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Finishing First Coil
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From: Bert Hickman [SMTP:bert.hickman-at-aquila-dot-com]
Sent: Wednesday, June 03, 1998 6:38 AM
To: Tesla List
Subject: Re: Finishing First Coil
Tesla List wrote:
>
> ----------
> From: djQuecke [SMTP:djQuecke-at-worldnet.att-dot-net]
> Sent: Tuesday, June 02, 1998 6:58 AM
> To: Tesla List
> Subject: Finishing First Coil
>
> The closer I get to finishing the longer it takes <g>.
>
> A couple of Q's:
>
> 1. How closely must the chokes match? I've built two, one is 3.81mH and
> the other is 2.38mH. Is 2.38mH enough with a one or two NSTs (15kV,
> 30-60ma) so that I can simply derate the larger choke?
>
> Chokes are 22g on huge Flyback ferrites (mismatched ferrites resulted in the
> differing values).
Shouldn't be too critical, but matched sizes would be much bettter. Most
critical is insulating them from the core and end-to-end, since the
voltage developed across them can be considerable.
>
> 2. I need to verify grounding data. Just what gets hooked to signal ground
> and what needs a separate ground.
>
> a. NST has two input leads, two output leads. I currently have built
> the safety gap as two gaps between NST out leads and NST case. Schematics
> I've viewed indicate case should be connected to signal ground?
>
> b. What about NST input ground lead? (Actually I guess the question
> is: Should the ground lead on the NST input line be connected to the case (I
> don't think so), to signal ground (I don't think so), a separate ground
> (seems plausible) or don't connect it at all (seems strange to me but...).
>
> c. What ground should strike rail connect to?
>
The base of the resonator, center electrode of the safety gap,
strikerail, and the case of the NST's should all be tied to a good RF
ground which is separate from the AC Mains ground.
> 3. I see ton's of pix with coils running in garages. I can't imagine
> firing mine off in the garage (or in a kitchen as I've also seen). I have a
> rather crowded bench with electronic gear etc, flammables (paint, etc) and
> other misc. How far does the coil need to be from such gear? From a parked
> car?
Move the car out to prevent any damage to the paint, and move all
flammables beyond striking distance. You didn't say how large a coil
you're driving, but a 15 KV 60 MA source can easily provide 4 foot (or
longer) sparks on a well-designed system. Your garage door opener may
get toasted no matter what protective measures you use - simply
unplugging it will not prevent damage. This is especially true if it
takes a hit... :^)
>
> Should just be a matter of a day or two now (but I've been saying that for a
> week <g>).
>
> Thanks,
>
> dj
Good luck, and safe coilin' to you!
-- Bert --