A device for controlling the output speed of a motor of a ring spinning machine, a ring twisting machine and the like in case of replacing travelers of such machines includes a speed setter for the motor and a potentiometer which is operatively connected with the speed setter to limit the output speed of the motor for allowing breaking in of replaced travelers. The potentiometer is further coupled with a speeding-up unit which is e.g. a stepper motor and which over a selected period of time increases the limited output speed to the normal operating level by automatically resetting the slider of the potentiometer from one end position to another end position.