Re: Advice on Increased Power

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Emmett,

The voltages out of the NST farm will be the same as one NST so sparkgap
settings should remain the same (it doesn't hurt to recheck the safety gap
setting).  With double the current, you will need to double Cp to keep the
same charging levels.  Clearances required between primary and secondary
should remain the same.  If you don't change the top load you will need to
half the primary inductance (with double Cp).  Probably need to compare
predicted streamer length for the double power level with the winding height
of your secondary to make sure the coil is not overpowered (strikes to
primary or its strike rail, overvoltage between turns resulting in racing
sparks - reduce coupling if the later is a problem).  With twice the Cp, you
have the potential for twice the top load voltage (Cp/Ctop * Vcp) so you
could go to a larger toroid for optimum performance.  Use JAVATC to
experiment with toploads and compute the resulting voltages and Ip peak
currents.  Use "inca" (Antonio's tool) to compute toroid breakout voltages.
If number of primary turns is too small with the larger Cp, you can add
topload capacitance or secondary inductance (more turns or larger diameter
secondary).  Also it will be more important to bring the system up slowly
with a variac while looking for problems.  Tune at lower power levels and
retune at higher power levels.  Do short runs, power off, and see if any
component is getting warm.  Make sure properly discharged before touching,
but you already know this.

You're having great sucess and good luck with your next step,

Gerry R
Ft Collins, CO

 > Original poster: "EMMETT SECREST" <secrest2032-at-msn-dot-com>
 >
 > I guess that like most new coilers, now that I have my first one working I
 > want to increase the primary power level. I have purchased another 12/60,
 > ordered the caps and will soon be adding the second NST.  What I would
like
 > to know from the list is what parameters will need possible alteration to
 > accomodate the increase from 720VA to 1440VA.  Specifically stuff like,
 > coupling factor, primary to secondary relation(vertical as well as
 > horizontal spacing), top load size, safety gap setting, spark gap setting.
 > I hope you will forgive me for hitting you with so many questions. I just
 > don't want to un-necessarily fry something now that I have it working so
 > good.  I know I have to phase the NST'S, just to get that off the
 > agenda.  I am not looking for an easy way out, I am willing to work out
the
 > small details. I just don't want to make a major mistake. Thanks in
advance
 > for your help and advice.
 >
 > Emmett
 >
 > _
 >
 >