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Success, Then a Cap quit

 * Carbons Sent to: oldradio-at-cheney-dot-net
                    tesla-at-grendel.objinc-dot-com

Quoting Jim Watson <oldradio-at-cheney-dot-net>:

> I got the small coil that I built up and running today, at 
> least for a time.  The secondary is 4.25" in diameter.  The 
> toroid consists of a 10" aluminum disk with 3" aluminum tubing
> (16" diameter overall).  The primary is thirteen turns of 3/8"
> tubing spaced 3/8" apart, at a 30 degree angle;  I used 11 of 
> these turns to get the coil tuned properly.  The input is a 
> 15kV-at-30mA neon sign transformer.  Once I got it tuned nicely, 
> it was putting out arcs approximately 20 - 24" long 
> consistently;  at times there were longer arcs, but not 
> consistently.  I was tweeking the tuning when the .005uF 
> capacitor that I made failed.  I guess that I will find the 
> cause when I rebuild it.

Air. A common cause of failure on a new homemade cap that had not
been allowed sufficient break in time. After the dielectric
failed you will not find any specific cause upon disassembly.
Everything around the puncture will be well carbonized.

> Would you consider the arc length typical, or should I be able
> to get longer arcs?

What! You are reporting 20" - 2 feet and you are thinking you
should be getting more! I felt lucky to be able to light low
pressure tubes from my first firing of a real coil system. The
next step was drawing 2" of spark off with a grounded rod. Rest
assured, you are doing quite well! Keep it up!

> Another thing you might find interesting is the rotary gap for
> the large coil that I am building.  A good friend of mine named
> Carlos Carey, who is a retired machinist, built it for me.  It
> consists of a 10,000rpm universal motor coupled to a 10" diam.
> disk through a bearing supported shaft.  The disk has eight 
> tungsten electrodes.  I have had the wheel up to 6,000rpm for 
> short periods of time, and there was no detectable vibration. 
> I'm afraid that if I turn it much faster the wheel will come 
> apart.  The good thing about it is that it is variable speed 
> from 0 rpm to 10,000 rpm (if I had guts enough to take it that
> high).

Sounds nice... I am having to re-work my large rotary due to
imbalances caused by a "self balancing" pulley that sprung. It
will be some days before I can put my variable speed rotor back
on line.

> I have taken a number of pictures, and will email copies to you
> after the big coil is finished (about another week), if you 
> wish.

We all like to see coil photos, and most of us like getting the
files E-Mailed on the net. Send the images in JPEG format to Chip
and we can all see them.

Richard Quick

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