Re: Coupling Experiments

Hi Mark and everyone,

> I think there is a significant tradeoff between capacitor size,
> spark gap design and transformer "stiffness".  If one could send a
> high charging current to the capacitor, it appears that a high C,
> low L primary would work well.  Obviously, a number of individuals
> have been very successful with this combination.  However, high
> current capability means that a power arc may be difficult to
> quench in the spark gap.

I am just about at the point where I will do exactly that. I plan to
switch to uWave transformers. The basic plan is to use a couple back-
to-back (more paralleled if needed) and rectify them and use a 
charging choke to boost the output. I suppose fundamentally there's 
not much difference between that and using high inductance 
transformers. But I think it would be more controllable. More 
transformers in series is another option, but some form of current 
limiting would be a must I think. The other point is that it is much,
much easier to build caps that will survive at lower voltages and 
still perform well. The coil at work has its gap set to only 5kV,
but allows the use of easily built poly caps although the ones we
build are run in air and eventually die due to internal corona des-
troying the plastic. However, we have always been able to put a new
one straight into service and be confident it's not going to blow.
The coil itself is not a model of efficiency but that could 
definitely be improved.
    On the subject of capacitors, I brought my suspect CP cap in from
home and measured it on the bridge this morning. It measured 26.1nF
compared with 25.1 when I first got it. I don't know what's going on, 
but something seems to have changed. I'll take it home and try it 
again this weekend.