On 12/4/21 6:53 PM, Joshua Thomas wrote:
> Hello all,
>
> I'm starting to think ahead about connecting measurement equipment to my
> SGTC. I have experience with measurement of sub-kilovolt equipment, but not
> with the higher voltages a tesla coil produces. I would be interested in
> hearing about the measurement equipment and connections that other coilers
> have used.
>
>
> Secondary circuit voltage and current measurement: The topload has
> something like 300kV or more, and there's not really anywhere to tap into
> that doesn't effect the circuit directly. My only guess here is remote
> electrostatic sensing. I have absolutely no idea how to implement or
> calibrate this. Definately interested in experiences from coilers.
>
> Thanks in advance,
> Joshua
>
>
Here, probably the best way is to measure the voltage indirectly, using
the capacitance from top load to an electrode some distance away (out of
spark range!) - a flat plate with the flat side facing the secondary.
You'll want some protection in case a spark does hit the plate, so your
scope doesn't become the "path to ground.
You'd calibrate by hooking a signal generator with known output to the
coil's topload at a known voltage, with the secondary connected (with
the primary power off, of course).
Do it at a series of frequencies, and you can figure out what voltage on
the sensing plate is equivalent to what voltage on the topload.
If all you're interested in is the waveform, then you don't need to
calibrate.