Re: glass vacume gaps

Subject:  Re: glass vacume gaps
  Date:   Thu, 17 Apr 1997 00:07:36 -0400
  From:   104521.363-at-compuserve-dot-com
    To:   tesla-at-pupman-dot-com 

Subject:  Re: glass vacume gaps
  Date:   Tue, 15 Apr 1997 12:41:32 -0400 (EDT)
  From:   DavidF4797-at-aol-dot-com
    To:   tesla-at-pupman-dot-com

In a message dated 97-04-05 05:23:38 EST, you write:

> I don't mean to rain on your parade, but how is the considerable heat 
>  buildup of the gap electrodes going to be removed if they are sealed 
>  in a glass enclosure?  I'd worry about that unless the coil is just a 
>  5 or 10 watt job.
Without getting too far off tc stuff, in medical applications, the x-ray
tubes come with an extensive tabular listing of peak cathode kv, current
amperage, pulse length and rate versus cool-down time till next usage. 
safety of these tubes (including cool down rates) are govt. controlled.

To help keep x-ray tubes cool, they are often enclosed in an x-ray
transparent, non-conducting cooling oil envelope with expansion bellows
and the like. Additionally, the anode of the x-ray tube is often a large
disk which is embeded onto the shaft of an induction motor.  The motor
turns the anode (2-3" in diameter) extremely rapidly so that only a
small sector at the edge of the anode disk is actually being
electron-stream bombarded and heated.  The motor, the anode shaft and
the anode are all encased in the x-ray glass/ceramic envelope which is
enclosed in the cooling oil blanket which is inturn enclosed in a larger
container.  These things are hefty. They draw off three phase supplies
and often use power tetrodes for independent voltage and current

Moreover, compared to all the power tubes used for high voltage
switching, these monsters have some of the highest breakdown voltages
(but relatively low currents) so they wouldn't make a good power triode
for a tube tesla coil.