A belt driven system, comprising: a belt sleeving on a master pulley of a motor and a slave pulley; a tensioner for tensioning the belt, including: a base; and a motor mounting bracket fixed on the base, wherein the motor is pivotally mounted on the motor mounting bracket via a pivot shaft and is lockable relative to the motor mounting bracket via at last one tension screw; wherein the pivot shaft is parallel to a central axis of the motor, the tension screw is screwable towards the motor, an end of the tension screw presses against a side wall of the motor, and the motor is configured to pivot away from the slave pulley of the belt driven system around the pivot shaft upon the tension screw being tensioned, wherein the motor mounting bracket is an L-shaped bracket including a first side plate and a second side plate, the base is fixed to the first side plate, an end surface of the motor is mounted on the second side plate and is locked to the second side plate, a side end of the second side plate includes a ledge extending towards an axial direction of the motor, and the ledge is provided with a screw hole for mounting the tension screw, wherein the motor and the motor mounting bracket are locked by one or more fastening bolts, the end surface of the motor is provided with one or more mounting holes, the second side plate is provided with one or more through-holes at one or more positions corresponding to the one or more mounting holes, and the one or more fastening bolts are screwed into the one or more mounting holes through the one or more through-holes, wherein the number of the one or more mounting holes is larger than 1, and the one or more mounting holes are provided along a circumference on the end surface of the motor. a belt sleeving on a master pulley of a motor and a slave pulley; a tensioner for tensioning the belt, including: a base; and a motor mounting bracket fixed on the base, wherein the motor is pivotally mounted on the motor mounting bracket via a pivot shaft and is lockable relative to the motor mounting bracket via at last one tension screw; wherein the pivot shaft is parallel to a central axis of the motor, the tension screw is screwable towards the motor, an end of the tension screw presses against a side wall of the motor, and the motor is configured to pivot away from the slave pulley of the belt driven system around the pivot shaft upon the tension screw being tensioned, wherein the motor mounting bracket is an L-shaped bracket including a first side plate and a second side plate, the base is fixed to the first side plate, an end surface of the motor is mounted on the second side plate and is locked to the second side plate, a side end of the second side plate includes a ledge extending towards an axial direction of the motor, and the ledge is provided with a screw hole for mounting the tension screw, wherein the motor and the motor mounting bracket are locked by one or more fastening bolts, the end surface of the motor is provided with one or more mounting holes, the second side plate is provided with one or more through-holes at one or more positions corresponding to the one or more mounting holes, and the one or more fastening bolts are screwed into the one or more mounting holes through the one or more through-holes, wherein the number of the one or more mounting holes is larger than 1, and the one or more mounting holes are provided along a circumference on the end surface of the motor. a base; and a motor mounting bracket fixed on the base, wherein the motor is pivotally mounted on the motor mounting bracket via a pivot shaft and is lockable relative to the motor mounting bracket via at last one tension screw; wherein the pivot shaft is parallel to a central axis of the motor, the tension screw is screwable towards the motor, an end of the tension screw presses against a side wall of the motor, and the motor is configured to pivot away from the slave pulley of the belt driven system around the pivot shaft upon the tension screw being tensioned, wherein the motor mounting bracket is an L-shaped bracket including a first side plate and a second side plate, the base is fixed to the first side plate, an end surface of the motor is mounted on the second side plate and is locked to the second side plate, a side end of the second side plate includes a ledge extending towards an axial direction of the motor, and the ledge is provided with a screw hole for mounting the tension screw, wherein the motor and the motor mounting bracket are locked by one or more fastening bolts, the end surface of the motor is provided with one or more mounting holes, the second side plate is provided with one or more through-holes at one or more positions corresponding to the one or more mounting holes, and the one or more fastening bolts are screwed into the one or more mounting holes through the one or more through-holes, wherein the number of the one or more mounting holes is larger than 1, and the one or more mounting holes are provided along a circumference on the end surface of the motor.