[Amps] 3CX800 and blower

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Mon, 7 Sep 2009 10:26:42 -0400, "David J Windisch" <davidjw at cinci.rr.com>
wrote:

>Does a 3CX800A7 require airflow any time the filament is lit, like, say, 3-500Z glass tubes with tender seals and 70-watt filaments?
>
>I'm thinking of leaving the (unobtanium) blower turned off, to lower wear and tear, until I need the power.  
>
>Yep, I'm aware of the potential hazard of a senior moment: I have in mind a no-blower-no-operate interlock scheme.

REPLY:

Personally, I would not risk it with such an expensive tube. The answer to your
question, and the only way to be sure is to measure the temperature of the
metal-to-creamic seals and make sure they do not exceed 250 degrees C. 

As the data sheet says:  "It should also be noted that it is not good practice
to operate at, or close to, the absolute maximum temperature rating for the
metal/ceramic seals. Where long life and consistent performance are factors
cooling in excess of normal requirements is normally beneficial."

Words for the wise.

73, Bill W6WRT