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Re: Can anyone diagnose problems with our coil? (fwd)
Original poster: List moderator <mod1@xxxxxxxxxx>
---------- Forwarded message ----------
Date: Mon, 11 Dec 2006 19:48:02 -0700
From: resonance <resonance@xxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Can anyone diagnose problems with our coil? (fwd)
You definitely want to install a "Terry Filter" between your neon
transformer and your sparkgap. If not, the kickbacks will quickly damage
your nst which it may already have done. Test for a hot spark to ground off
each bushing of the neon xmfr to be both sides are still working.
also, be sure to NOT connect the cap across the xmfr ---- the sparkgap
should be connected across the xmfr and the cap is hooked in SERIES with the
pri coil tap.
Use some scrap wire --- approx 20 turns --- to test tuning points to be sure
you are not just a few turns short of resonance. If you have too few turns
you will never know this --- but you just can not find the resonance point.
Probably need a 6 or 7 inch aluminum ball or home-made dryer duct tubing
covered with adhesive aluminum tape (both from Home Depot) for optimum
performance. You can use some 4 inch dryer duct tubing shaped into a torus
shape and cover with adhesive alum. tape.
> ---------- Forwarded message ----------
> Date: Mon, 11 Dec 2006 17:23:59 -0800
> From: chipford@xxxxxxxxxxxx
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Can anyone diagnose problems with our coil? (fwd)
> this is probably not great advice but..I have a small coil in my apartment
> that i ground with a sink full of water with a stainless steel ashtray
> submerged on one end connected to the bottom of my secondary on the
> other..I have achieves 20"-24" sparks w/(3) NST attached. 12-14" sparks w/
> (1) 15k30ma transformer.... The coil is a 3" secondary pvc w/22ga. wire
> Also, how much gap do you have. The cap seem large to me also...I'm new
> ---- Tesla list <tesla@xxxxxxxxxx> wrote:
>> Original poster: List moderator <mod1@xxxxxxxxxx>
>> ---------- Forwarded message ----------
>> Date: Mon, 11 Dec 2006 15:03:05 -0800
>> From: john welch <jowelch@xxxxxxxxxxxx>
>> To: tesla@xxxxxxxxxx
>> Subject: Can anyone diagnose problems with our coil?
>> My student assistants and I just built our first coil. It kind of works,
>> but we are getting little tiny streamers coming out from the top of the
>> secondary coil and nothing from the ball on top.
>> We have tuned the circuit fairly carefully so that their resonant f's
>> are very close. We have a multiple spark gap made of copper pipes. We're
>> using 2 Condenser Products pulse discharge caps in parallel to get .01
>> mF rated at 10,000V. We have a 6000V neon sign transformer. We are
>> grounding the secondary to a wall outlet ground - I've heard not to do
>> this, but am not sure why and can't find much else to do indoors, and
>> many people tell me that that's what they do. Our secondary coil is
>> 22ga magnet wire around 3" PVC. The top end of the 22ga wire is
>> connected to the ball, and the bottom end to a 5 foot length of 10 ga
>> wire that I stick in the "3rd prong" of an outlet. Our primary circuit
>> is the transformer directly across the spark gap, and the (cap and coil
>> in series) also across the spark gap. We plug the transformer into a
>> variac, and have both a line RF filter and a power factor capacitor.
>> Any advice would be greatly appreciated.
>> John Welch
>> Cabrillo College Physics Dept.