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Re: Safety gap and first light

to: Bill

It may be to high, but if you don't have enough turns on you will never
know.  If you have too many, no problem --- just tap at the point of best
resonance, but if you have to few you could be switching caps and fiddling
with everything and never discover the problem.  Too many is always good to
start with --- make it look nice AFTER you have found the best resonance by
replacing with copper tubing, strap, etc with the correct number of turns
plus approx 1-2 additional.

Glad you discovered your wiring error.  Did you do your cap under vacuum
(evacuate and fill with oil)?  If not, then an air bubble probably got it.

Regards,

Dr.Resonance

-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Saturday, June 12, 1999 7:54 PM
Subject: Re: Safety gap and first light


>Original Poster: Bill Fuller <wfuller-at-home-dot-com>
>
>Dr. Resonance,
>
>Well it turns out that part of the problem was operator error. I had wired
the
>spark gap in series with the cap and primary like this: NST output-spark
>gap-cap-primary coil-NST output. After connecting the NST across the spark
gap
>everything changed!!!! I immediately got 15" streamers from several points
on
>the toroid. The safety gap on the cap was still firing quite a bit so I
tried
>some tuning and improved things a little. Since I couldn't get the variac
above
>~60 volts without the safety gap firing I figured I could move the safety
gap
>to 1" and increase the voltage. At about 80 volts I BLEW THE CAP! BIG
lesson
>learned.... The cap safety gap IS NEEDED. I'm using a single cap with 1/16"
>LDPE layers. I had been cautioned by several posts in the past about rating
the
>cap too aggressively but excitement got the best of me. Dis-assembly
revealed a
>1/4" hole clean through the LDPE.
>
>Question:
>You mentioned going to 22-24 turns. Tesla Designer calculates  ~140 KHZ for
the
>toroid/secondary, 120 KHz for the cap/primary with 12 turns (140 KHZ at
10.5
>turns). 22-24 turns seems way too high?
>
>Thanks for the Help,
>
>Bill
>
>
>
>Tesla List wrote:
>
>> Original Poster: "Dr. Resonance" <Dr.Resonance-at-next-wave-dot-net>
>>
>> to: Bill
>>
>> Not enough primary for initial test with this large toroid.  Use some
scrap
>> 12 AWG wire and 22-24 total turns.  Tap as necessary until you find the
>> resonant point.   Go back to the pretty copper tubing later --- after it
>> works.
>>
>> Regards,
>>
>> Dr.Resonance
>>
>> -----Original Message-----
>> From: Tesla List <tesla-at-pupman-dot-com>
>> To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
>> Date: Friday, June 11, 1999 3:29 PM
>> Subject: Safty cap and first light
>>
>> >Original Poster: Bill Fuller <wfuller-at-home-dot-com>
>> >
>> >Well, after many months of seaching for parts and construction, I fired
>> >up my coil last night for the first time. No arcs!  I'm not sure where I
>> >got the idea, but I have a safety gap across the primary cap (~0.6"). As
>> >soon as my RQ air blast gap starts to fire(90v on the variac), so does
>> >the safety gap. The RQ gap is set at 0.3".  No amount of tuning fixes
>> >the problem. I did a search in the list archives and it seems unclear if
>> >this safety gap is needed. (I already have a safety gap and RC filter on
>> >the NST's). Any idea's?  Here's the coil spec's:
>> >
>> >15KV NST's at 90 mA (plan to use 150mA)
>> >8" dia secondary 32" long 19 ga wire (29mH)
>> >28" x 7" toroid
>> >Flat plate primary cap 0.026 uF
>> >10 deg. primary inductor 12 turns 1/4 tubing, 1/4" spacing (66uH)
>> >
>> >I know the cap is on the large side for 90 mA. I don't think this is an
>> >issue though.
>> >
>> >Thanks for your help, can't wait to get back to it tomorrow!
>> >
>> >Bill Fuller
>> >
>> >
>
>