Total copper loss in parallel operation of dc generator
Just because there are two DC generators running in parallel, you can't assume that they are equally delivering the same power to a load. Therefore you have to treat them as individuals. Each generator will have its own feedback system and if one inherently wants to generate 100 mV than the other, it will supply the higher voltage and the other will "back off" on the basis that it thinks it is supplying too much voltage. Result is: 1 generator supplies nearly all the power to a given load.