Re: CD 942 failure tonight

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

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi John and All,

I looks at John's video and caps:

http://hot-streamer-dot-com/temp/P3070026.jpg

There is just a big hole in both about 3/16 inch deep.  It looks like it 
just exploded...  There is not enough energy in a single cap to do that so 
I don't know where all the energy came from.  There was no other arcing 
inside.  It just looks like it got a single high energy over voltage that 
blew a big hole in the cap.  Apparently John does not have the strings 
cross connected or anything like that.

I think he should set his safety gaps like this:

http://www.pupman-dot-com/listarchives/2000/January/msg00044.html

The resistors were very well attached, far from the cap, and checked out 
fine.  So I don't see any obvious cause.

There is a small chance the big 12/120 NST Transco is saturating the shunts 
and maybe putting out too much voltage/current but I have never seen that 
before with a LTR rotary.

One thing that does worry me.  He has his primary far away from the cap, 
NST and all.  They are hooked up with about 6 feet of wiring.  I wonder if 
that long primary wire's inductance is doing something odd and causing high 
voltages back on the caps or something?  I am not sure if that would do 
something bad or not.

So I don't know what is going on really :-(  but something sure is 
strange.  He says the primary gets hot and the cap are heating some.  I'll 
grind the cap through the center tomorrow and see if there is heat damage.

Cheers,

	Terry