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Re: Arcing and current

>>>> I would think that this would screw up the tuning.  When your secondary 
>>>> is not arcing, you would have one inductance, and when it arcs, it would 
>>>> be like removing a section of the coil and replacing it with a resistance. 
>>>> I would think that this would change the inductance (and resistance) and 
>>>> consequently the tuning would change depending on whether it's arcing 
>>>> or not. 

That sounds like it makes sense.  I "fixed" the secondary that we are talking
about with a bunch of epoxy on the outside and between the windings.  Once 
it cured, I was ready.  This saturday I fired the thing up and noticed several
things (I don't remember the exact order though): What looked like a cobweb
type of discharge between the tap clamp on the primary and the outside of the
secondary.  Then I heard this strange hollow sparking sound.  Later, I saw
a bunch of sparks all over the secondary.  After a bit of investigation, I 
discovered that the hollow sparking sound was an arc inside the secondary.
The arc was about 2" long and left a small carbon track on the cardboard.
Therefore, I think that I will replace the entire secondary with a plastic
tube.  I have heard that using concrete forms is bad because they are 
somewhat conductive.  Based on saturday's experience, I would have to 
agree.  I think I will try using a PVC or HDPE tube next time.

>>>> Hooked up normally, a variac is simply a transformer that allows you to 
>>>> vary the turns ratio, which will vary the voltage directly, not limit your 
>>>> current.

Does this mean that the current that can be drawn from a variac is limited
only by the "meltdown current"?

Chip