RE: Microwave Oven Caps

["Lau, Gary" <Gary.Lau-at-compaq-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Comments interspersed:

>Original poster: "Tom Stathes" <newphreak_16-at-yahoo-dot-com> 
>
>If i were to wire up all the caps in a box, and reopen
>the oil fillhole case of each cap, then fill the box
>with oil there should be no danger of explosion
>because pressure couldnt build up right? 

Probably correct, although I'm not familiar with the internal construction
of these caps.  But a more important issue (assuming they no longer explode)
is that microwave oven caps (MOCs) are designed for DC filtering at 60 Hz,
not high-current discharge applications.  Using such caps in a Tesla Coil
would give poor performance.  And equally if not more important, have you
considered the uF value you'd end up with?  Each MOC has a typical value of
1 uF.  For a 10nF final cap value, you'd have to series 100 of these.
That's a lot of ovens.

>Also, mabey you could help me out with this one. Or
>mabey you know someone who can.
>
>I just wound a new primary, its a flat spiral, 20
>turns, 1/4" steel guy wire spaced about 1/4" apart. 
>The inner diameter is 7.5" My secondary is 4.5"
>diameter and 20" high (902 turns) of #24.  The tank
>cap is ~10nf (wine bottles) and the tank input is 10kv
>-at- ~133ma.  
>I can't get corona discharge of no more than 7", my
>top load is a spheroid of about 5" diameter. The first
>turn of the secondary is 1 inch above the first turn
>of the primary. Whats wrong, why do i get almost no
>discharge? Should I adjust the coupling by lowering
>the secondary a little? (I have to cut a hole in the
>base of the primary to do this and i havent the time
>to do it yet.)  
>My less than spectacular other primary, (#12 wire
>wrapped on a old 12"  laundry detergent bucket
>(anything but even wire spacing)yielded sparks of up
>to 18". 

Steel is a very, very poor conductor when you need to pass hundreds of Amps,
and stranded steel is even worse.  You have to use copper, that's why your
#12 coil worked better.

Regards, Gary Lau
Waltham, MA USA