I have been working on this idea for several months and I have had some success, but have also run into some problems. It sat in my closet for the last few months and I recently dug it back out to see if I could improve on it. The small prototype I built uses a number of parts from several erector sets and 2 of the 6 volt motors that come with them. One motor acts as the input and the second acts as a generator used to recharge the AA batteries in the battery pack. Without the belt hooked to the generator motor it will run for an average of 20-25 minutes, with the generator hooked to the system, closing the loop, it has run as long as 56 minutes but each time there are screws that start to come loose and invariably the parts begin to loosen up too much and the rotating parts start to bind and the system stops. It has never quit due to loss in voltage from the batteries. The motivating aspect is after this happens when I check the voltage left in the batteries there is very little loss in the voltage, although it varies quit a bit from each run. I have only been able to get it to run over 40 minutes one time, as the other times it begins to come apart due to the vibrations and screws coming loose.

Here is a basic idea of the mechanics...

(http://img232.imageshack.us/img232/9454/crankarmwa9.gif)

I got the idea came from...www.evert.de/eft299e.htm

The blue arm is hooked to the input shaft and the red is hooked to the output shaft and then the generator by a belt and pulley. If you watch the red arm it increases and decreases speed in one revolution while the blue or input shaft maintains a consistent speed. The red, output, shaft transfers the force through a one-way bearing between the shaft and pulley. When you pedal a bike at 10 mph and the bike is traveling at 11 mph, you are "free-wheeling" and no force is going to the wheel. Once the bike slows to just under 10 mph you feel the pressure on the pedals to maintain 10 mph. When the red or output is speeding up the resulting inertial force is used up turning the flywheel/pulley and balances itself out.

Here is a picture...
(http://img135.imageshack.us/img135/6460/200804190002eq1.th.jpg)(http://img230.imageshack.us/img230/9489/200804190008fz8.th.jpg)

I am iterested in ideas or suggestions. The only bearing is the one-way bearing used between the output shaft and pulley used to turn the generator motor, which by the way has begin to melt the outer plastic casing. I have tried to find other bearings, mostly from RC cars, that would lower the friction, but have not found anything I can make work. Many parts in the erector sets are very imprecise and nothing spins true, Therefore all the spinning parts have to be assembled loosely for it not to bind and stop. I have hooked a volt meter to the output connection at the battery pack and it fluctuates between .3 and .5 volts.

It seems to me that there are 3 main variables, although I am sure there are more including the path traveled by the weight at the end of the green arm, that are required to make this work and it all hinges on the force required to spin the generator. The weight on the green arm and the speed it is spinning causes an inertial force in the same direction on each revolution. If the force required to spin the generator can be exactly matched by the inertial force developed then it would balance itself out. I wonder if there is any software out there designed to calculate that type of thing? Once the formula is achieved the output of the generator could be increased by increasing the weight on the green arm or the speed it spins or both.

Any ideas, suggestions?