Marv,
Peter,
Ian,
Ken,
Thanks for the replies. It seems as if the OE5 circuit is in active
service and should do the job. I will start collecting parts - the
thyristors at least.
As to the triggering, I will build a (low voltage) test rig and try
the transformer method. I like the look of its simplicity and am
curious to discover whether only a little processing of the (glitch)
current as detected in a low value resistor in the HV- (or even the
'glitch' resistor in the HV+) would suffice - KISS!
Marv, I would like a copy of the schematic for your crowbar. It all
adds to the knowledge base!
Regards.
Mark.
-------------------------------------------
At 03:25 21/07/2006, you wrote:
>Hi Mark,
> I designed one of those for use with a 3KV 1A supply that contains a
>40uF output cap.
>
> I did build the crowbar section but, the rest of the supply is
>incomplete at present so, it hasn't been tested.
>
> I can send you a schematic if you wish.
>
>73 & Good evening,
> Marv WC6W
>
>http://wc6w.50webs.com/
>
>***************************************
>
>-- Mark Hill <g4fph@mjha.co.uk> wrote:
>Folks,
>
>Talking of protection. I'm contemplating building an crowbar for the
>HV supply in my 3CX3000A7 PA.
>
>The PSU filter capacitor is really too large (130 uF) and the amount
>of energy it holds when charged to 5 kV is frankly scary. Eimac's
>AB17 seems unclear about how much of a bang this valve can take (4J;
>50J; something in-between?). I'm not sure whether my ear drums would
>be OK under conditions of flash over either!
>
>I found an interesting article here:
>http://www.astec.ac.uk/rf/rf_preprints.htm (a little way down the
>page there is a PDF file entitled, 'A Solid State Crowbar for RF Tube
>Protection').
>
>I like the way that the series thyristor combination appears to have
>been driven, i.e. individual current transformer for each device with
>a common primary turn through them all. Has anyone tried this
>technique? Seems as if it might be cheaper and potentially more
>reliable than a bunch of opto couplers and transistors etc. Is
>anyone on the line using a crowbar of any description?
>
>Regards.
>
>Mark.
>*******************************************
>Mark Hill - G4FPH
>E-mail: g4fph@mjha.co.uk
>Current web pages at: www.g4fph.net
>Old web pages at: www.qsl.net/g4fph
>----------------------------------------------------------------------
>Dipoles resonant on 1942 / 3720 / 7085 kHz
>Three element wire beam coming soon on 14180 kHz!
>----------------------------------------------------------------------
>Remember - SIDE for HV safety:
>S witch off
>I solate
>D ump
>E arth
>*******************************************
>
>
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>
>
>
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*******************************************
Mark Hill - G4FPH
E-mail: g4fph@mjha.co.uk
Current web pages at: www.g4fph.net
Old web pages at: www.qsl.net/g4fph
----------------------------------------------------------------------
Dipoles resonant on 1942 / 3720 / 7085 kHz
Three element wire beam coming soon on 14180 kHz!
----------------------------------------------------------------------
Remember - SIDE for HV safety:
S witch off
I solate
D ump
E arth
*******************************************
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
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