OTOH
> >> using regular fuses is inviting disaster. Most are rated no more than
> >> 250 v.  HV fuses are difficult to find but about the only safe way to go.
> >>
> >> 73
> >>
> >> Roger (K8RI)
> >>
> >>> link, in series with the current limiting resistor.  Makes sense -
> >>> inexpensive with big potential returns!  A recommended source of this
> >>> wire being a single strand from a computer disk drive ribbon cable - we
> >>> all have those lying around!
> >>>
> >>> 73 Kevin K7ZS
> >>>
> >>> sccook1 at cox.net wrote:
> >>>
> >>>
> >>>> Team,
> >>>>
> >>>> How about a resistor in series with fuse.
> >>>>
> >>>> -S
> >>>>
> >>>>
> >>>>
> >>>>
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> >>>
> >>>
> >>>
> >>
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