running a generator with my own boat motor ??? Please read and give me some ideas!

If I had designed the generator I would have regulated the voltage by controlling the magnetisation current, as in any DC alternator. I haven't disassembled any AC generator but I hope that at least some are designed that way. The frequency comes from the rpm so that would vary somewhat.

Why not connect the generator to the diesel engine via a clutch and belt transmission so the generator runs at the design RPM when the engine runs at a suitable speed, e.g. 1500 rpm? When not under way this setup wouldn't differ very much from the usual diesel generator configuration. If you need the AC power when cruising, you have to accept whatever cruising speed you get at the RPM needed for the generator.

I think it would be nice to have a 3-phase high power AC network in the boat, mostly for the kitchen but also for electric power tools. When under way I wouldn't need more AC power than what a small inverter can provide.

Erik

 

Nearly all small AC generators rely on a single capacitor to change the cos phi of a secondary winding to magnetize the rotor, the capacity and number of turns are calculated for a single rpm only.
Although a clutch/belt setup is possible, an electronic switch is necessary to disengage the generator when the rpm exceeds a set value, otherwise a lot may go up in smoke if the clutch is left engaged by accident.

The alternator/inverter solution is cheaper and has no such problems.

 

I can't imagine any reason for Three Phase Power on non-commercial vessel, unless you happen to have a LOT of Big Power AC Motors that you need to turn. Single Phase will do everything one would need in the Galley, and I have never heard of a Three Phase Hand Power Tool. If you absolutely needed some Three Phase Power, just invest in a FreqDrive and make it from Single Phase.