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RE: Dramatic Performance Drop After 5 Seconds?
>>but thinking about it now... if you had an air flow across the gaps you
>>may not have blown your caps ;)
>>
>>Scot D
>I don't think so Scot. One parameter that's influencing positively the
>induced primary voltage is dV/dT. When the spark is blown out by an
airflow
>the change in Voltage (dV) divided by the change in Time (dT) is increasing
>thereby increasing the induced Voltage in the primary coil and thereby
>possibly over-stressing the capacitor. So, the opposite of your
proposition
>is true. That's the reason that rotery gap's are working better than
>stationary gap's.
>
>Ruud de Graaf
>Greetings from Holland
I don't see how airflow can possibly affect the dV/dT of the tank circuit.
At the time of quench, the current through the gap is zero and the voltage
on the on the tank cap is at it's diminished maximum value (few hundred
volts) and minimum dV/dT. The maximum dV/dT occurs when the capacitor
voltage is passing through zero (and gap current is maximum and quench is
impossible), and is dependant strictly upon the peak capacitor voltage and
the values of C and L, and any resistance in the tank circuit
I agree that airflow across static gaps may reduce stress on tank caps, but
the reason is that airflow improves quenching. The sooner the gap quenches,
the less time the tank circuit spends oscillating per bang-period.
Gary Lau
Waltham, MA USA