Let me see if I have got lost here
Rich said
>Burning up a tetrode's screen from
>>>mistuning is unlikely because screen supply power transformers usually
>>>have fast-acting fuses in the primary.
>>>
Explain to me how this could be anyone only or primary protection against
screen overcurrent and be considered effective?
Ian G3SEK said
>>Can anyone think of a *worse* way to protect the screen of a tetrode?
>>
In my opinion I have to say an emphatic no!
Rich said
>>Substitute a 20A slow blow fuse for the fast blow screen fuse? Wrap
>>aluminum foil around an open fuse and reinsert in the screen fuse holder?
Sorry I stand corrected this is worse, well done Rich!
>>- During the entire time that the Plywood Box was in service, it
>>consumed less than 1 box of 5 fuses. Rated screen dissipation was 275w.
>>The fast blow fuse opened at roughly 200w.
That Rich is not a very scientific presentation of data is it?Are you saying
that because 5 fuses actually blew that this constitutes proof of "adequate"
protection?How roughly is roughly?Within 10 percent 74.35 percent
what?Mmmm.............
Rich then wrote
>>On AMPS, there are those who know what's what, and there are those who
>>pretend they know.
Could you please submit a list of those who know what's what and those who
don't Rich?Just so I know who to ignore.
Tom said
>Fuses mainly prevent drastic melt-downs.
Rich said rather usefully
>>[chortle]
Why is that funny?Are you still suggesting that a fuse in the primary of a
screen supply transformer is the "Best" protection?Cmon Rich you can back
down on this one and we won't hold it against you
Tom wrote
>Electronic circuits are
>much more reliable
Certainly more accurate and repeatable.
Rich wrote
>>Transistors that C/E short offer zero protection.
Ok so sense the voltage drop across a resistor across the screen supply,
feed the transistor via an opto isolator,make the transistor trip a fast
relay in the primary of the supply transformer.This is better and more
reliable than a fuse surely.
> and hundreds of times faster in most
>applications.
>>Screen potential was 1200 - 1500 V. Duhhh.
So what?
>>end
I doubt it!
Conrad G0RUZ
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