Join Date: 01-11-2005
Location: Kansas Citeeeee, MO USA
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Re: Rewinding Stator
50 volts? You haven't seen anything yet! That's at idle under an open circuit. Peak voltage is higher. You should try hitting redline with a stock stator unconnected. You should see several hundred volts peak to peak with an oscilloscope.
Our regulator/rectifiers use shunt type regulation. What is not used is shorted back to the coil. When your coil is plugged into the regulator, you will only see battery volts. Unplug it and you can have some fun with high voltage.
Stock wiring uses 17 gauge with 59 turns on each pole. I've tried 14 gauge and was able to squeeze 20 turns on each, but to maintain battery voltage required nearly 2,000 rpm. And it gave me over 30 amps on each phase, or 50 amps through the wiring harness. If the battery was discharged at all, the wiring harness would get very hot. Since the rpm's would get low frequently, you can bet connectors melted. My 14 gauge stator failed during the first warm days after winter. And melted the solder inside my stock regulator/rectifier.
I'm currently using 16 gauge, but am going back to 17. These stators put out too much power in such a small area that they burn up.
So why the unusual high voltage? We use old technology shut regulation. That's because our charging systems do not have a field excitation like a car alternator. This is to make our charging systems much smaller. You can imagine the size of a slip ring/brush assembly would add. So why not a switching voltage regulator? Transistors can switch very fast with high rpms, but have a problem doing that with high voltage. That's why our regulators have an SCR inside them to clamp down on the high voltage peaks. Its cheap and easy to make these. At all times, about one horsepower is being shorted back to the coil. I don't see Honda spending much more money on our charging systems.