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Old 05-18-2016, 08:50 AM   #15
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City: Taunton, Mass.
Country: USA
Vessel Name: Rise & Shine
Vessel Model: Prairie 29
Join Date: Jan 2015
Posts: 73
We run into lightly loaded diesels a lot in the generator world, particularly at hospitals which exercise their generators weekly, but usually without putting any load on them. So the machine runs at 1800 rpm for 30 minutes, but at no load. After a year, there are ~25 hours on the machine but no load.

Generally we put them against load banks once per year and take them up to 80% power (remember, that's 80% of the "Emergency" rating, which is often as much as 20% higher than the "continuous" rating) for four hours.

Typically it rains black soot & carbon for 5 to 15 minutes, then the exhaust cleans up, and the engine sounds better. Then it sings along for the rest of the four hours.

Some of these machines are 30+ years old (hospitals spend their limited dollars on things that make people healthy, not new shiny generators).

Lesson: Running them hard is (a) beneficial (b) not important in terms of wearing them out and (c) important if the engine is often lightly loaded.

...just my two smallest-unit-of-currency's worth


John R. Stewart
"Rise 'n Shine" Prairie-29, (formerly) "Driftless" Albin-25, Hull number 737
Dighton, Massachusetts, USA
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