Hey Stefan you forgot the coils are bifilar to cancel out the flux.
This is visible in the pictures too... it's two wires.
M.
Marco,
no it does not make any sense !
Why should it cancel out the flux of the control coil and be bifilar?
I see in your posted picture that it could also be just the 2 wires of the
control coil going to the stand-box, where maybe a big capacitor just sits there
to do a phase shift.
The 4 coils of the OpenTPU are probably connected this way,
that 2 opposing control coils are in series with a big cap in parallel so these 4 coils plus 2 caps form
2 LC tanks which are 90 degrees out of phase (in quadrature).
So if these 2 LC tanks oscillate they generate a rotational magnet field.
Then the white single turn collector coil wire,
which is taped under the red control coils
to be hidden ( can only be seen in some places, otherwise
taped by black tape)
generates the output DC voltage.
If you remember Jack said,
SM just used these stands from plastic loudspeaker holders,
so the spool frame where he put it all on, is just plastic all the way...
No more mystery here.
Also the 2 magnets are probably just put there to switch on
2 reed relays, that keep the 2 LC tanks disconnected from each other.
The white loose wire in the center of the OpenTPU is just there
to connect the loudspeaker type output connectors at the top to
the other output connectors at the right side.
Remember SM connects the voltmeter to the upper
loudspeaker type output connectors and the 2 bulbs to the side output connectors.
So the white wires in the center hnaging loose there are just there to make a parallel
output connection from loudspeaker type output connectors to side output connector,
nothing more...
It would be easy for e.g. Roberto to do these tests,
as he has all the required hardware.
The only thing he would have to change is use
a shiftregister pulse control setup and pulse his
control coils in a sequential order to have a rotational
magnet field for his control coils and then see the DC voltage with hash on
the output coil.
This would be the first test to see, how the DC voltage is generated.
Then we just have to find out, how we have to connect the 2 LC tanks
to the output coils and to each other to violate Lenz law and keep
the oscillation running.
It is a pretty simple circuit I guess and easy to setup,
once you know how the connections are to be made.
Regards, Stefan.