Re: [Amel Yacht Owners] Generator load, carbon buildup, etc.


eric freedman
 

Craig,

My Onan is a MDKAV model and I don’t have the slightest idea how many rpm the 3 cylinder Kubota is running at. However it puts out 220-230 volts at 50 cycles.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Saturday, March 17, 2018 10:40 AM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Generator load, carbon buildup, etc.

 

 

Hi Eric,

Sorry, didn't mean to sound cheeky. I think your Onan has the same Kubota 3 cylinder engine as my Northern Lights, but whereas mine operates at 1800 rpm (I've got it set for 60 Hz 110v) I see the spec on the Cummins Onan says it operates at 2900 RPM (that's the Onan QD 6/7.5/8 KW Generator that seems to be their current model). I think I just stepped out of my knowledge level - how do they get 50Hz at 2900 rpm?

Cheers, Craig SN#68



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

Craig,

Of course the generator does not have a variable speed.

What I meant is that we usually do not run the genset under enough load.

80 percent of the output of a 7.5 kw genset, I believe should be a usage of about 27 amps.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...
Sent: Friday, March 16, 2018 9:49 AM
To: amelyachtowners@...
Subject: RE: [Amel Yacht Owners] Black Smoke From Volvo Penta Engine Exhaust

 

 

 

Hi Eric,

You bring up an interesting point when you say you had the same carbon build up problem in your genset exhaust elbow, caused by not running at high enough rpm's. Unless you've got a variable speed genset, it always will be running at a high rpm (3000 or 3600 depending on Hertz), so rpm may not be the only issue. Isn't it low load that's the issue? 

So when Yanmar says to run the engine way up, no doubt they're assuming it will be in gear and will present a full load from the propeller. I think the genset analogy would be to load it with not just battery charging, but also get the Admiral to run her hair dryer, make toast, wash clothes and iron your shorts. Not a bad regimen, actually.

Sound about right?

Cheers, Craig SN#68 Sangaris

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

Hi,

I had his problem with my genset. It is caused by not running a diesel at about 80% of its redline. Diesels like to work hard. Our diesels are not run that hard so is the main engine.

Yanmar suggests to run the engine way up. In my case 3000 rpm for 15 minutes  a few time a day

This blows the carbon out of the turbo and the exhaust system.

 

 

The carbon is usually glass hard.

However if the elbow is not perforated due to corrosion, I would try  to break out the carbon.

You might try something like a dremel tool with a hard steel bit, or even better a carbide bit ,or a small cutoff disk. Being that they have ordered a new elbow for you,  you could go Medieval” on the elbow.

 

On eBay there is a fellow that makes beautiful Yanmar elbows out of stainless steel. They are much better than the factory unit. Possibly he makes elbows for your engine.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

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