Re: 8" coil :(

["by way of \"Terrell W. Fritz\" <terrellf-at-uswest-dot-net>" <CTCDW-at-aol-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

The data on Chris' coil:

Sec: 8" wound 29" with 20 ga
primary: 1/4" copper 1/2" c-c turn spacing, 11" ID 12 turns ( I had it tapped 
at the outermost turn)
bottom winding of sec is 3/4" below bottom of pri.
cap: .035uF -at- 20kv Mica pulse.....045 with my plasticcapacitors cap
60bps sync gap, which is very clearly out of phase, so that needs to be 
addressed. 
topload is 6 x 24" toroid

I wish there was some low power, non "violent" way to adjust the phase. I 
really don't like to have my safety gaps firing like that. I'm not willing to 
widen them yet, though, as the caps may not handle the overvoltage...that 
remains to be seen.

It is pig powered. I started at 1500 watts, which wasn't enough, and so I 
added an NST as additional ballast, whoch added about 400 watts to the pig, 
and did indeed help matters, so I think is is really a matter of enough power 
to drive this coil. I think between 3 and 4 kVA is where this is going, but I 
can't get that right now. THanks for any ideas!

Chris

>Hi Chris,
>
>We need to know some facts about your coil to 
>get it all tuned and stuff:
>
>What is the primary inner diameter?
>What is the center turn to center turn spacing of the primary windings?
>How many primary turns are available?
>Is the primary a cone shape and what is the angle?
>How high is the primary located off of the floor?
>What are the dimensions of the room the coil is in if it is faily "tight"?
>
>What size(s) of primary caps do you have?
>
>What is the secondary diameter and winding length?
>What wire guage or how many turns are there on the secondary?
>
>What are the critical dimensions of your top terminal?
>How far is it above the top turn of the secondary?
>How far is to bottom turn of the secondary above the inner turn of the
primary?
>
>What power sources do you have (NST, PIG, etc.)?
>
>What type of spark gap do you have?
>
>We can calculate anything but we need the critical numbers to punch in to 
>our equations...
>
>Probably just a tuning issue.  Sounds like you have all the "right stuff" 
>but it just needs to be adjusted...  Seems like the tuning is way off which 
>is easy to fix...
>
>Cheers,
>
>	Terry
>
>
>
>At 10:03 PM 7/19/00 -0400, you wrote:
>> 
>>Return-path: <CTCDW-at-aol-dot-com>
>>From: CTCDW-at-aol-dot-com
>>Full-name: CTCDW
>>Message-ID: <e4.7e32a87.26a7b6cb-at-aol-dot-com>
>>Date: Wed, 19 Jul 2000 21:58:35 EDT
>>Subject: 8" coil :(
>>To: FutureT-at-aol-dot-com, sgtporky-at-prodigy-dot-net, tonysasha-at-yahoo-dot-com,
>>	bwroblewski-at-yahoo-dot-com
>>MIME-Version: 1.0
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>>
>>Hello friends!
>>
>>Well, I tried it....2 measly inches, and an erratic sync gap. It is 
>>definitely sync though. so....
>>
>>.035- sync gap fires erratic...a few seconds firing, and a few not, BUT!!!!! 
>>the safety gaps did not fire!!! This is ballasted with a 1500 watt hair 
>>dryer. More capacitance? no.
>>
>>I added my .01 plasticcap in parallel for .045. Then the gap wouldn't
fire at 
>>all! still no safety gap activity.
>>
>>Decided to try my super duper almost no ballast at all choke transformer,
set 
>>pig to 7200V. nothing. changed to 14,400, and slowly turned up the
variac. at 
>>about 50%, the gap started to fire, and all three safety gaps went off. The 
>>neighbors must think I had been shot.
>>So then: Sync is out of phase, and its just waaaaaay too much power for this 
>>little 8" coil to handle. or my safety gaps are too close at 3/8" avg, with 
>>the pig gap at about an inch. I'm not willing to try this again until I have 
>>some real ballast on the piggy. If you have any life and cap saving ideas, 
>>please let me know.
>>
>>CHris