After building and examining the Hybrid Linear Generator we started working on the problem of converting the reciprocating motion of the bobbing point absorber into one-way rotary motion to drive a regular spinning generator to make electricity.
Steam diesel engines are the best known instances of this type of mechanical conversion as well there are devices for converting rotary motion to reciprocating motion.
However all of these devices require a fixed length piston and conecting rod and will not work when the distance of one of these rods varies as is the case with directly using unpredictable water waves as the prime mover.
A look at wave machine patents shows a concentration of patents that teach the use of a reversed rack and pinion system where the driving force is on the rack to turn the pinion. However in practice the rack and pinion only works well when the pinion drives the rack.
Other patents teach the use of chains to convert reciprocating motion to rotatial motion but only where the rotation motion is bi-directional, which results in making the generator turn in two directions which we have seen in the case of the more directly and simply driven linear generator has unsatifying results.
Still other wave patents teach the use of using various combinations of gears to achieve one-way rotational motion from reciprocating motion, however our study did not convince us that the gearing method would work satisfactorially with the large variation in wave height one would encounter in real ocean wave condidtions, for example from waves of 4 inches to 12 feet (0.1 to 3.6m).
We finally developed a method solving the problem of converting largely varying length reciprocating motion
into one way rotary motion yielding power on both the up & down stroke.
Neptune 1 - a regular spinning generator
Here is a video of a device using this method driving a 500 lb flywheel from 8 inch high waves with a period of 2.3 seconds made by a hand powered wave maker in a Vancouver, Canada wave tank.
After we had the flywheel spinning we replaced it with a 3 phase AC generator we made that can produce electricity over an equally large range of variable rotation speeds.
The video below shows the model producing electricity with an open circuit voltage of 240 Volts AC (single phase) at 47 RPM from 8 Inch (20 cm) Waves
Full 3 Phase Voltage Produced = 415 VAC
Neptune 1 - electicity from water waves