24-03-2022, 03:22 PM
(22-03-2022, 09:55 AM)Stuart Giles Wrote:
(21-03-2022, 11:23 PM)Ivor Hawkins Wrote: Now that looks neat, excuse my electro dyslexia but would that work with a six volt system?
well........... You could run it at 6V but it would give the regulator a really hard time. The main component in the regulator for a permanent magnet alty is a thing called a Zener Diode. Basically these have a set Zener Voltage 14.5 ish volts for a 12v system, or 7.8 ish volts for a 6 volt system. When the incoming voltage exceeds whatever the Zener voltage happens to be, the Zener diode sends it to earth, so immediately the voltage will drop below the Zener voltage and charge gets forwarded to the battery. Then when the voltage rises, once again it's earthed by the Zener diode. You can see why all the permanent magnet alty regulators have fins on them, have instructions that they should be in free air and/or should be bolted to a metal surface etc. It's because they are sinking power. Giving the alty setup above a quick test last night, the alty was pushing out almost 15V AC at not especially high revs; a regulator for a 6V system would function with this alty, but it would be working really hard and I think may well not live for very long.
Thanks Stuart, I seem to remember a Zenor diode on the front of my old BSA motor cycle, so it must be established technology which works...rather than bugger up my regulator I’ll stick with the standard dynamo for the time being, but I like the conversion...