Simple test to show if encoder is functional
An encoder is a type of feedback device that is often installed on a motor to monitor the motion (simple optical). A quadrature encoder indicates both motion and direction of the motor output shaft.
There are many different mounting options. Some are integral to the motor; others are coupled to the rear of the motor shaft. Some models have a wheel that fits on the motor shaft front or rear and the encoder stator mounts directly to a c-face on the motor.