On Sun, Feb 17, 2019 at 8:04 PM derstrom8--- via Tesla <tesla@xxxxxxxxxx>
wrote:
> Okay, that makes perfect sense. I am very familiar with the parasitics
> associated with Tesla coils and their circuits, so that is understood. I'm
> definitely still learning here. Thanks to you and Antonio for your very
> informative responses!
>
> My initial question for Doug about reducing capacitance and increasing
> primary turns was based on personal experience, mainly (and I think someone
> told me once that more turns is better, within reason). My DR originally
> had higher capacitance and fewer primary turns, and the output was not
> terribly great even when tuned. I eventually reduced the amount of
> capacitance and added half again as many turns and after tuning the
> resulting arcs were noticeably more impressive. I suppose that could have
> been affected by a variety of factors though.
>
As Antonio pointed out, the power transformer is usually the weakness of a
single turn primary system, as it takes higher voltage to push power
through a smaller primary. The same goes for blowing air through a hole.
The smaller the hole, the greater the pressure you need to maintain the
same air flow.
The weakness on the primary side is only part of the battle. The secondary
system of a Tesla coil behaves like a Helmholtz resonator. The primary is
the whistle hole. It you are going to build a working resonator with a
single turn primary, the cavity of the resonator must be designed to
account for the ability of the power transformer and primary.
Most of the solid state Tesla coils I have seen are setup more like high
voltage transformers than high voltage oscillators. High voltage
transformer coils are still interesting, but they are different in
principle from high voltage oscillators. The difference is in the way the
electrons are stressed.
In a single turn primary type coil, the electrons are stressed to the max.
The electrons swing from a high current state (made possible by the single
turn primary) to a high potential state. With high voltage transformer
coils, the electrons do not have as great of a spread between high current
and high potential. There is still enough high potential to create sparks,
but they don't "dance" as interestingly, or create as strong of an electric
field. For example, if you are looking for corona effects, you will want to
build the high voltage resonator around a single turn primary and design
your power supply and secondary system accordingly. If you just want to see
sparks, you can build a Jacob's ladder with a transformer.
Of course, the spark gap has to discharge and quench with as short a duty
cycle as possible to make the primary work most effectively.
Dave
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