RE: Tesla Coil Theory into Practice Problem * clarify myslef*

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

Original poster: "Craig Shaffer by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bshaffer-at-coe.neu.edu>

Thanks for the posts...

As it would seem I haven't been all that clear.  It was late last night
when I gave up and decided to ask someone for help.  The X-ray
transformer is variable output via the auto transformer.  I usually run
it at 15 kv to simulate what other people are getting with their NST.  

	It is possible that the cap is toast but I don't see any arcing
inside and it does seem to hold a pretty nice charge.  The reason I said
I tested them one at a time was by doing the following.  I dissconnected
all the parallel connections (there are 3 caps) then I took them one at
a time out of the plastic tub they were in.  I connected the output of
the transformer to the terminals on the cap but I left one so that it
could be quickly dissconnected.  I turned on the juice for about 2
seconds dissconnected one side of the transformer then shut off the
power( this kept the secondary inside the transformer from draining the
cap).  I waited about 20 seconds and was able to draw a hot 1" arc by
shorting out the terminals.  I repeated this for the other three and saw
similar results.  

Is it possible that my total capacitance is WAY to small and that is
making the caps appear as though they are a short circuit???

Just to clarify this is how I have it hooked up


----Primary-----Cap----|------------|
|			  spark    transformer
|                     gap   	
|----------------------|-----------|
-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com] 
Sent: Wednesday, July 31, 2002 11:38 AM
To: tesla-at-pupman-dot-com
Subject: Re: Tesla Coil Theory into Practice Problem (Beginner)


Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<FutureT-at-aol-dot-com>

In a message dated 7/31/02 1:38:39 PM Eastern Daylight Time,
tesla-at-pupman-dot-com
writes:

Craig,

You can get away with the situation below by keeping your static gap
narrow enough so the firing voltage does not exceed 30kV, or whatever
voltage the capacitor can withstand.  If you're using two 0.060" poly
rolled caps in series, this can withstand the output from a 15/60 NST,
with resonant charging.  The same caps can withstand the x-ray
transformer output if the gaps are kept narrow enough to limit the
firing voltage to what would be produced by a 15/60 NST.  The use of a
too-wide gap, or a rotary gap may lead to cap failure in this
arrangement.

John


>
> If your X-ray transformer is putting out 40-60kV and your cap is rated

> 30kV, then your cap is probably toast.  Home-made rolled caps have 
> very ill-defined voltage ratings and even well constructed units will 
> fail under normal conditions.