Re: sparks running down secondary - why?

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

Original poster: "Paul Arrowsmith by way of Terry Fritz <twftesla-at-qwest-dot-net>" <p_t_arrowsmith-at-hotmail-dot-com>


Sound like the primary and secondary are over coupled causing excessive 
mutual inductance, try raising the secondary to make greater separation to 
the primary turns lowering the coefficient of coupling.

Paul A

>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: sparks running down secondary - why?
>Date: Mon, 28 May 2001 14:09:47 -0600
>
>Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><vanyo-at-echoes-dot-net>
>
>Last time I ran my coil, I got occasional loud snappy sparks running
>down the length of the secondary, as well as occasional firing of my
>safety gap.  Wondering what causes the sparks down the secondary, and if
>it's a problem?
>
>The only change I made since my previous run (which was still
>underperforming, but perhaps due to wind - not sure - this is my first
>coil) was to hook my NST power supply (three 15/60's, two with internal
>PFC) to a seperate 20 amp line.  I could now run it without tripping the
>breaker.  I still plan on hooking it to a 30 amp 240 volt line, stepped
>down by variac to 120 volt.
>
>Oh, and the other change is a bigger topload.  Originally, I had a
>smaller toroid, and now have added a larger one on top.  I can run with
>just the larger.
>
>	Thanks again,
>	Bill V.
>
>Specs again:
>
>Power Supply: Three 15/60 NST's (two have internal PFC), with Terry's
>protection filter on the
>high voltage side, and redundant line filters and a 50 amp variac on the
>120V side.
>
>Capacitor: A Maxwell 30 kV, 0.06 uF cap (model # 37321).
>
>Static Spark Gap:  9 copper pipes mounted in a blower box, with
>adjustable spacing.
>
>Secondary: 1000 turns of 22 awg, 6.5" (closer to 6 5/8) diameter, 27.5"
>winding length.  Countless coats of polyurethane.
>
>Primary (just rebuilt): Flat spiral, 10 turns of 1/4" copper tube, 1/2"
>spacing on centers.  Inside diameter 9.5".  Tapped between 6 and 7
>turns.
>
>Toroid: I have two toroids, both aluminum dryer duct, and constructed
>so  I can easily attach either or both.  The smaller is 6 inch cord with
>14 inch center to center spacing, and the larger is 8 inch cord with 24
>inch center to center spacing.
>
>Ground: 32" segment of copper clad iron ground rod.
>
>
>

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