I have an inverter generator that I made which uses a GM 10SI alternator(One Wire). Needless to say the regulator became faulty. I decided to remove the v-reg and use the attached circuit instead(the upper circuit). All components are as described, tested as NOT faulty, and wired properly. I live in a remote area where parts are not readily available, hence why I am making one. I removed the old v-reg and ran a wire from the diode trio which use to connect to it, and the wires from the field(brushes), and a ground wire. I connected the circuit up as follows: diode trio output to the top rail of the schematic, the remaining field wire to the collector of the trans with the diode, and the ground wire. Nothing happened. So I also connected the battery and trio output together and tried it again.....and as soon as the engine started the alternator was putting out a lot of voltage/current. It was reading 16.4V. Too high. I did not have a 13v zener, so I used 2 in series. 9.1V & 3.6V.