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Re: Question about ballasting and VA
> Original Poster: "Ross Overstreet" <ross-o-at-mindspring-dot-com>
Hi Ross,
I do use inductive ballasting and I haven't (maybe others have) found that my
variac acts as an impedance matching component. I do notice that there is a
maximum amunt of current that the coil won't process further. However, turning
up my variac beyond this point does not reduce my spark length (like turning it
down will). On the other hand, my input current will climb and if I keep going,
I will pop the breakers even though the spark length doesn't increase. To me,
it is acting as a simple current limiter. It can appear magical when I start
increasing the current until the point of takeoff. When your turning it up,
there is a point where you start charging the caps to a potential to conduct
consistently at the gap rate. Thats when the sparks really fly and best arc
lengths are achieved. However, as I said, increasing current hasn't shown
itself in a decrease in spark length - just input current going somewhere other
than the sparks. At least, that's what I've seen thus far and it "appears" as
though the coil itself just cannot process further current into spark lengths
without making some kind of change to the coil itself.
Bart
> Hi Bart,
> I'm not even sure what I am trying to say, probably shouldn't be wasting
> bandwidth...
> I'm in over my head here. I haven't studied it enough or ran any
> simulations. I'm fortunate enough to hang out with some guys who run big
> coils and operating procedures made me rethink what the series variable
> inductor that everyone calls the "current limiting" variac is doing.
>
> The current limiting variac certainly doesn't behave as a big Tesla Coil
> "dimmer". There is a definite "sweet spot" on the variac that seems almost
> magical. Richie's variable inductor report is outstanding (as usual), but
> I'm not convinced that this is the same phenomena that is making the big
> coils run smoothly.
>
> I was hoping that some modeling had been done in this area or that someone
> had an intuitive explanation that my simple mind could grasp.
>
> Thanks,
> Ross-O