The main purpose of servo motors is to control the displacement and operation of the motor equipment. As the commonly used motors, servo motors enjoy the advantages of precise positioning, which results in a wide application.

1.The Main Functions

(1)The servo motor itself also has function of generating a pulse current. Each rotation of an angle will emit a corresponding number of pulses that can be used by servo motors to form a response and a closed loop. In this way, the system can know the number of pulses it has already sent to the servo motor and how many pulses it has already received at the same time, through which it can control the rotation precisely and the positioning precision can reach 0.001mm.

(2)DC servo motor can be divided into brushed motor and brushless motor. In terms of brushed motor, it has edges in low cost, simple structure, large starting torque, wide speed range and easy control. But it needs to change carbon brushes. Although the change has no difficulty, it will cause electromagnetic interference and is burdened with environmental requirements. Therefore, it can be applied in common industry and civil applications that are sensitive to the costs.

(3)While brushless motors are featured by small size, light weight, great output, fast responding speed, small inertial, and stable rotation and torque. It is complex to control, but it is easy to be intelligent. Commutated by square wave and sine wave, the electronic commutation is flexible. The motor is free from maintenance and enjoys a high efficiency, low working temperature, subtle electromagnetic radiation, and a long service time. Besides, it can be applied in any environment.

(4)The AC servo motor can be divided into a synchronous motor and an asynchronous motor. Currently, the former is often applied in motion control. It has a large power range and can work with large power. With low maximum RPM and inertial which will rapidly decreases with the increase of power. Therefore, it is used in what requires low speed and stable operation.

2.The Advantages

(1)Having extraordinary response speed, the servo motor provides a large torque in the point-to-point fast positioning motion occasion, which makes the system have a extremely high dynamic response and greatly exceeds the limit of the traditional stepping system.

(2) The servo motor remains in the range of its rated speed range and belongs to constant torque output. And it has a variety of feedback adjustments to ensure the running accuracy of the servo motor and output torque.

(3)The Main Applications

*Machinery industry:machining centers, CNC punching machines, bending machines, shearing machines, PLC program controllers, etc.;

*Printing industry:drying board machine; printing machine, offset printing machine, rotary machine, laser phototypesetting, proofing equipment, automatic punching and inkjet printing machine, etc.;

*Medical industry:monitor, B-ultrasound machine, CT control box, electrocardiogram ( EEG) tester, X-ray machine, etc.;

*Food industry: sterilizer, homogenizer, labeling machine, can making machine, flow control instrument, sealing machine, etc.;

*Rubber tire industry: steel wire belt ply production line, inner liner extrusion production line, steel wire calender, etc.;

*Elevator industry: door control, floor control, etc.