Re: [Amel Yacht Owners] Onan Generator

Craig Briggs

Hi Danny,
Actually it's a little different than your engine alternator. That does indeed have a direct 12v excitation wire that energizes when you turn the key on. On the Onan (or other gensets), the AC generation is dependent on having a residual magnetism begin the excitation process.  There isn't a separate 12v battery circuit. The residual magnetism can be lost with a long period of non-use, a shock load on the system that kills the engine, which is likely Heinz's case, our faulty brushes.
Cheers, Craig SN68

---In amelyachtowners@..., <sailorman.ds@...> wrote :

Hi Heinz,

It is the same way as your engine mounted alternators have to be excited. Properly wired it happens when you turn the start key on. I guess it should work the same with the gen set. With your alternator if the exciting circuit is faulty the excitation can occur by reving your engine. This result tells you the alternator is OK and it is the excitation circuit where the fault lies. So perhaps your problem is in the excitation circuit



SM 299 Ocean Pearl

On Fri, 30 Nov 2018 at 09:17, 'Stutenbaeumer.Berlin' heinz@... [amelyachtowners] <amelyachtowners@...> wrote:

Thanks fore the anther but how do I re-flash a generator?


Am 29.11.2018 um 10:41 schrieb sangaris@... [amelyachtowners] <amelyachtowners@...>:



I believe your Onan has a "No AC Output" shutdown switch that would shut it down as you describe. 
With any luck, you may simply have to re-flash the generator to solve the problem. 

If that doesn't work you'll want to check the circuitry on the generator for winding continuity, resistance through the brushes, etc. (I assume you have fixed the short circuit, of course, and checked breakers.)

Let us know what you find.
Cheers, Craig SN68

---In amelyachtowners@..., <mcerdos@...> wrote :



I think you are dealing with a couple of issues.


Since you had an electrical short did you check the master circuit breaker on the generator?


Is the fuel supply sufficient? Are you getting enough fuel from the electric pump? Is the fuel clean? The most common cause of a diesel engine shutting down once it has started is lack of fuel. Believe it or not, it is very hard to stop a running diesel engine.





With best regards,





Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - Santa Marta, Colombia


From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, November 29, 2018 7:55 AM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Onan Generator



I would have yesterday with Onan generator switched on a short circuit in an electric line.
Then the generator went out.
The generator starts since then briefly, then goes out however immediately again.
Only if I increase the speed of the generator manually after the start, it remains on, but does not generate electricity.
Somebody knows advice.
I am grateful for each suggestion
Super Maramu 2000, 292 Panama

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