T&T: Gensets

[Allen, Harris]

The factory rep told me that genset life is shortened by how many times
it

is started up and shut down. My oil consumption now is probably the
result of

the previous owners not loading the genset enough. Not loading the
genset

also causes reduced engine life.



Having been in the generator business for many years I have a few
comments to post. I would say that the average life span of a marine
generator is about 5,000 hours. As a general rule  they don't wear out,
they blow up! This is usually the result of an impellor going bad and
the rusty overheat switch failing or something similar. Exhaust systems
not properly done is a huge problem leading to the generator choking
it's self to death. I was on a sportfish yesterday that had just
undergone a $750,000 refit, the exhaust on the brand new Onan had one
180 degree fiberglass bend and two 90 degree bends in addition to the
muffler, not to mention the 20ft run to the transom. Any guesses on the
lifespan of that puppy? The other side of the coin is the 137ft Perrini
Navi that I did a valve job on one gen and a short block on the other,
both with 28,000 hours. Generator loading is an issue as well. They like
to be loaded at 80% and no less than 50%. The mega yacht solution is to
have 2 smaller sets with auto paralleling or an auto load bank. The
trawler crowd has the option of using a smaller gen in conjunction with
an inverter that will parallel with the generator for peak shaving.



Regards,

Harris

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