Ok, so I've finally got an alternator for the lawnmower genny. A Delco Remy 55A one, with internal regulator.
Have taken the thing apart, cleaned it up. Regreased the bearings (couldn't be bothered to replace them). The voltage regulator I removed. One of the brushes I grounded, the other one I rewired to the 'D+' terminal that became available after the regulator was removed. So, now I've got full access to the rotor field. The Homepower mark8 rotor fieldcontroller connects to it. Will start building this controller next weekend.
The field draws a full 3.6A when connected to 12V. With full field, when I give the alternator a spin by hand, it generates 3VDC! Was amazed of that high voltage at this low RPM. On the other hand, at the same time, the field was consuming 3.6A at 12V = about 40W...
BTW, as I took out the rotor, the brushes jumped out. It took me quite a while (about an hour) of tinkering with pieces of string and stickytape, to try to hold the brushes in, that I realized there was a little hole in the alternator case. Its purpose is to put a pin through so the brushes remain in place as you re-assemble the alternator. Just took me about an hour to find this out. Doh...
Some pix of the cleaning, refurbishing and modifying are below. Int the last picture you can see the parts that were leftover: the voltage regulator (white) and the field-rectifier (black).
The only thing I don't like about this alternator: it doesn't have a key! The pulley has to transfer all torque to the axle by means of clamping pressure. Yuck!





