What is a motor encoder？

The motor encoder is a rotary encoder installed on the motor, which provides a closed-loop feedback signal by tracking the speed and/or position of the motor shaft. The monitored parameters are determined by the type of application, and can include speed, distance, RPM, position, etc. The application of specific parameters controlled by encoders or other sensors is called closed-loop feedback or closed-loop control systems. The environment in which the motor encoder is used will determine the motor encoder technology that needs to be used. Two broad motor encoder technologies are: the output of the incremental motor encoder is used to control the speed of the motor shaft, and the output of the absolute motor encoder indicates the motor shaft Absolute motor encoders are most commonly used on servo motors in applications requiring position accuracy.

There are many types of motor encoder configurations, such as incremental or absolute, optical or magnetic, with shaft or hub/hollow shaft, etc. The type of motor encoder used depends on many factors, especially the type of motor, the application that requires closed-loop feedback, and the required installation configuration. When selecting components for a closed-loop control system, determine the motor encoder based on the motor type selected in the application. The most common motor types are:

AC motor encoder

AC induction motors are economical and robust, so they are a popular choice for general automated machine control systems. In applications where AC motors are used, motor encoders are used for more precise speed control and usually require stronger IP, shock and vibration parameters.

Servo motor encoder

Servo motor encoders (permanent magnet motor encoders) provide closed-loop feedback control systems for applications that require higher accuracy and precision and are not as powerful as AC induction motors. The motor encoder used on the servo motor can be modular, choose incremental or absolute, depending on the required resolution and accuracy level.

Stepper motor encoder

Stepper motors are economical, efficient and accurate. They are usually used in open-loop systems. In systems that use stepper motors that require speed control, an incremental motor encoder is often installed on the motor, which will make the stepper motor system a closed loop Feedback. Stepper motor encoders can also be used in certain applications to improve the control of stepper motors by providing accurate feedback of the motor shaft position relative to the step angle.

DC motor encoder

DC motor encoders are used for speed control feedback in DC motors. In this type of motor, an armature or rotor with a winding wire rotates in the magnetic field generated by the stator. The DC motor encoder provides a mechanism for measuring rotor speed and provides closed-loop feedback for the drive to achieve precise speed control.

Considerations for installing motor encoders

The next factor that affects the selection of motor encoders is the installation options. The most common options are: Shaft motor encoders use coupling methods to connect the motor encoder shaft to the motor shaft. The coupling provides mechanical and electrical isolation from the motor shaft, but will increase the cost through the coupling and the longer shaft length required to install the motor encoder. The hub/hollow shaft encoder is directly installed through a spring-loaded rope On the motor shaft. This method is easy to install and does not require shaft alignment, but appropriate measures must be taken to provide electrical isolation. Bearingless motor encoders are also called ring mounting. This mounting option includes a sensor assembly mounted on the surface of the motor in a ring form and a magnetic wheel mounted on the motor shaft.

in conclusion

An encoder is an electromechanical device that can provide electrical signals for speed and/or position control. The encoder converts mechanical motion into electrical signals. The control system uses the electrical signals to monitor specific parameters of the application, and when necessary Make adjustments to keep the machine running as required.