B 7100 gear drive early 80's Kubota. I'm getting a reading on my voltmeter of 8 volts from the output side of the rectifier. The dynamo is putting out voltage, 15 volts AC or so at about 1000 rpms if I recall correctly. I put one lead from my volt meter in the output of the rec, and one on the neg. post of the battery. (Putting the lead on the positive post didn't show as high a reading). Any help on this? What else should I check? I'm trying to get my charge system to function so I can run my lights and such. I have the dynamo type that's right behind the fan. The light switch doesn't effect charge rate, its not that kind of set up.
Thanks for any help.
David.
Does your dynamo have 2 wires or 3 coming out of it. If only 2 then you are correct and the light switch is not involved with the charging circuit.
Disconnect both wires from the dynamo. Connect an AC meter to the ends of the wires coming from the dynamo. Start the engine set throttle at full speed. If your dynamo is good you should get a reading of above 30VAC. If you have 3 wires coming from the dynamo the test is slightly different.
Over 43 volts between the brown and white wires and 30 or more volts between the brown and yellow wires.
If the voltages are within spec then you should test the rectifier.
I am a little concerned about when you state---
I put one lead from my volt meter in the output of the rec, and one on the neg. post of the battery. (Putting the lead on the positive post didn't show as high a reading). You should not get any reading between the output of the rectifier and the positive post of the battery. If you do get a reading it indicates a high resistance in the circuit. Such as dirty or corroded battery terminal and clamps, or bad wires that are corroded under the insulation. Could also be a defective switch.
