Re: Tesla coil specs.
Subject: Re: Tesla coil specs.
From: Bert Pool <nikki-at-fastlane-dot-net>
Date: Mon, 01 Apr 1996 20:30:12 -0500
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At 09:02 AM 4/1/96 +0700, you wrote:
>>From mrbarton-at-ix-dot-netcom-dot-com Sat Mar 30 07:12 MST 1996
>>My last coil was finished January '95. Secondary is 16 inches in diameter,
>>4 foot coil length, teflon insulated stranded wire, 22 gauge (about 3,000
>>ft). Primary is a 4 foot diameter flat spiral monster using 1+ inch
>>diameter coax. Toroid is 62 inch diameter, 7 inch chord. I got a very
>>disappointing 6 foot discharge with a 15 kva pole pig, 14.4 kv. I'm
>>rewinding the secondary with 10 gauge enamel, and will try it again with
>>better caps (last time I used some questionable pulse discharge caps which
>>were very lossy at Tesla coil freqs). Caps which are rated at 800 pulses
>>per second just don't work well when you use them in a resonant circuit at
>>approx. 100 khz or less!
>Don't rewind that coil! I have gotten 18 foot discharges from a coil wound
>with 22 gauge wire and a smaller transformer. Going to thicker wire will
>just raise your resonant frequency which is something you don't want.
>Don't use coax for your primary. Switch to copper tubing.
>Better caps are always a nice idea.
The primary I wound is wound with what I loosely call 'coax'. A friend of
mine liberated a couple hundred feet of H.V. cable designed to be buried.
It has a solid aluminum outer jacket of soft aluminum (it is NOT braided).
Since this is technically a "coax" cable, that's how I always refer to it.
It is in effect an aluminum pipe 1 inch in diameter covered with poly. It
makes a great primary!
I understand that changing over to 10 gauge enamel will (1) lower inductance
and (2) raise operating frequency, but I have discovered that larger gauge
wire can make up the difference. What I will do, based upon your advice, is
to retry this coil with good primary capacitors before I rewind it.
Would you describe in detail your coil and system that produced 18 foot arcs?