What to look for in the Generator Head

[scherzoja]

When looking at AC generators in the 5kW to 8 kW range, how much scrutiny should be given to the generator head?

Generator vendors give detailed information about the engine side of the genset in their spec sheets, but not much info regarding the electricity-producing side. Are the generator heads the same? Why are more generator heads not water-cooled, like the old Entec West gensets (bought by Mastry, then removed from the market).

What should one look for in the design of the generator head when considering an AC genset?

Is the generator head also called an alternator or is that term specific to the alternator on our engines that produces AC current, then rectifies it to DC?

Setting aside space/cost considerations, does a direct-coupled generator head (i.e. NL, Phasor) have any advantages over a belt-driven one (i.e. NextGen)?

Thanks y'all