Re: Toob coil questions

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

Tesla list wrote:
 >
 > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
 >
 > Hi Steve,
 >
 > At 10:26 PM 9/18/2003 -0500, you wrote:
 > >Hi Terry!
 > >
 > >I will answer as many of these questions as i can ;)
 > >
 > >
 > >>From: "Tesla list" <tesla-at-pupman-dot-com>
 > >>To: tesla-at-pupman-dot-com
 > >>Subject: Toob coil questions
 > >>Date: Thu, 18 Sep 2003 19:12:46 -0600
 > >>
 > >>Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
 > >>
 > >>Hi All,
 > >>
 > >>I may be an expert on some Tesla coil things, but not toobs 0:-p
 > >>
 > >>So I got this tube coil off E-bay that is really cool!!  Makes 16+ inch
 > >>sparks!
 > >
 > >16" is a LOT from a pair of 811As... the coil may be designed to drive the
 > >tubes far beyond their ratings... You better watch that the pates DO NOT
 > >get even a bit of color on them.  If they turn red at all, you are pushing
 > >things hard!
 >
 > Oh!!  I did note that the red hot area was sort of a concentrated hot
 > spot...  Thanks!!  Now I know what I am seeing is real and scarry...

	That criterion is a little conservative.  Operating 811's or 812's with
a red or even orange spot in the middle of the plate isn't going to
destroy the tubes if you don't run them for more than a few minutes at a
time.  I've run a pair in a ham transmitter with the plates showing a
definite orange in the center and never experienced failures.

Ed