What is a motor encoder? Motor encoder configuration types

A motor encoder is a rotary encoder mounted on a motor that 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. Applications that utilize specific parameters controlled by encoders or other sensors are 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: Incremental motor encoders whose output is used to control the speed of the motor shaft, and absolute motor encoders whose output indicates the motor shaft. Motion and position, absolute motor encoders are most commonly used on servo motors in applications that require positional accuracy.

Motor encoders are available in a wide variety of 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, notably the type of motor, the application requiring closed-loop feedback, and the desired mounting configuration. When selecting components for a closed-loop control system, determine the motor encoder based on the type of motor selected in the application. The most common types of motors are: AC Motor Encoders AC induction motors are economical and robust, making them a popular choice for general-purpose automated machine control systems. In applications using AC motors, motor encoders are used for more precise speed control and often need to have more robust IP, shock and vibration parameters.

  Servo motor encoder

Servo motor encoders (permanent magnet motor encoders) provide a closed-loop feedback control system for applications that require greater accuracy and precision and are not as powerful as AC induction motors. Motor encoders used on servo motors can be modular, choosing incremental or absolute, depending on the level of resolution and accuracy required.

Stepper Motor Encoder

Stepper motors are cost-effective and accurate, and are typically used in open-loop systems. In systems that use stepper motors that require speed control, incremental motor encoders are often installed on the motor, which will allow the stepper motor system to obtain closed loop feedback. Stepper motor encoders can also be used in certain applications to improve 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 where an armature or rotor with wound wires rotates within a magnetic field generated by the stator. DC motor encoders provide a mechanism to measure rotor speed and provide closed-loop feedback to the drive for precise speed control.

  Motor Encoder Mounting Considerations The next factor that affects the choice of a motor encoder is the mounting option, the most common option being: Shaft motor encoders use a coupling method to connect the motor encoder shaft to the motor shaft. Coupling provides mechanical and electrical isolation from the motor shaft, but adds cost through the coupling and the longer shaft length required to mount the motor encoder, the hub/hollow shaft encoder mounts directly via 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 known as ring mounts, this mounting option consists of a sensor assembly mounted in a ring form on the surface of the motor and a magnet wheel mounted on the motor shaft.

  Conclusion An encoder is an electromechanical device that provides electrical signals for speed and/or position control. The encoder converts mechanical motion into electrical signals that are used by the control system to monitor application-specific parameters and, where necessary, make adjustments from time to time to keep the machine operating as required.