Something additional thoughts and a question:
Circuit interrupters (fuses, circuit breakers, etc.) limit fault *duration*
only. This is true unless a fairly expensive class of "current limiting
fuse" is employed, where the melting / arcing time is kept within the first
1/2 cycle.
Series R limits maximum fault current. However, this current may sustain a
fault until the stored energy is gone or the circuit is interrupted, thus
causing additional damage. Obviously, higher series R would minimize fault
current damage, however the trade-off of reduced voltage regulation would
result.
So it appears that optimally, both current limiting and reasonably fast
current interruption would be required for good protection. My question is,
what is practical as an interrupting device between the tube and the high
voltage power supply?
Thanks es 73,
Jeff - K1LE - CT ><>
----- Original Message -----
From: "Conrad Farlow" <conrad@g0ruz.net>
To: "AMPS" <amps@contesting.com>
Sent: Tuesday, July 01, 2003 7:43 PM
Subject: RE: [Amps] 2500 uF at 450V DC for $10.00 each
> Yes but lots of joules are really bad when you are trying to interrupt a
> power supply that is arcing over in the event of a flashover, and we all
> know that this can, and does happen. The purpose of a series glitch
resistor
> in an HT supply is to limit the max fault current, the last thing you want
> in this scenario is lots of stored energy when the HT primary trip is
> activated, the result is usually a fried glitch resistor and/or a fried
> tube, this is why reputable manufacturers quote recommended maximum
> permitted energy levels allowed to flow during a plate flashover. Having
> lots of capacitance is a bad idea, this is not an original idea by me of
> course, it has been commented on many times on this reflector. In fact
this
> reflector is exactly where I learned of it.
>
> Regards
>
> Conrad
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]On
> Behalf Of Brian Carling
> Sent: 30 June 2003 13:11
> To: AMPS
> Subject: RE: [Amps] 2500 uF at 450V DC for $10.00 each
>
>
> ??
>
> Joules are good if you are converting them to RF.
>
> On 29 Jun 2003 at 17:43, Conrad Farlow wrote:
>
> > Put 10 in series and you have a whole lot of joules to deal with in
> > the event of a flashover, bad idea IMO.
> >
> > Conrad G0RUZ
> >
> > FOR SALE:
> >
> > ELECTROLYTIC CAPACITORS
> >
> > 2500 uF at 450V new, top-grade caps.
> > Cornell-Dubilier 400c series.
> > 4" tall, 2" diameter.
> >
> > Put 10 in series and you have 250 uF at 4500V DC
> > Put 20 in series and you have 125 uF at 9000V DC
> >
> > Pricing:
> > QTY 20 or above at $10.00 each
> > QTY 10 or above at $12.00 each
> > QTY <10 at $15.00 each
> >
> > Shipping Additional
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
>
>
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