Abstract: Flashover protection is provided for a locomotive propulsion system including a plurality of d-c traction motors each having a commutator subject to flashovers, a traction alternator having armature and field windings and a rotor driven by a prime mover, a controllable source of excitation current connected to the alternator field, and means including an electric power rectifier for connecting the alternator to the motor commutators. It comprises means for producing a fault signal whenever a flashover occurs in any motor, a solid-state controllable electric valve connected between the excitation current source and the alternator field and having alternative conducting and non-conducting states, and means for changing the valve from conducting to non-conducting states in response to a fault signal being produced, whereupon the magnitude of excitation current in the alternator field is rapidly reduced toward zero and the alternator's output current is correspondingly decreased whenever a flashover occurs.

Abstract: A modular electrical assembly is enclosed in an elastomeric weathershed housing, and has a plurality of electrical components aligned in a row and in electrical connection with one another via their axially-directed ends and under an axially-directed compressive force via a non-conductive filament winding. The filament winding defines a crisscross pattern with lateral openings for venting gas upon failure of one of the electrical components. The openings can be filled with fracturable epoxy or other insulating materials such as silicone grease.