Re: Dual layer primaries

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Jason,

Tesla list wrote:

> Original poster: "Jason Johnson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <hvjjohnson13-at-hotmail-dot-com>
>
> Hello,
>
> Does anyone have any idea as to how to calculate inductance for a two level
> primary? I'm talking about a primary coil that is wound with two layers both
> going the same direction and seperated by an inch or so, inner turns
connected
> together, and tapped in two places, one on the bottom half, one on the top
> half. I know that I can't just calc. for one primary and then double it,
> because the halves are going to have some mutual inductance, resulting in a
> higher overall inductance than just doubling one of half the size, right?
Does
> anyone get what I'm talking abut here?

Sure, we get it. Some coilers have already done this and might be best to
give you an idea of the
inductance, however, trying to calc the inductance? I think you would be
better off simply measuring the
inductance with maybe a frequency measurement of the primary (secondary
removed). Maybe a quick mock-up
(simple stranded wire) will give you a good idea of the near inductance
once it's wound with the final
tubing (or whatever you plan to use).

Terry's TCTuner is something to consider. I've used it with great success
in conjunction with a frequency
meter. Also, contrary to someones statement a few emails ago that the tuner
is already calibrated is not
correct. The tuner should be calibrated if one uses the dial position as a
representation of the
frequency, however, I don't use it this way because a small change in the
dial can be a large change in
Fr. I simply find Fr with the dial, then, take the tuner away and measure
the tuenr itself with a
frequency meter (because I have one handy and it's far more precise). The
tuner is very easy to build and
comes in real handy for a great deal of misc. experiments like this.

 http://hot-streamer-dot-com/TeslaCoils/Misc/TCT/TCT.htm

Take care,
Bart