Each fan I have tried as from the manufacturer is a bifilar wind going through all 4 coils I split the two ends per your video however nothing happens.
Now I have 3 non-fans.
In all of your fan videos you do not show the type of power supply being used, I assume a general variable dc supply does the trick, I am not sure if there needs to be something on the charge side, the videos elludes to not needing anything on the charge side in order to set the circuit. Once set then put somthing on the charge side.
I took one of them and rewound the bifilar so that 2 poles are now separate from each other this too had no effect.
Is there something missing from the videos (that are posted under Imhotep that show how to build the circuitry)? Do I need to pull bifilar windings off of the 12v fans and rewind them per your bifilar winding video of cw/ccw/cw/ccw such that the bifilar winding connects through all 4 poles then having the 2 separate pairs to put through the schematic that you generously supplied?
We are using a standard power supply as the voltage in, with a cap for the charge circuit.
There are several possible reasons for the fan not to work
1) have you got the coils connected in the right way? there are several possible ways to connect the coils but only one works. I found trial and error the best way to identify this.
2) Is there enough voltage to run the device? computer fans from different manufacturers have different resistances, because of this some need as high as 13v to get them to run on this circuit.
3) Has the transistor failed? Even some brand new transistors will not work, but it is possible that trying to get it to work can burn out the transistor. What transistor are you using?
4) Is the potentiometer ok? I have found that often the pot will burn out, also as the circuit sometimes only requires a small resistance the pot may have too high a resistance. I use wire wound pots.
5) is the diodes ok and are they the right way around? Self evident but always worth checking.
6) Are the coils ok and is there an internal short? Its always worth doing a continuity test.
The first three are the most likely if everything else looks ok.
I used 12v lead acid batteries or sometimes a 12v transformer (battery charger) as a power supply. It all depends upon the fan, some will run as low as 5 volts.
It is possible to run the fan without anything on the charge side provided you have a neon in place but even so, this can pop your transistor or the neon. As a rule, I would say, always have the device connected to a charging battery, of course with the charging battery in place the neon wont light up.
The standard method of winding works best in my opinion. dont bother to separate out the different poles.
Hope this helps