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Re: SRSG firing problems

At 09:08 PM 01/03/2000 -0800, you wrote:
>Hello, all
>
>Now I've run into more problems.  I hooked up my coil again (finally!) and 
>ran it with my new SRSG. It fires for 1 or 2 presentations, then stops and 
>won't start again. The transformer (15/60) is still buzzing, and I can hear 
>the wires I run it through to the coil buzzing too like they do normally, 
>but the gap won't fire.
>
>I tried out the setup without my rotary, with my RQ gap on about 9 sections. 
>  0.003" spacing.  I got good strong 9" of output, which unfortunately is a 
>new record.  Too bad.  I would much rather have the new record be 30 or 40", 
>breaking my previous of 8".  :(
>
>I am now running it with 10nF of capacitance.  I really think I should be 
>getting more output if I can get the darn rotary to fire.
>
>Does anybody know what I could do to make it work?  I don't appear to be 
>getting any breakdown in the caps (at least the one in the tupperware bucket 
>I can see), and have run it again and again, turning it on, (Bang! rotary 
>fires 1 or 2 presentations, then stops) and off.  Then on again, same thing, 
>and off.  the transformer is buzzing all the while.  Shoot!  the electrodes 
>are WELL withing firing distance.
>
>What should I do?  If I can get the rotary to work, then I can start trying 
>to add more primary turns and tune it further.  But until then, I am feeling 
>a bit at a dead end.
>
>Thank you!
>
>regards,
>Nathan
>______________________________________________________


Hi Nathan,

	I have run some numbers on your coil.  I will list them all here so that
others working on this can refer to them and so you can check if I have
done something wrong.

Charging Circuit

	One or two 15kV/30mA neon transformers running from 120 VAC.
	Safety gaps.
	Synchronous rotary gap that is proven to be synchronous.  A static RQ
style gap is available.


Primary Cap

	One or two 0.005uF polyethylene sheet oil caps.


Primary Coil

	15 1/4 turns of 1/4 inch copper tubing.
	10.5 inch inner diameter.
	23.5 inch outer diameter.
	36 degree conical.
	1/2 inch pitch (0.190 inch horizaontal).
	5 inches tall.
	I get a maximum inductance of 124.9 uH.


Secondary Coil

	7 inch diameter T-600 PVC.
	24 1/2 inches of #20 wire (0.032 inch dia.)
	765 turns.
	I get 23.0 mH inductance.
	

Top Terminal
	23 inch outer diameter dryer duct toroid.
	7 inch cross section diameter.

	Also available,
	14 inch outer diameter toroid.
	3 inch cross section diameter.

Primary to secondary coupling is "guessed" to be 0.172 (just right).

I assumed the base of the primary was 5 inches off the floor.
The first winding of the secondary was raised 1 inch up from the base of
the primary.
The center of the large toroid was 10 inches above the top winding of the
secondary.

E-Tesla5 predicts a secondary fundamental frequency of  188.5 kHz. 

Your primary at 125uH and the two caps together at 10nF will have a lowest
frequency of 142kHz.  So you should be able to easily tune the coil.
WinTesla says that will be at 12.4 turns.

Apparently everything says that your coil should be working fine. 

I would stick with the static gap for now until this streamer problem is
figured out.

I worry about what the "demand controller" you mention may be doing.  I am
not sure what this thing does but perhaps it is causing your spark gaps to
run for a few shots then shut down.  If there is a bypass switch or a way
to wire around this thing, that may be best...  I would think such a gizmo
would not like seeing a Tesla coil as a load and may do bazaar things...

Something appears to be wrong with the neons or primary caps.  I am
beginning to strongly suspect the caps...

Sooner are later your coil will work great!  It is just proving to be a bit
more interesting than most ;-))

Cheers,

	Terry