If you hear the relay click but the motor doesn't spin, check the brushes on the DC motor itself. Finding Documentation
Features a current-limiting circuit to prevent motor burnout.
This board is a Pulse Width Modulation (PWM) DC motor speed controller. It converts AC input (typically 220V or 110V depending on the specific sub-model) into a variable DC output to drive the lathe’s permanent magnet motor. Regulates the RPM of the spindle motor.