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Re[2]: First light...Sort of

     First off, thanks to all who replied, the responses have all been very 
     helpful.
     
     My original specs. were off (I said they were from memory, and not a 
     very good one :)  Here are the correct specs:
     
     Power Supply:              15 kv NST, 60 ma
     
     Tank Cap:                  0.01 uF styrene
                                (4 x 0.04 uF, each with 2x20mil sheets
                                of styrene dielectric, stack caps in
                                oil bath)
     
     Primary:                   20 turn, 30 deg. inverted conical spiral
                                8.5" I.D, 25" O.D.
                                1/4" Cu Tubing, 1/4" Spacing
     
     Secondary:                 4.25" dia. x 54" long, close wound,
                                20 gauge (0.032" dia.) magnet wire,
                                1/8" wall PVC coil form
     
     Top Load:                  22" x 6" somewhat lumpy toroid
     
     Spark Gap:                 WAS (it died!) a RQ gap,
                                11 gaps -at- 0.02" ea.
     
     
     Since I made an enclosure for the RQ gap that includes a 1 HP vacuum 
     motor for cooling/quenching, I'm thinking about building a new RQ gap 
     with the same form factor.  I think I erred in using the same tube as 
     my secondary coil form as support for the RQ gap.  It's the 
     thin-walled, sickly-green PVC pipe used for low-pressure waste lines.  
     Has anyone had similar problems using the thick PVC?  Would the 
     chloronated PVC be a better choice.  What bonding method should be 
     used to join the Cu pipes to the PVC?  I used JB Weld (epoxy) followed 
     by Pop Rivets.
     
     What is another more heat-resistant material, available in a 4" OD 
     tube, that would be more suitable than PVC (excluding such 
     astronomically expensive options as phenolic and teflon tubes).  
     
     Aric
     
     


______________________________ Reply Separator
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Subject: RE: First light...Sort of
Author:  Tesla List <tesla-at-pupman-dot-com> at Internet
Date:    9/16/99 10:06 PM


Original Poster: "Lau, Gary" <Gary.Lau-at-compaq-dot-com> 
     
Hi Aric:
     
I think you did a good job of self-diagnosis.  By all means, chop down that 
secondary.  Even 30" is on the long side for a 4" secondary, 20-24" is more 
typical.
     
There's not enough info about your coil to tell if it is a tuning problem as 
well.  What wire diameter did you use on the secondary, and what is your 
primary inside-diameter?
     
Regards, Gary Lau
Waltham, MA USA
     
>Original Poster: Aric_C_Rothman-at-email.whirlpool-dot-com 
>I started up my complete coil for the first time, with disappointing 
>results.  Vital specs (from memory) are:
>
>Power Supply:      15 kV NST
>Tank Cap:          0.01 uF styrene
>                    (0.04 uF 40mil dielectric x 4 in series) 
>Primary:           18 turns, 30 degree inverted cone
>                  1/4" soft copper tubing, 1/4" spacing 
>Secondary:         4.125" dia. x 51" long secondary 
>Top Load:          4" x 32" toroid
>Spark Gap:         RQ style, 1/2" Cu tubing, 0.02" gaps, 10 gaps >
>First off, I know the secondary is way too long.  It was the first 
>part of the project I assembled and I didn't know what I was doing 
>(not that I do now ;)
>
> I tried several different tap locations on the primary, and managed to 
> get a few anemic purple sparks from the top load to the ceiling (about 
>1 foot).
>
>The PVC tubing around the RQ gap buckled, causing most of the gaps to 
> short out, once this happened, no further sparks from the top load 
>were produced.
>
>I'm going to build up a new gap, probably consisting of a series of Cu 
>tube section glued to a sheet of phenolic.
>
>As a first attempt to improve performance, should I slice out a 20" 
>section of the secondary and use that?
>
>Aric