> From: Rich Measures <measures@vc.net>
To: <amps@contesting.com>
> Date: Tue, 15 Jul 97 02:45:51 +0000
Ian wrote:
> >Two further things come to mind.
> >
> >One was the message from Reid Brandon at Eimac, posted a few weeks ago
> >by W0UN. Here's the currently relevant part:
> >
> >>Tungsten wire undergoes a physical change when raised to its
> >>operating temperature and returned back to room temperature.
> >>In tubes with thoriated tungsten filaments, the end result is that
> >>over many on/off cycles the shape of the filament begins to become
> >>distorted, ever so slightly but depending on how many cycles, the
> >>spacing between the filament and grid (which must be very close to
> >>achieve good electrical characteristics) may decrease, and eventually
> >>a short may occur.... Reducing the filament inrush current
> >>is no solution, tungsten must still go through a large excursion in
> >>temperature.
Rich then posted:
> Eimac's engineering department presumably decided that it was best to
> limit the 3-500Z's filament inrush current to double the normal 14.5A.
> As of December, 1996, Reid Brandon did not work in in the engineering
> department. He worked in the marketing department.
Rich, why is it when someone disagrees with your "theories", you
always imply they are unworthy or have personal motives?
> straight. However, in a centrifuge we were able to do the job in 30 to
> 40 seconds.
Riding around with 3-500Z's in a clothes dryer is bound to make a
person sick.
73, Tom W8JI
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|