A method for starting a drive motor. The drive motor includes a motor stator with stator coils and a motor rotor, and a control electronics system and a power electronics system which supply power to the stator coils with a predefined coil voltage and a predefined constant start-up rotation frequency to generate a rotating field to drive the motor rotor. The method includes supplying power to at least one stator coil with a coil voltage corresponding to a start value, increasing the coil voltage in steps, monitoring an electric current flowing through the power electronics system, and, when a specific minimum voltage drop is detected, terminating the increasing of the coil voltage in steps, and performing a safety increase of the coil voltage by increasing a start-up voltage value by a predefined safety value to a first operating voltage value where the motor rotor is drivable in an unregulated mode.