Adjust the motor position.
The distance between the motor and the coupling pulley can be achieved by adjusting the position of the motor. The belt can be tightened by increasing the distance between the motor and the pulley of the coupling rod. However, the adjustable distance of motor position is limited, which is only applicable to the case of slight belt slack.
Replace belt
When the distance between the motor and the pulley of the coupling rod is maximum and the belt is loose, a new belt must be replaced.