Generator Testing.

[guest22972]

My brother in law has a battle ship of a boat that has a generator on board that would be bigger than most off gridders have to run their whole property's.
It's gone Kaput and it's not the AVR.  He replaced that for no joy.

I'm wondering how to check the windings. Is it like a motor where you just check the Ohms across all the legs to make sure they are around the same or is there some different or better way to check if this thing has fried itself or what's going on.

I'm sure this is a simple question but the thing is I have never had to do it before.
Don't want to do it this time either actually.  Huge boat, tiny cramped engine room that will probably make me feel quite Claustrophobic. And joint pain from crawling in and out of a space designed for a Pygmy Child.

[EdDee]

Hi Glort,

First thing to check - If it is a brushed alternator, probably, would be to see if the brushes haven't stuck in their holders and are not contacting the commutator properly.... A common problem in less than ideal, damp environments... While looking at that, check the brush leads too for signs that one might have corroded off.....

Cheers
Ed

[32 coupe]

Check all windings to ground.
If it's in salt water windings going to ground are a common problem.

What type gen set ?

[dieselgman]

You can do very basic testing via a simple dismantle and inspection... you can often find major short circuits or wiring failures with a simple ohmmeter and visual determination. Each device will have its own specific procedure recommended by the manufacturer. To do a thorough confidence test, then you will need what is called a "Megger" or MegOhmmeter. The Megger will allow a high-voltage insulation test of the windings. This test is only recommended for the rare reconditioning and certification process because it can also "finish off" breaching a weak insulation area across the windings. It generally WILL show up any weak area that you might not otherwise be able to detect with other tools.

dieselgman