[Amps] inexpensive HV fuse

[Carl]

Of course you could always employ the method detailed by John Lyles about 
instantaneously (almost) dumping the capacitor bank in a 500KW amp!

Carl
KM1H


----- Original Message ----- 
From: "Dave white" <mausoptik at btinternet.com>
To: "Alex Eban" <alexeban at gmail.com>; "'Angel Vilaseca'" 
<avilaseca at bluewin.ch>; <amps at contesting.com>
Sent: Wednesday, July 22, 2009 10:15 AM
Subject: Re: [Amps] inexpensive HV fuse


>I concur.....
>
> If you want to limit flashover damage use a high power surge limit 
> resistor in the HT line between capacitor stack and plate choke, and use a 
> fuse or overcurrent trip in the primary
>
> There was a circuit in Dubus by OE5JFL which used optoisolators and other 
> clever ideas to detect overcurrent and crowbar the ht away.  It seems a 
> bit overengineered to me but I've seen it work well.
>
> Like others are saying, fuses are too slow and you have no real idea of 
> how a spring will behave.  Remember how much the tube costs and spend a 
> few pennies on a surge resistor
>
> Cheers
> Dave G0OIL
>
> -----Original Message-----
> From: Alex Eban <alexeban at gmail.com>
> Sent: 22 July 2009 12:14
> To: 'Angel Vilaseca' <avilaseca at bluewin.ch>; amps at contesting.com
> Subject: Re: [Amps] inexpensive HV fuse
>
> Response time, guys!!!
> Any thermally operated fuse is TOO SLOW to protect the tube.
> Besides, the spring can carry many tens of Amperes before it heats up 
> enough
> to melt.
> You'll probably blow up diodes and tube and God only knows what else!
> Alex 4Z5KS
>
> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
> Behalf Of Angel Vilaseca
> Sent: Wednesday, July 22, 2009 9:21 AM
> To: amps at contesting.com
> Subject: [Amps] inexpensive HV fuse
>
> Commercially available HV fuses are quite expensive.
>
> I thought of using a small spring instead, like the ones in ball-point 
> pens
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps