Brush motor low cost, simple structure, large starting torque, wide speed range, easy control, need to be maintained, but easy to maintain (change the carbon brush), electromagnetic interference, the use of the environment has requirements, usually used for cost sensitive ordinary industrial and civil occasions.
Brushless motor small size, light weight, large output, fast response, high speed, small inertia, stable torque and smooth rotation, complex control, intelligent, flexible electronic commutation mode, can be square wave or sine wave commutation, motor maintenance free, high efficiency and energy saving, small electromagnetic radiation, low temperature rise long life, suitable for various environments.
Ac servo motor is also a brushless motor, divided into synchronous and asynchronous motors, the current motion control is generally used synchronous motor, its power range is large, the power can be very large, large inertia, the highest speed is low, the speed decreases with the increase of power and uniform speed, suitable for low-speed smooth operation
The rotor inside the servo motor is a permanent magnet, the driver controls the U/V/W three-phase electric field, the rotor rotates under the action of this magnetic field, and the encoder with the motor sends the feedback signal to the driver, the feedback value is compared with the target value, so as to adjust the rotor rotation Angle, the accuracy of the servo motor is determined by the accuracy of the encoder (line number).