# Re: How to rise the secondary? (vmax x power) (fwd)

---------- Forwarded message ----------
Date: Sat, 18 Jul 1998 19:02:09 -0700
From: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: How to rise the secondary?  (vmax x power)

John Couture wrote:

>   In your teslasim program example below what input watts are you using to
> obtain the 313KV secondary voltage. Wouldn't changing this input wattage
> change the secondary voltage? With the JHCTES program the secondary voltage
> is affected by the amount of input wattage.

The simulation was for a single shot without breakout in the secondary.
The primary capacitor was charged to 10 kV and connected in parallel with
the primary coil (by the spark gap, assumed as an ideal switch in that
example).
More input wattage (or for a single shot, more initial energy) can affect
the output voltage if the input voltage (Vin) is increased, what
happens when a variac feeding the input power transformer is turned up,
or the primary capacitance (C1) is increased and the system retuned.
The maximum output voltage will then follow the rule:
Vomax=loss_factor*Vinmax*sqrt(C1/C2)
An increase in the break rate can only result in more output voltage if
there is still some energy left in the system from one break to the next.
This is what happens in a CW coil, but is known to be very difficult to
obtain in a capacitor-discharge coil (too high break rate or too high Q).
If you map spark length to secondary voltage, an apparent increase in the
secondary voltage may appear if the break rate is increased, but this is
because new breaks use the same streamer/spark channels of previous ones,
resulting in longer sparks/streamers for the same (or smaller) maximum
secondary voltage. If you control the input wattage by the break rate
only, the spark length can be affected, but not the maximum secondary
voltage.
There is, however, a case where actual increase in output voltage may
appear in proportion to the break rate only. If the primary circuit is
tuned to "best spark length" at high power, if the break rate is reduced
the system may fall out of tune, because the additional secondary capacitance
caused by attached streamers will not be present. The detuning will
decrease the maximum output voltage for low break rates.

Antonio Carlos M. de Queiroz