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

[capn_billl]

One thing I'm going to seriously look at on my next generator is how the head is cooled.

My last Northern lights generator was air cooled with large open vents on top directly under the exhaust hose.

A leaking exhaust hose resulted in salt water being drawn into the electrical windings, and destroying them. It is non reparable as the bolts to remove the head are inside the windings, and buried under rust, and corrosion.

[goboatingnow]

Most gensets use stock AC alternators and hence these are air cooled. Only a few ( like Fischer panda) build custom water cooled units.

AC generators all use alternators. ! The teen generator applies to both AC and DC types.

I’ve had newer sophisticated types like the FP , but the FP engine systems are crap and older air cooled units that were 25 years old and still running ( my Maze genset still had the original radiator fan inside the housing !!! )

A curse on all generators really.

[ItDepends]

Most of the small diesel engines used in the size generators you are talking about are incredibly reliable machines if installed properly and well cared for. Almost all the problems generators have come from the electrical side. And most of those problems come from poor cooling and/or salt water contamination.

Most AC generators do NOT use stock AC alternators, some are not even really alternator based, but are actually armature based units. They are brand specific including the voltage control.

There are two different kinds, the fixed speed where the rotation speed of the engine is fixed and sets the frequency of the power (usually 1800 RPM for 60 Hz) and variable speed units which convert variable voltage and frequency output to the desired power specification. There are pluses and minuses to both.

ALMOST all will be air cooled, although you can find some permanent magnet types that are water cooled. WhisperPower makes those, and I am sure there are others.

So much of the choice really depends on how you will use it, and how often, how much space you have to install it, and how clean and dry the space is. Are you weight sensitive? And who has part availability where you will be cruising.

[goboatingnow]

Fisher panda as I mentioned are one of the few doing water cooled generators ( not permanent magnet either ). Their generator heads are good , the rest is rubbish imho.