Modified Bowman Motor

Primary reference: 

http://www.freeenergynews.com/Directory/MagneticMotors/Bowman/index.html

In 1954 Lee Bowman invented a three-rotor permanent magnet motor using Alnico magnets, which was claimed to have worked as a perpetual motion, as shown below:—

The original Bowman motor

A modified version

After a quick look, I had not thought this motor interesting enough to investigate further, but a friend who was also interested in magnet motors eventually persuaded me to build a physical prototype of a modified version of it — see below. (This was a long time before I was able to do any computer modelling of devices like this).

(Most of) my modified Bowman motor

Unlike the original, this prototype used NdFeB35 magnets, and had only two rotors geared together, of equal size. The magnets on each rotor were arranged to attract those on the other rotor. The axle with the pinion on it originally passed through another piece of framework and carried a flywheel (these two items not shown).

As with the original Bowman motor, a separate fixed "actuator" magnet was arranged to repel the magnets on one rotor. The intention was that when a pair of rotor magnets crossed each other, the repelling actuator magnet would reduce the attractive forces between them at the end of the crossing, as they started to move apart again. (It would do that by reducing the flux density of the rotor magnet that it was repelling).

It is almost needless to say that this prototype did not work.

I had originally intended to add at least a second actuator magnet below the one shown, which would have doubled the energy output — had there been any — because each rotor magnet crosses with its partner on the other rotor twice per revolution. I never did that, since there was no detectable energy imbalance at all with the single actuator magnet.

Conclusion

Even though a version of the Bowman motor might possibly be made to work, at very low power output, with highly non-linear magnets (like Alnico, as used in the original version), I don't think it worthwhile to investigate this concept any further.