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Re: SRSG firing problems


The value of capacitance is causing a phase shift in the NST as you advance
the variac.  This is common in NST setups, and sometimes a full wave bridge
off the NST is required to eliminate the undesireable 60 Hz resonance effect
which shift the phase of the HV as it tries to charge the cap.  This is
usually more common in systems running with synchro RSG's where the phase
shift is so great it causes the stationary electrodes to hit peak potential
when the RSG electrodes are not in proper alignment for firing.  If you
rotate the rotor then the system runs fine at high variac settings but
doesn't run at all on lower settings.

A dead giveaway that this is happening is if the unit runs nice at lower
variac settings and then acts weird at higher levels --- like not firing at
all!

To test for this, just substitute a stationary gap and see what happens.  If
you still have problems then it is something else like the cap breaking down
internally or something.

Best 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: Tuesday, January 04, 2000 11:58 PM
Subject: Re: SRSG firing problems


>Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>
>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
>
>
>