DC servo motors consist of stators, shafts, windings, bearings , encoders, encoder cables, motor cables and the rotor made of laminated silicon steel laminations fixed on the motor shaft.
Dc servo motors mainly relay on pulse to locate, basically as the servo motors receive a pulse, the pulse will spin an angle correspondingly to achieve displacement. Since the servo motors have issued a pulse function, servo motors will correspondingly send some pulses when they rotate a certain angle so as to form echoes called closed loop to accept the formation. This way, the system is able to know how many pulses sent to the servo motors and the number of pulses coming back at the same time. So, we can accurately control the rotation of the motors in order to achieve accurate positioning, which can even reach 0.001mm . Check the picture, you may understand the working principle of dc servo motors more easily.
DC servo motors especially denote DC brushed servo motors with high cost, complex structure, high starting torque and wide speed range, which are easy to control. And they also require maintenance, but maintenance is not easy work for difficulty of replacing the brushes. And the two types of dc servo motors have similar working principle and construction. Yet DC servo motors will produce electromagnetic interference and can only work in certain sites. Generally, they are used for cost-sensitive industrial and civil applications.
DC servo motors are not like brushless DC servo motors with small size, light weight, large output, fast response, high speed, small inertia, smooth rotation, torque stability, electrical power and no limitation which are easy to implement intelligence. And brushless DC servo motors have flexible electronic commutation, square wave commutation or sinusoidal commutation, Maintenance-free and have brushless without loss. The brushless DC servo motors have high efficiency, low operating temperature, low noise, very small electromagnetic radiation long life-span and can be used in various environments.