Sounds like you might have a Goodfry Model 37, built in 1937. Not sure from brief description. They are now collector's items and well out of the price range for everyday use. Some are sold on eBay for unbelievable prices. I knew a guy who had one in bad condition but as he had a daughter starting college, he sold it on eBay to pay for her first two years. They took a cruse with what was left over. The Official Goodfry collectors site is http://Goodfry.org/ Pookie ----- Original Message ----- From: "Michael Rigby-Jones" To: "Microcontroller discussion list - Public." Sent: Monday, October 03, 2005 2:06 PM Subject: Unusual alternator design? > I just repaired a rather cheap and nasty petrol (gas) generator for a family member. It's a small 2-stroke engine with a small 850Watt direct drive alternator, a mechanical governor on the engine and absolutely no electronic voltage regulation. Interestingly, the generator has no electrical connection to the rotor, e.g. slip rings. Instead the rotor has a single (but multi-turn) coil, the ends of which are connected by a couple of paralleled 1N540x rectifiers. The stator appears to have two windings, one connected to the output socket and one that provides the field and is simply connected to the output winding via a current limiting capacitor. I can kind of see how it works, I guess it must rely on residual magnetism to start up though. I can't imagine efficiency is particularly good though. > > I managed to get it working (the rectifiers were toast), but I was interested to know if this is a common or well known alternator configuration? Does it have a name? Google isn't telling me anything, though I'm probably not asking the right questions. > > FWIW Voltage (and speed) regualtion is predictably poor, though not quite as bad as I thought it would be (20-30volts from zero to full load, and about 5-8Hz change in frequency, nominal 240V 50Hz). A large DIY chain store were selling these recently for just 99UKP which would explain it's rather minimal design. > > Regards > > Mike > > > ======================================================================= > This e-mail is intended for the person it is addressed to only. The > information contained in it may be confidential and/or protected by > law. If you are not the intended recipient of this message, you must > not make any use of this information, or copy or show it to any > person. Please contact us immediately to tell us that you have > received this e-mail, and return the original to us. Any use, > forwarding, printing or copying of this message is strictly prohibited. > No part of this message can be considered a request for goods or > services. > ======================================================================= > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist