Re: MMC Design and Wiring

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>

Tesla list wrote:
> Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>
>
> My question was about the inductance of the caps themselves.  The CDE
> 942C20P15K have an ESL = 32 nH.  A string of (12) is still negligible to
> my primary inductance(so this question is more theoretical than
> practical)  My question is if I reverse every other cap would I reduce
> the total string cap inductance.  The question goes to the direction
> that the foil is rolled inside the cap and how the cap is
> terminated(internally).  If the caps are all built identically(as one
> would expect production product would) and I reverse every other one
> won't the current flow in the opposite direction around the axis of
> every other capacitor and reduce the inductance of a string?

The connections in these capacitors are at the sides of the roll,
not at the ends of the rolled strips, so the inductance is quite
small, comparable to the inductance of a wire having the length
of the capacitor. 32 nH corresponds to a straight wire with
3 to 4 cm of length. And this value probably counts the capacitor
leads too. If you just assemble the capacitors side by side, with
connections in a zigzag pattern, the currents flowing in opposite
directions in adjacent capacitors will reduce the inductance.
To maximize the inductance, assemble them in a coil pattern.
But it is not important to minimize the inductance of the capacitor
in a regular Tesla coil, unless your primary inductance is very
small (single turn). The extra inductance just adds to the inductance
of the primary coil and the wiring.

Antonio Carlos M. de Queiroz