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capcitor energy vs pwr factor
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From: Antonio Carlos M. de Queiroz [SMTP:acmq-at-compuland-dot-com.br]
Sent: Tuesday, February 10, 1998 12:53 AM
To: Tesla List
Subject: Re: capcitor energy vs pwr factor
bmack wrote:
> As far as power is concerned, there is no doubt that the cap disapates all
> it's energy when the gap fires, but I was quetioning how much of the
> AVAIlABLE power is sucks from the transformer.
> If current was really cosinsoidal and voltage was sine as previously
> suggested,
> it would only absorb about a third of the peak energy comparded to high
> power
> factor scenario. Do the integration for the hypothetical 15kv-at-30ma NST ,
> multiply by 120, you will see what I mean.
> Comments?
The actual waveforms for this system are rather more complicated if a
transformer with high series inductance is considered. The inductance
tries to resonate with the capacitor at the power line frequency, what
would produce increasingly higher peak voltages at each cycle, limited
only by the series resistance of the loop, that imposes a limit in the
current. But the spark gap discharges the capacitor one or more times
within each semicycle, blocking the resonance. This does not affect the
instantaneous current through the transformer series inductance, what
results in different initial charging currents in the capacitor after
each gap firing.
Tesla coils, while apparently simple, provide material for filling many
pages with the mathematics of circuit theory if you want the exact
expressions for what is happening.
The system that charges the primary capacitor is a good problem.
The primary-secondary coupled resonators, with a lumped model, is another,
more well known.
The secondary behavior with a distributed model (required?) is the most
obscure problem.
Antonio Carlos M. de Queiroz
mailto:acmq-at-compuland-dot-com.br
http://www.coe.ufrj.br/~acmq