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Re: 2 questions on resonance
In a message dated 99-04-03 21:09:00 EST, you write:
<< Number One:
> What is resonant charging?
Chris,
Resonant charging occurs when the inductance of the TC power
supply equals the capacitance of the TC tank cap. Under this
condition, with L and C equal, only the resistances in the system
limit the current input. In an NST system, the cap should be
matched to the NST to give resonant charging. The cap capacitance
will then neutralize the leakage inducance of the NST. For instance for
a 15kV, 30ma NST, the resonant sized cap is 11nF, but up to
15nF will work well. It is important to realize that using resonant
charging, an NST can draw double or more its rated current input.
This is good from the standpoint that you can get more spark output
than otherwise, but bad from the standpoint that it stresses the
transformer a little more than normal. There's a formula for selecting
the resonant cap size, which I don't have handy,
but I'm sure someone else will post it. Using resonant charging,
in non-shunted xfrmer system, the ballast inductance can be
adjusted to give resonant charging.
> Number Two:
> What is the cause of a resonant rise in voltage?
This is what occurs in a child's swing when you push at the
correct times to build up the swinging height. Each push, pushes
the swing higher and higher. Likewise in the TC circuit, each AC
cycle pushes the voltage higher and higher. This is why it is
important to have the spark gaps, and safety gaps in place when
testing resonant charging TC systems, otherwise, the voltage will
build higher and higher (limited by system Q) until the cap or
transformer is destroyed by overvolting.
John Freau
> Chris, via the inter-thingy
>>