Tinselkoala's high voltage "Mendicno Homopolar".

[broli]

The title of this thread is a bit misleading, this seems to be an electrostatic motor. Another property of a homopolar motor is that rotation direction depends on current direction, correct me if I'm wrong but I don't think the direction of rotation changes when current is reversed?

[synchro1]

I wonder if a conductor disk placed close to the rotor might collect spill off power from the corona?

[synchro1]

The title of this thread is a bit misleading, this seems to be an electrostatic motor. Another property of a homopolar motor is that rotation direction depends on current direction, correct me if I'm wrong but I don't think the direction of rotation changes when current is reversed?

I chose that wording to imply:

                                    "High voltage electrostatic levitating motor and homopolar generator".

[TinselKoala]

The title of this thread is a bit misleading, this seems to be an electrostatic motor. Another property of a homopolar motor is that rotation direction depends on current direction, correct me if I'm wrong but I don't think the direction of rotation changes when current is reversed?

Broli, the videos don't show any testing of the homopolar components yet, and they aren't even installed on that last photo. But I have tested a couple of configurations and have gotten a few mV of homopolar output into a high-impedance voltmeter.

I cut out a disc from brass shimstock and mounted it right up against the rear ring magnet. I made a couple of small carbon-fiber brushes that have high conductivity and a very gentle touch, and using these as probes against the brass disc surface at the periphery and close to the center, I could detect the voltage, very small, but with the correct sign for the magnet and probe polarities and direction of motor rotation.

Unfortunately I also noted a couple of other things. First, the homopolar voltage is very small. The conductor path length is short and the magnetic field of those ceramic ring magnets is really weak. Second, the strong suspension magnets (these are epoxy-coated, very thin, N52 or even stronger, special purpose NdBFe magnets) create fairly strong eddy current braking on the brass disc when it is so close to the suspension.

I tried another larger brass disc glued to a plastic disk for rigidity and spaced further away from the suspension, but I couldn't test it for homopolar activity because I don't have another suitable magnet for it. Still, it produced enough aerodynamic braking and possibly also still some eddy braking that it slowed the top speed of the motor by half, down to a bit over 2700 RPM. I have some stronger ring magnets coming soon, I hope, so I'll be setting up for more homopolar trials when they arrive.

[TinselKoala]

The title of this thread is a bit misleading, this seems to be an electrostatic motor. Another property of a homopolar motor is that rotation direction depends on current direction, correct me if I'm wrong but I don't think the direction of rotation changes when current is reversed?

Current reversal.... well, most electrostatic motors, including this one, cam be biased in one direction or the other by the geometry of construction. If I adjust the electrodes so that they are exactly on the disk diameter, then this motor will spin equally well in either direction but needs a little push to start. If I move the negative brush to where it is about 1/3 the circumference away from the ball, then the motor will usually self-start, turning from brush to ball in the shortest direction, and it prefers to spin that way. If I reverse the polarity of the electrodes, putting the cathode to the ball and anode to the brush, then the motor will still spin but not nearly as well. Directionality response same as above.