A method and apparatus for detecting and correcting the occurrence of flashover in a direct current electric motor. The polarity and magnitude of voltage on the field winding of the motor is continuously monitored. Detection of a sudden reversal of the polarity of the field voltage accompanied by a rapid increase in magnitude results in the generation of a flashover signal. The flashover signal is coupled to power controlling elements regulating power supplied to the motor and is effective to force removal of power from the motor. In a preferred embodiment the apparatus is disclosed in a two-motor system with two field windings serially connected such that the field voltage monitoring is accomplished on a differential basis.