直流无刷电机　Brushless dc motor

无刷直流电机由电动机主体和驱动器组成，是一种典型的机电一体化产品。由于无刷直流电动机是以自控式运行的，所以不会象变频调速下重载启动的同步电机那样在转子上另加启动绕组，也不会在负载突变时产生振荡和失步。中小容量的无刷直流电动机的永磁体，现在多采用高磁能积的稀土钕铁硼（Nd-Fe-B）材料。因此，稀土永磁无刷电动机的体积比同容量三相异步电动机缩小了一个机座号。

Brushless dc motor is composed of motor main part and drive,which is a typical mechatronic products.Since the brushless dc motor operate based on self-control operation,it will not start additional winding like overloaded and started synchronous motor under frequency control,also it will not produce oscillations and step out when the load mutates.Small-capacity permanent magnet of brushless dc motor,now more used by high magnetic rare earth neodymium iron boron(Nd-FeB)material.Thus,the volume of rare earth permanent magnet brushless dc motor is reduced by more than a frame size compared with the same capacity of a three-phase asynchronous motors.

微型直流电机　Micro motor

1.微型直流电机的效率一般都要高于其他类型的电机，所以达到相同的输出功率，直流电机的体积一般都比较小。对于安装位置有限的情况下，微型直流电机相对比较合适。

2.微型直流电机有个特点是电机可以根据负载大小，自动降速，来达到极大的启动扭矩。这一点交流电机就比较困难。另外直流电机比较容易吸收负载大小的突变，电机转速可以自动适应负载大小。

1,micro dc motor efficiency in general are higher than other types of motors,so achieving the same output power,the volume of dc motors are generally small.In the cased of limited installation position,micro motor is relatively appropriate.

2,The micro motor has a characteristic that motor can automatically speed down according to load size to achieve maximum starting torque,The ac motor is difficult regarding this point.Also dc motor is easier to absorb sudden changes of the size of load,and the motor can automatically adapt to the load size