Shaft drive generators

[Mako]

What experience does anyone have with using a shaft-driven (PTO usually) generator? With today's automatic frequency controllers PWM, maintaining correct engine rpm isn't as critical as it used to be.

A nice 5kW unit isn't so expensive and in reality seems more practical while underway than running a couple of large frame alternators through a 5kW inverter.

Or so it seems...

 

[DDW]

Really just the same thing, isn't it? On my sailboat, I run a 7 KW 24V alternator driven by a shaft. It would be a little more efficient to run a 3 phase high voltage alternator through a AC -> AC converter (like the Honda generators) but you'd have to build it yourself. Mastervolt used to offer such an arrangement, don't know if they still do. Any of those schemes converts the AC alternator output to DC, chops it, and recreates the AC waveform. Added efficiency comes from a high voltage alternator, as the windings can be a lot smaller and the diodes more efficient.