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

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

Original poster: "Mccauley, Daniel H by way of Terry Fritz <twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>


Actually, this is completely wrong.  Although "some" power resistors can
heat to the point where they glow red, there are a large number of power
resistors which CANNOT take these type of temperatures.

Also, although a resistor may be able to take 350C, the components or
enclosure around it may not.  For example, 350C will definitely damage a
FR-4 board and unsolder nearby components.

Dan



Hi Larry,

Power resistors are basically space heaters.  At full power they can run
350C or slightly glowing hot!  I use much larger power resistors than
needed to keep the temp fairly sane but they will still get hot for sure.
The heating you see is perfectly normal.

Cheers,

	Terry
 

At 01:25 AM 9/18/2002 +0000, you wrote:
>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.
>
>