一般电动机主要由两部分组成：固定部分称为定子，旋转部分称为转子。另外还有端盖、风扇、罩壳、机座、接线盒等。
General motors are mainly composed of two parts: the fixed part is called stator and the rotating part is called rotor. In addition, there are end covers, fans, covers, bases, junction boxes, etc.
电动机的工作原理是建立在电磁感应定律、全电路欧姆定律、和电磁力定律等基础上的。当磁极沿顺时针方向旋转，磁极的磁力线切割转子导条，导条中就感应出电动势。电动势的方向由右手定则来确定。因为运动是相对的，假如磁极不动，转子导条沿逆时针方向旋转，则导条中同样也能感应出电动势来。在电动势的作用下，闭合的导条中就产生电流。该电流与旋转磁极的磁场相互作用,而使转子导条受到电磁力（安培力），电磁力的方向可用左手定则确定。由电磁力进而产生电磁转矩，转子就转动起来。
The working principle of the motor is based on the law of electromagnetic induction, Ohm's law of the whole circuit and the law of electromagnetic force. When the magnetic pole rotates in a clockwise direction, the magnetic line of force of the magnetic pole cuts the rotor guide strip, and the electromotive force is induced in the guide strip. The direction of EMF is determined by the right-hand rule. Since the motion is relative, if the magnetic pole does not move and the rotor guide bar rotates in the counterclockwise direction, the electromotive force can also be induced in the guide bar. Under the action of electromotive force, current is generated in the closed conducting bar. The current interacts with the magnetic field of the rotating pole, which causes the rotor bar to receive the electromagnetic force (ampere force). The direction of the electromagnetic force can be determined by the left-hand rule. The electromagnetic torque is generated by the electromagnetic force, and the rotor rotates.