RE: terry's nst filter:power res overheating?

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

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

For power resistors, 120 F is nothing!  If you can touch them without
smelling burnt skin, they're all right.

Of greater concern is the width of your main gap.  Power throughput,
performance, and consequently, power through the resistors, will all
increase as the gap width increases.  But so does the voltage that your NST
and Cap sees.  1/2" is much too wide for a 12kV NST.  My 15kV NST runs with
a 0.25-0.30" gap width.  Assuming the main gap is wired across the NST, the
width should be set by adjusting it to just fire when the primary tap is
disconnected.  Reducing your gap width will diminish performance, but your
NST and cap will live much longer.

Regards, Gary Lau
MA, USA

>I wired the unit up tonight.  less interferrence than the choke filters i 
>was using. coil output seems slightly better.  but the problem is the power 
>resistors are heating up a bit more than I would like.  I am using
>2 12kv 30ma nsts.  my gap is way maxxed out at somewhere just under 1/2".  
>I'm assuming that the gap being wider than it should is probably causing 
>overheating. the power resistors after 10mins of testing were about 110-120 
>degrees F.  the safety gap fires occasionally. any ideas?
>I could post a link to a picture of the board plus the wiring layout i 
>chose.  none of the other components are showing any signs of heating.  what 
>is the limit of the heating of the power resistors? perhaps 150F ?
>am i just overreacting?
>
>larry.
>
>