The hypothesis states that if humans do not learn a foreign language before a certain age, it becomes impossible to learn the foreign language like a native speaker.
【简答题】有一台三相线绕式异步电动机,用它拖动位能性负载,已知电动机技术数据如下:P N =60KW,n N =577r/min,,I N =133A,E 201 =253V,I 2N =160A,λ m =2.5。试求: (1)电动机以转速n=120r/min下放重物,已知负载转矩T L =0.7T N ,计算电机转子回路每相应串入多大的电阻? (2)电动机从额定转速的电动状态采用电源反接进行反接制动,以...