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Re: SGTC
Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>
Tesla list wrote:
Original poster: Frank <fxrays@xxxxxxxxxx>
An interesting question for the group:
Which circuit makes a better SGTC and why?
The main difference is what the power transformer sees at its output.
1) The cap in parallel with the HV transformer and the spark gap in
series with the TC primary
The transformer sees high-frequency oscillations when the gap fires.
This may damage its insulation.
2) The spark gap in parallel with the HV transformer and the cap in
series with the TC primary
The transformer sees almost a short-circuit while the primary circuit
is oscillating. Each current reversal
produces a fast transient as the gap refires, but the stress on the
transformer is much smaller. If there
is no arc quickly draining the energy at the secondary, after the
primary gap opens the transformer sees
a long burst of high-frequency oscillations, but with smaller
amplitude than in the first case. Transformers
with short-circuit current limited by dispersion inductance, as
typical NSTs, can be left short-circuited
for long time. The short-circuit current of the transformer is
insignificant compared to the RF gap current.
3) The SG in parallel with the HV transformer and caps in series
with EACH side of the TC primary
The transformer sees the same waveforms of case 2. Protection against
low-frequency shocks is better.
It may appear that the capacitors must be two times larger than if
they were just one. But with an MMC
construction, the MMC can be just split in two.
In any case, it is advisable to use a filter between the power
transformer and the primary circuit.
Antonio Carlos M. de Queiroz