Quote:
Originally Posted by Cheechako
Most marine ac generators run at 3600 rpm. That's screaming.
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Most marine generators run at 30 times the desired frequency. The ones that run at 60X are not really that popular. They mainly appear in low end
low power units. The typical quality marine
generator runs at 1800/1500
RPM for 60/50Hz output.
The idea that a DC genset is "self optimizing" is a bit of a myth in my opinion. Fixed speed 3 cylinder diesels last a long time. If you are worried about light loading then put a load on it. It does not change
fuel consumption much to load a genset to 30% of kW output which is enough to keep the
engine hot. It's pretty simple to build up a 200-300A mains powered
charging system that runs from a genset or
shore power.
It's pretty hard to beat the
reliability of a shaft connected AC generator. Some DC units have belt drives and somewhat complex
engine speed control circuits. And a lot of DC units have one or two cylinder shake-a-lot engines.
You will find people with bad AC genset experiences. But that has more to do with the vast market share they enjoy. There are hundreds of thousands in
service. If they were terrible there would be a lot less of them.