For a specific genset, run in that way the maker's data  will be true. Well, we hope so.

But do not assume that the same factors will apply to another model, or any similar looking one from a different makers, or worse one using a different magnetic technology internally., or even the same alternator but  not driven under those test conditions.



If you want a set of design rules that will work with any generator of given wattage chosen at random, the variation in performance you have to accommodate  is considerable, and a further confusing factor is that  given that output power may also be considered as a continuous or a  short duration value as well. It is also important to say that unless it has been designed to allow it, you cannot even assume it is safe go from say 10% of full load to 100% of load without intermediate steps, without the machine stalling.



As an aside all internal combustion engines need a flywheel of some kind, or they do not run.  It is usually at the take off end of the crankshaft, and may be part of the gear train if the alternator is multipole and  not direct drive. In a direct drive  induction set the armature is often performing the flywheel function. If you want a nifty compromise between acceleration and torque/speed variation then a dual mass flywheel may be used, but this is more use for road vehicles, and energy saving inverter type generators where the revs vary a lot, which are generally smaller than it sounds like your application will need.  (largest being sub 100kVA when I last looked at this for a project). Something that has come from the road user in the  last 30 years or so,  is that you now commonly see turbo diesel engines used on gensets to give a wider range of power at near constant speed.

M.

For a specific genset, run in that way the maker's data  will be true. Well, we hope so.

But do not assume that the same factors will apply to another model, or any similar looking one from a different makers, or worse one using a different magnetic technology internally., or even the same alternator but  not driven under those test conditions.



If you want a set of design rules that will work with any generator of given wattage chosen at random, the variation in performance you have to accommodate  is considerable, and a further confusing factor is that  given that output power may also be considered as a continuous or a  short duration value as well. It is also important to say that unless it has been designed to allow it, you cannot even assume it is safe go from say 10% of full load to 100% of load without intermediate steps, without the machine stalling.



As an aside all internal combustion engines need a flywheel of some kind, or they do not run.  It is usually at the take off end of the crankshaft, and may be part of the gear train if the alternator is multipole and  not direct drive. In a direct drive  induction set the armature is often performing the flywheel function. If you want a nifty compromise between acceleration and torque/speed variation then a dual mass flywheel may be used, but this is more use for road vehicles, and energy saving inverter type generators where the revs vary a lot, which are generally smaller than it sounds like your application will need.  (largest being sub 100kVA when I last looked at this for a project). Something that has come from the road user in the  last 30 years or so,  is that you now commonly see turbo diesel engines used on gensets to give a wider range of power at near constant speed.

M.