Servo Motors
Overview and Related Information

Overview and Features

Servo motors are specialized for high-response, high-precision positioning. As a motor capable of accurate rotation angle and speed control, it can be used for a variety of equipment.

Closed Loop Control by Which Motor Operation Follows the Command

A rotation detector (encoder) is mounted on the motor and feedbacks the rotation position/speed of the motor shaft to the driver.
The driver calculates the error of the pulse signal or analog voltage (position command/speed command) from the controller and the feedback signal (present position/speed) and controls the motor rotation so the error becomes 0.
The closed loop control method is achieved with a driver, motor and encoder, so the motor can carry out highly accurate positioning operations.

• An END signal communicates the completion of the positioning operation.
• An alarm can be output if there is an abnormality such as an overload, making it possible to communicate equipment abnormalities.

Click here for the AC servo motor structure

Position Control Using a Pulse Signal

The pulse signal is input by the controller. The rotation speed and stop position are then controlled according to the number of pulses.

Position Control Block Diagram

Speed Control by Analog Voltage

The analog voltage is input to control the rotation speed.

Speed Control Block Diagram

Torque Control by Analog Voltage

The analog voltage is input to control the torque.

Torque Control Block Diagram

Compact and High Power

The servo motor has a compact and lightweight design and outputs high power.

Speed - Torque Characteristic (200 W motor frame size: 60 mm)

Continuous Duty Region and Limited Duty Region

A servo motor controls the current according to the state of the load. Because of the efficiency and low heat generation of the motor, continuous operation is possible within the rated torque. Also, during acceleration/deceleration, the limited duty region is used to obtain a large torque, making it possible to decrease the positioning time.

Click here for how to read speed - torque characteristics

Wide Variable Speed Range

A flat, stable torque is generated from low to high-speed range, so that long-stroke positioning can be expedited.
The machine cycle is improved in testing equipment by quickly returning at high speed after slowly transporting the load at low speed.

Geared Type Also Compatible With Large Load Inertia

The servo motor has restrictions on the permissible inertia, but the geared type can be used to greatly increase the load that can be driven.