The invention provides a control unit for at least one electric motor, wherein the control unit performs open-loop or closed-loop control of the motor speed of the electric motor in such a way that in the case of control values in specific ranges which are typical of a fault when the setpoint value is being predefined, such a fault being, for example, a line break, a voltage failure or a short circuit, the control unit drives the motor with a predefined setpoint value which differs from the current control value.