I stumbled across something that might just be what we are looking for. We achieved 10cc/sec output with a 9" 9 tube setup using an alternator as shown in the pic labeled astuart's circuit. As you can see we connected the output to the input of the PWM. This worked to produce about 6cc/sec. Since we wanted to increase this to at least 10cc we decided to add some electrolyte to the water (we had been using tap water only till then). What we chose, or actually had on hand, was baking soda. I added about 4 tsp to the water and found that the current draw from the battery through the feebback loop directly to the cell was so great that it didn't leave enough to energize the rotor windings. We came up with the idea of putting a switch int the line to the cell so that we could energize the alternator then flip the switch to the cell. This didn't work at first because the draw from the cells would drop the voltage to the rotor and we would no longer have output from the alternator. We decided then to add just 1 tsp to the cell and this worked. We measured the output at 60cc in just over 6 secs. However the wires leading to the cell were overheating, (14 gauge). So we shut it down and replaced them with 10 gauge wire. Here is where we found another problem with the feedback loop. If you didn't engage the cell into the circuit within a couple of secs the alternator would have a runaway and smoke the PWM. In the second photo you can see I modified the circuit by adding a couple of resistors, a zener diode to help regulate the voltage and another diode to block current from the battery directly to the cell. I haven't tested this new circuit yet but thought I would show it to you guys and see what your thoughts were. The alternator we are using is from a Dodge van late 80's early nineties I think, (it had a serpentine belt pulley) which I think they started using in the late eighties. Correct me if I am wrong. The only modification to the alternator was to disable the regulator otherwise it is factory. Let me know what you think.
