[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Terry filter alternates?

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

At 05:26 PM 12/3/2004, you wrote: 
"Hi Black Moon,

I think you will roast those 10W resistors.  On my old 6" coil the 1K
50W
resistors would get really hot at the 12/120 power level.

David E Weiss"

        0.12^2*1000 = 14.4 watts (IF I didn't slip a decimal point.)

What was the real current in those resistors?  Can't be very far from
sinusoidal with all of the leakage reactance.

Ed 


You are also discharging the filter caps each time the gap shorts.

http://hot-streamer.com/TeslaCoils/MyPapers/modact/Image165.gif

300pF at 21kV 120BPS....

E = 1/2 C V^2 x BPS = 29 watts!!

So we now have 43.4 watts in the resistors. At 100 watts, they have a 300C temp rise. At 43 watts, they are cooking at 155C Darn toasty!!

Problem is the normal full rated temp for the power resistors is stunning 300C!! So we massively over rate them to keep the temperatures sane. Originally I used much smaller resistors, but everyone whined that they were getting supper hot. So I upped the size of the resistors like 4X and no more complaints ;-))

Cheers,

        Terry