Patent ID: 6781808
Filing Date: 2004-08-24
Classification: B60L

Abstract:
A method for detecting, during normal operation of a locomotive and without interrupting said locomotive operation, faults indicative of an electrical short condition in at least one power device of a plurality of power devices of a propulsion system of said locomotive, said plurality of power devices connected in parallel circuit to an external direct current power source operationally coupled for electrically powering said propulsion system as the locomotive travels along a rail track proximate said external power source, the method comprising:upon said power source being electrically connected to the locomotive propulsion system when the locomotive is on said rail track proximate said external power source, measuring an initial voltage across a power line filter in a circuit with the power devices; measuring voltage developed across said line filter upon waiting a predefined transient time interval; and determining the presence of an electrical short condition in at least one of the power devices based on whether the magnitude of the voltage developed across the line filter rises to about power line voltage within said predefined transient time interval, wherein said time interval is sufficiently short to avoid interrupting said locomotive operation, and to avoid damage to the propulsion system in the event said electrical short condition is actually present, and further wherein said time interval is sufficiently long relative to the time constant of the filter to enable said voltage to rise to about line voltage when a short condition exists.