3000W Chinese Gensets Info.
professor95 wrote: EDIT ADDED 45/5/2013- When this thread started in March of 2005, I never expected to see it survive this long or amass the quantity of information that has been shared here. In...
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The rated capacity of any electrical generator will be de-rated as the temperature of the windings rises. This applies to alternators in hot engine bays, generators whether in open or enclosed, and hydro-electrict power house generators.
Typical cold amp ratings are at 25C (77F). Finding de-rating information about alternators is hard because no-one seems to want to talk about it. The de-rating could be as high 20%, or higher, when the temperature reaches 100C (212F).
There is also a loss with increase of altitude by both the engine and the alternator windings. Thinner air means less efficient engine and less efficient winding cooling. Industrial generators actually specify this info....typical: 3% per 18F above 77F, and 1.3% per 328 ft over 656 ft. Example: a 3500 Watt generator running in the shade with outside temp of 113F at 1610 ft would be derated by 6 x 3.9 = 23% or only 2695 watts.
Onan rates the Marquis Gold deratings at 3.5% for each 1000 ft above 5000 ft, and no derating for temperature below 120F. Pretty conservative. Knowing the desire for good numbers, I bet the cheaper generators are rated generously. http://www.onan.com/pdf/rv/a-1425.pdf
Imagine the difference of taking an open frame generator and adding insulation, or a box, around it.
For the most dependability, buy a generator that is designed to be in enclosure.
OT comment: A friend of mine moved to Denver, from Calif, and had to upgrade the CPU cooling on his computer (he's a gamer and runs his stuff hard).
Typical cold amp ratings are at 25C (77F). Finding de-rating information about alternators is hard because no-one seems to want to talk about it. The de-rating could be as high 20%, or higher, when the temperature reaches 100C (212F).
There is also a loss with increase of altitude by both the engine and the alternator windings. Thinner air means less efficient engine and less efficient winding cooling. Industrial generators actually specify this info....typical: 3% per 18F above 77F, and 1.3% per 328 ft over 656 ft. Example: a 3500 Watt generator running in the shade with outside temp of 113F at 1610 ft would be derated by 6 x 3.9 = 23% or only 2695 watts.
Onan rates the Marquis Gold deratings at 3.5% for each 1000 ft above 5000 ft, and no derating for temperature below 120F. Pretty conservative. Knowing the desire for good numbers, I bet the cheaper generators are rated generously. http://www.onan.com/pdf/rv/a-1425.pdf
Imagine the difference of taking an open frame generator and adding insulation, or a box, around it.
For the most dependability, buy a generator that is designed to be in enclosure.
OT comment: A friend of mine moved to Denver, from Calif, and had to upgrade the CPU cooling on his computer (he's a gamer and runs his stuff hard).
