AC Servo Motors

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 A rotation detector (encoder) is mounted on the motor and feeds the rotation position/speed of the motor shaft back 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 (current position/speed) and controls the motor rotation so the error becomes zero.

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 is obtained that 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.

Compact and High Power

The servo motor is compact and lightweight and outputs high power.

A Wide Variable Speed Range

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

Geared Type also Compatible with Large Inertial Loads

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


The servo motor has a rotation detector (encoder) mounted on the back shaft side of the motor to detect the position and speed of the rotor. This enables high resolution, high response positioning operation.

Light from the light-emitting diode (LED) passes through a position detection pattern on the slit disk and is read by the light-receiving element. Dozens of phototransistors are integrated in the light-receiving element. All of the patterns for absolute position detection depend on the rotation angle of the encoder.

The CPU is mounted on the encoder for analysis of the absolute position detection patterns. The current position data is transmitted to the servo driver via serial transmission.