Re: MMC warming

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Steve,

At 11:11 PM 6/9/2002 -0500, you wrote:
>Hi,
>
>Im just wondering how warm do most MMC banks become.  Im looking for some 
>personal experience answers here.  

If the cases get to +15C over the air temperature, it is starting to get bad.

>I ask because my cap gets warm after a 
>bit of running.  I would say that my cap heats up to about 102 degrees(F). 

102 - 70 = 32F = 17.8C

So that is getting pretty hot.
 
>Off hand i do not know how many degrees C that is.  My GE caps are rated to 
>85 C.  I have a feeling that they are not that hot.  Im running my TC with a 
>reconditioned NST(12/40).  My cap consists of one string of 8, GE .068uf for 
>a cap of .0079uf -at- 24kvdc.  

The one string is probably running a bit over what it should be.  Keep the
runs short.  blowing air on the caps will help.

>I would have to say that my transformer primary 
>gets warmer than the cap, just to give you all an idea of the temperature.  
>I can hold my hand on the cap with absolutely no discomfort.  I hope that im 
>giving a good description of how warm they get.
>
>SOOOO... is this acceptable, or am i going to ruin these caps soon??  Ive 
>tried my next best cap configuration, 2 strings of 10 caps for a .0136 cap, 
>but this was much too big, and gave weak performance.

8.84nF for resonant and 13.9uF for LTR.  I would think your 2 x 10 array
would work just fine.  Maybe the tuning was off.

>
>Also, I was wondering what my perfomance would be considered(good or bad).  
>Heres my specs:
>
>12000v ~40ma NST
>9 gap static RQ type set at a tad bit over 12000v
>.0097 GE MMC
>Twin coil set up: pri, 3.5"inner/12"outer diameter, taped at 5 turns
>       Secondaries are 2.5"x 10" wound with 28g, 2"x12" toroids.
>
>My best spark so far is 26" with a breakout point, and 22" without a 
>breakout point.  Unfortunately, i could not get my SRSG to work.

1.7 x SQRT(12 x 40) = 37 inches   That is best case if everything is perfect. 

>
>I would like to hear what you all think about my MMC getting warm like it 
>does, because i really would like it to last a while.

I would work on getting the 2 x 10 array working.  Your present 1 x 8 may
last a while but it is under a lot of stress.

Cheers,

	Terry


>
>Steve Ward.
>