一、引言现在社会上所有的发电机,实际上不是发电机,确切的说应该叫它换电机。因为要得到电能就必须付出等能机械能:换句话说,现在人们所用的电是用机械能换来的。所以说现在社会上所用的起电工具应该叫它换电机。发电机的“发”就应该用自发的意思。对它不投入任何能量能自然输出电能的才叫发电机。 I. Introduction Nowadays, all the generators in society are actually not generators, and should actually be called motors for alternation. Because of the need to get the energy we have to pay for mechanical energy: in other words, people are now using electricity in exchange for mechanical energy. So now the power tools used in society should call it for the motor. Generator “hair ” should use spontaneous meaning. It does not put any energy to output electrical energy is called generator.