Exercise bike alternator

November 12^th 2007 Good morning Welcome back to another week of Brian's Morning Newsletter. The Las Tusas Ranch, home of alternative energy research, where you and I can get an edge on the future. I love this stuff, I really do. Well I done did it. Our pedal powered living room computer is up and running. Instead of the big old automotive generator I was convinced to use a small alternator. We scavenged one cute little alternator out of a Mazda B2000 pickup from over in our shrinking automotive graveyard. The darn thing had the strangest wiring I've come across. One heavy battery terminal, one medium gauge wire which, according to the e-book I found at http://www.autoshop101.com/forms/allinone.pdf , goes to a battery thyristor, the other two go to the PCM, sheesh. I hoped going with an alternator was going to be easier to wire than the generator. I had all these wires to figure out where to put. I noticed that if I applied 12 volts momentarily to any of the three wires while the battery cable was connected, the alternator would get very hard to pedal, hence it was working. Everything worked out by mid-morning. Basically, the way either a generator or an alternator works is through rotation opposing magnetic fields continually crossed. From Wikipedia: A Dynamical Theory of the Electromagnetic Field which was written in the year 1864, is the third of James Clerk Maxwell's papers concerned with electromagnetism. It is the paper in which the original set of eight Maxwell's equations first appeared. The concept of displacement currentOn Physical Lines of Force was utilized for the first time in order to derive the electromagnetic wave equation. I tried several wiring setups in an attempt to mimic what the schematic seemed to suggest the PCM (power-train control module, aka a modern automobile's brain) was doing to control the alternator. I finally had success by connecting the input to the output, smiles. I love it when I can bypass sophisticated electronics with a wire nut. Anyway, I can't imagine pedaling the battery to death by over charging. We don't need no stinkin' PCM! I haven't checked the output current, but with the two sense wires jumpered, the alternator kicks out plenty of power, evidenced by the effort required to pedal and the reading on the volt meter. Yesterday evening we ran the computer for several hours on pure battery power. I also did most of my usual posting to the half dozen Internet groups I belong to on on the pedal powered PC. At the moment the system consists of 12 volt battery power generated via pedals through the alternator which in turn is stored in a deep cycle battery then converted to 115 volts AC for the computer and screen by a 1000watt inverter from an old ambulance. The battery power held at 12.44 volts, for better than four hours, running a 1.2mhz AMD PC with a 14inch LCD screen. Family members took turns pedaling for a total of 15 minutes. Of course, the big deep cycle battery is new and already had a good charge. I'm watching the volt meter to see when I need to start pedaling again. Indeed, after three hours, the voltage began to drop at which time I merrily mounted the exercise bike and pedaled until I was out of breath with seriously aching legs. At the moment I have only one of the two deep cycle batteries I bought this Summer for our solar powered Campout. But it looks like this system is going to work just fine. The real the trick, and pardon the pun, turning point, was having a friend pedal the bike while I used a side grinder to make a vee groove in the steel flywheel. This feels really great. Every little bit helps The bike is great for showing people how much energy (horse power) an automotive alternator takes from an engine to power lights, stereo, and other accessories. I can see too that it will demonstrate effective belt tension very nicely as a belt which is too tight will be more difficult to pedal and one that is too loose will slip. We have a slew of fine letters this morning. Thanks to everyone for reading and writing. Sincerely, Brian Rodgers