Re: the cure for racing sparks

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "boris petkovic by way of Terry Fritz <twftesla-at-qwest-dot-net>" <petkovic7-at-yahoo-dot-com>



> >I fly a twin engine Piper Aztec and the same exact
> effect occurs.  If you
> >get one prop running just 10-25 rpms above the
> other there is a noticeable
> >beating effect which is corrected with the prop
> governor controls (prop
> >pitch).  The "beats" will drive the pilot nuts in a
> few minutes if not
> >corrected.
> >
> >The same principle applies to Tesla circuits. 
> Exceed critical coupling and
> >you have a HV peak at some other point than the top
> of the coil and "racing
> >sparks" can occur.
> >
> >Coupling adjust, as you mentioned, is the cure.
---
I assume under term "critical" coupling you consider
dangerously high coupling factor which causes TC
system starting racing sparks to appear.(Speaking of
which  ,term  critical for coupling means something
else in theory of resonance of coupled systems)   
However,I must disagree that overcoupling itself in a
properly tuned TC system (resonant frequncies of
primary and secondary close) can produce HV peak at
some other point of the coil than its top unless heavy
detuning is present.The analogy you mentioned here
isn't too good becouse those were "beats" caused by 2
forced CW frequencies.  
Increased coupling coeficient(up to 0.25)  does not
even produce gross local voltage gradient increase
along typical resonator lenght geometry for a given
secondary energy as thought once.Up to few % as
simulations show.
On other hand,in reality,It does produce higher
voltages and other things what Paul N. already
mentioned.
---

> >
> >Many beginners have set up coils without enough
> primary inductance 
> >available
> >to tune properly and this also produces the same
> effect.
> >
---
Yes,significant tuning error may cause various
wildernesses along secondary structure including  HV
peaks and gradients elsewhere.
There is possibility that "begginer" who uses only a
turn or so in primary winding and big cap gets a mess
throught discharging process in Fp that could cause
further problems.TBD.

Cheers,
Boris