英语语法分析

Electric machines are composed of stator and rotor.

电机是由定子和转子两部分构成的。

Both stator and rotor are made of ferromagnetic materials.

定子和转子都是由铁磁材料构成。

Thus it is necessary to identify stator resistance on-line.

因此，非常有必要对定子电阻进行在线辨识。