The "industry standard" for such a resistor is a pulse rated R like a Kanthal
Globar. The company has changed names a lot recently, so search for them. These
are carborundum bulk resistors, non inductive. You can live with inductance of
a WW, of course, but in a dead short, you might find your resistor flashing
over with plasma. Then it isn't such a good resistor. Globar isn't cheap, but
they are excellent in this application, as well as for dummy loads. You have to
study their literature, type AS and SP material. One is better for continuous
dissipation and the other is best for very high peak voltages but low
dissipation. They make them with clip in connectors or wires.
73
John
K5PRO
> Message: 8
> Date: Wed, 17 Apr 2013 00:58:47 -0500
> From: donroden@hiwaay.net
> To: Amps@contesting.com
> Subject: Re: [Amps] HV resistor source
> Message-ID: <20130417005847.27844mn5ynlr261j@webmail.hiwaay.net>
> Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes";
> format="flowed"
>
> Quoting Jim Garland <4cx250b@miamioh.edu>:
>
> > That's going to be quite a resistor, inasmuch as 4KV across a 30 ohm
> > resistor amounts to a half million watts of dissipation! A 4KV pulse 50uS
> > wide, once per second, would dissipate 25W.
> > 73,
> > Jim W8ZR
>
>
> The resistor isn't to ground..... it's in series with the tube(s) that
> may draw 1 amp intermittently ... therefore 1 amp squared through 30
> ohms is 30 watts.
>
> If the tube draws more amps ... a short or a bad load... maybe a two
> amp spike... that is 120 watts which will hopefully burn out the
> resistor
> ( acting like a fuse ) before the transformer or diode stack goes up in smoke.
>
> Don W4DNR
>
> ***
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