Backstops prevent a run-back of the belt and load when the power supply is off. Since such a stop is installed directly at the rotor shaft and operates mechanically, no electrical connection is required: The bearing runs only in one direction. This principle achieves a higher holding torque than does an electromagnetic brake.
Note: Backstops are available only for asynchronous drum motors.
Rotational direction looking from the connector side: Available for clockwise (standard) or counterclockwise direction.