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3 phase resonators



Hi All,

I have been experimenting recently with 3 phase resonators, and thought I
would share the information with this group. I've been selling a few solid
state coils on ebay, and thought I should do some more experiments with 3
phase while I have the resonators and drivers. I first used this controller
on 6 coils in 1992.

This is a photo of the typical set-up:

http://www.aros-dot-net/~gbyrd/tesla/3ps.jpg

This is a photo of the 6 phase generator:

http://www.aros-dot-net/~gbyrd/tesla/3pc.jpg

I have not produced any really outstanding results with my experiments, but
there have been a few surprises, which usually leads to more understanding
of Tesla coils. The first surprise was a change in the resonant frequency
of a system just by the phase change of the driving signals alone (no
physical change in the resonator). As an example, with a particular 3 phase
sytstem set for a rotary phase (3 coils and each 120 electrical degrees
apart), the frequency was 82 kHz. With just a change of phase drive to all
coils getting the same phase, the resonant frequency jumps to 102 kHz. No
physical change in the system. By the way, the resonant frequency of a
single coil (with an equivalent top load), is 91 kHz.

The fields of the coils must be changing the equivalent values of
inductance and capacitance (the transmission line people will say the
propagation velocity has changed, which amounts to the same thing). I will
let you make what you will out of this.

A simpler test is to use just 2 coils. With 2 of these particular coils
being driven with the same phase, the frequency is 95 kHz, and being driven
with 180 degrees out of phase signals the frequency is 78 kHz. Spacing
between the coils will change the frequency as expected, this just shows
there is a change in frequency just by a change in the driving voltages.

Here are some photos of driving 3 resonators with the same phase:

http://www.aros-dot-net/~gbyrd/tesla/21.jpg
http://www.aros-dot-net/~gbyrd/tesla/22.jpg
http://www.aros-dot-net/~gbyrd/tesla/23.jpg

If 2 coils are being used for phase experiments, it is easier to get the
resonant frequency as compared to 3 coils. With 3 coils the positioning of
each is more critical, as position of each in relation to the other will
affect it's individual frequency. All coils must be kept very close to the
same frequency, or one will produce sparks first, which will drain the
energy from the other coils and limit max energy. Even if all coils are
exactly the same frequency, one will normally spark first, and all
resonators tend to dissipate their energy in the one spark. When resonators
are being driven with the same phase, the sparks will always be away from
the group, never towards each other.

Sparks going towards the center of 3 coils can be accomplished by driving
each coil 120 electrical degrees from each other. I don't know how else one
could get sparks towards the center of 3 coils with CW type sources? Here
are some photos of 3 phase Tesla coils, producing rotary electric fields:

http://www.aros-dot-net/~gbyrd/tesla/10.jpg
http://www.aros-dot-net/~gbyrd/tesla/11.jpg
http://www.aros-dot-net/~gbyrd/tesla/12.jpg
http://www.aros-dot-net/~gbyrd/tesla/13.jpg
http://www.aros-dot-net/~gbyrd/tesla/14.jpg
http://www.aros-dot-net/~gbyrd/tesla/15.jpg

It is quite difficult to get the corona discharge from all 3 coils to meet
each other in the center (like a Y). More often the sparks will form
between each coil like a delta (3 seperate sparks between the coils, but
not touching each other). In these photos, the top of the resonator is 10.5
inches in diameter, which can be used to judge the length of the sparks.
These experiments prove that it is not impossible to control the phase at
which resonators are driven. Again, you can make what you want out of these
results.

When using 3 coils it is easier to get good results if they are driven from
symetrical phase sources. As an example, it is very difficult to get good
results with driving 2 coils with the same phase, and driving the 3rd coil
180 degrees out. The 3 individual coils will not have the same frequency,
so they will not work good as a system. Driving with the same phase, or
each 120 degrees different is symetrical and the coils will all have the
same frequency (if they are physically the same).

Happy coiling, Thor