The amount of power that a homopolar generator produces varies in direct proportion to each of three parameters. a) radius of the copper disk, b) how fast the disk is spinning and c) the strength of the magnet's magnetic field. This has always been the crux of the problem ie. if you spin the copper disk twice as fast you get twice as much power but you also end up using twice as much power to make it spin faster.

If the circumference of the 'disc that spins' is itself surrounded by solenoids (tubes containing elliptical copper windings) such that each solenoid contains a magnet that can move up and down within the solenoid tube to generate electricity, then the following situation arises.

As the disc rotates, the magnets inside each of the peripheral solenoids would move up and down (like pistons).

In this way, 10 or 20 solenoids on the circumference of a single disc can generate more electricity than would be possible from a single copper disc.

I hypothesise that numerous peripheral solenoids can generate more electricity than is consumed by an electric motor capable of rotating a central supporting disc at optimal RPM.

In this case, optimal RPM has a lower limit defined by the requirement to generate meaningful electricity, and an upper limit defined by gravity.

Which is to say, the magnets inside the solenoids cannot be allowed to become pinned to the top of their solenoid by centrifugal force (should the central disc rotate too rapidly).

There is a formula for calculating the electrical output of each solenoid (based on the number of windings (copper turns) and the length of each solenoid etc).

In crude terms, multiply the output per solenoid by the number of solenoids on the circumference and you get total electrical output in watts.

The force required to rotate a central disc at the required speed can be calculated if you know the weight of the disc array (disc + solenoids + magnets in kg) and the acceleration of the circumference of the disc in m/s/s.

Once the force in Newtons is known (F = m*a), the power in watts needed to rotate the disc at the required RPM can be calculated using another formula.

Once you know the power in watts needed to rotate the disc, you can then compare power consumption with power output.

In all such mechanical systems, the strength of the magnet is a factor, but so too is the distance between the magnet and the copper.

The speed at which the magnet moves over the copper surface is important. The faster it moves, the more power is generated. But even if it were to move very quickly, it would not generate electricity unless there are 'changes' in direction.

Most neodymium magnets have enormous power (1.3 Teslas is not uncommon), but if the distance between the magnet and the copper exceeds a fraction of a millimetre, field strength falls exponentially.

On the flip side of the coin, even if you were to engineer a system in which a magnet close to the copper could change direction very quickly, the high field strength would itself require enormous torque (rotational force) to rotate the disc.

For these reasons, I have suggested having a central non-copper disc around the circumference of which solenoid magnet arrays provide rapid rates of change.

Magnets, moving like pistons in the cylinders of a combustion engine, would generate electricity whilst at the same time the torque requirements of the central disc would not be a significant limiting factor.

It might work particularly well in zero gravity if springs of differing specifications were attached to each end of the solenoids. One could simply ensure the spring at the 'outer circumference end' of the solenoid was much stronger than the spring closer to the hub of the supporting disc. This would prevent magnets getting stuck at one end of the solenoid due to centripetal force.

Dense neodymium magnets would move up and down inside the solenoids, bouncing off the springs at each end, providing rapid rates of change (and thus high electrical output).

Angular velocity in radians per second at the circumference of the disc would not be restricted by a speed limit preventing magnets travelling at more than 10 m/s/s (the rate of acceleration of gravity).

Large solenoid wheels in space might therefore provide electrical generating capacity that would otherwise require impractical arrays of solar panels. In addition, power would be available for propulsion beyond the influence of sunlight. This would allow us to send automated probes well beyond the confines of the solar system.

The size of a solenoid piston array in space could be enormous. High electrical output from such arrays could be used in manned spacecraft for propulsion systems requiring greater output than that available from solar panels.

Interesting thread. Thanks for putting it in the public domain. I particularly like the idea of using electromagnets in the way you suggested.