Gee Dave
that diagram is confusing....
it clearly shows + and - AND the AC symbol ( ~ ) under the V......
make me wonder just WHAT type of power the dynamo does generate ?
also for the 'test', it only talks about voltage NOT about current.....
Think of the dynamo as the generator rubbing against the bicycle tire when you were a kid. A magnet rotating around a coils of wire.... it produces Alternating Current. To generate Direct Current you need to involve a commutator which greatly complicates the device because brushes are involved and there are parts which wear out.
The illustration from the KUBOTA WSM can be misinterpreted but only because the writers were trying to make it simple. Like Ikea instructions. All multimeters will have red and black leads and most the + and - symbols to correspond.
Red and Black regardless if you are measuring AC or DC voltage, AC or DC current and then there are resistance and capacitance and frequency measurements all done with Red and Black leads. The illustration is just trying to show where the red and black leads go so that the tester is not confused.
For the purpose of testing the dynamo, it does not matter about its current output. If it will produce AC voltage in the right range it will drive current if a path for the current is provided.
If it cannot produce AC voltage in the specified range, it will not drive any current.
Doing the simple dynamo test early on in the diagnostic process can tell a lot about what needs to be fixed.
Note that in real life and on wiring diagrams for 2 and 3 wire dynamos, all the output leads are the same color because, with AC, it makes no difference in its operation. It is not like AC house wiring where there is a Hot wire and a neutral wire.
Dave
