[Amps] Grid fuses (was: Life and gain of 3-500Z)

[Will Matney]

Chris,

The way I see it, it's the same, as that connection is in series with any anode fuse or glitch resistor. The way I also see it, if a tube starts to arc, it's gassy and needs to be replaced. So why let an arc continue possibly ruining the HV supply and having to repair it? If the resistor or fuse is sized correctly, it would tolerate regular operating grid current, and maybe a little over current from tuning, but blow open if it's excessive. I think this is what Rich means, I may be wrong. If we take say 3000 Vdc and placed it acorss a 30 ohm resistor, that would be a current flow of 100 amperes, am I correct? This across a 1/4 watt resistor?

Best,

Will

*********** REPLY SEPARATOR  ***********

On 7/21/06 at 9:09 AM Chris Howard wrote:

>On Fri, 2006-07-21 at 07:28, Tom W8JI wrote:
>
>> 2.) During an arc or anode to grid fault, the tube has 
>> plasma or significant leakage path inside. Opening the grid 
>> does not instantly make that plasma or path open. This is 
>> especially true when a very poor fuse like a small resistor 
>> is used to interrupt a few kV of voltage.
>
>sorry, I said I was going to quit.  
>But I really am learning from this exchange, so if you don't mind,
>one more question.
>
>Once there's an arc going, opening the circuit on the grid-to-ground
>side would have the same effect as opening the circuit on the
>HV-to-plate side... no?
>
>
>
>
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