Re: mmc question.... still working on first light.

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi,

At 10:51 AM 9/1/00 -0400, you wrote:
>mmc stats:
> 8 strings    
>3 caps per string
>6.5kvdc. per cap
>.015mfd +-10%  per cap
>
>i mounted the caps on a 3/4" piece of wood  is this a bad idea???  i have 
>recently read that wood isn't a very good insulator at high voltages.   

If the wood is really dry or the high voltage terminals do not come into
contact with the wood, you will probably be ok.  I would not recommend wood
but it can be done..

>I 
>have yet to get first light out of my coil and this seems to be the problem.  
>the reason that i am suspecting the mmc is because i tried to charge it the 
>other day with a bank of 3 mot's and i had no luck at all.   i hooked the 
>mot's secondaries in series across the mmc and charged it for a few seconds 
>then  tried to short it out and nothing happened.  any ideas as to what might 
>be going on???  

First, I assume the MOTS are wired correctly in phase so their voltages all
add rather then subtract.

The voltage is AC so the voltage left on the caps will be the voltage when
you pulled to plug.  It is possible you hit the low voltage part of the AC
waveform.

If you had the MOTs directly wired to the cap and pulled the plug.  The
caps would immediately discharge back through the resistance of the MOT's
windings.

The wood will probably dicharge the caps in a few seconds to minutes...
  
> 
>coil sats...
>
>6" secondary  
>22ga wire 
>23" of wraps on the secondary
>8 turn primary
>1  1/2" between turns (aprox)
>3 mot's in series  
>assuming 2500v per mot. 
> i don't have a meter capable of testing over 1000v ac 
>i have tried using a 4th mot with the secondary winding unconnected (not 
>shorted) as current limiting (placed in series with input power from the wall 
>socket) but i was unable to get any spark (maybe 1 mm at most)   should i 
>have placed the current limiting mot in series with the OUTPUT   of the 3 
>mot's ??   

The current limiting alwasy goes on the input.  Carefully check the wiring
of the MOT secondaries (primaries too),  Sounds like something is either
backwards or miswired. 

>should i have the secondary windings on this mot shorted? 

The current draw will normally blow a fuse.  Do you have the input AC of
the MOTs wired in series or parralel?

Cheers,

	Terry
 

>  terry was helping me with all these problems a few weeks ago and i jsut got 
>around to some more experimentation (with no luck)    any info would be 
>greatly appreciated 
>
>