Patent ID: 7035065
Filing Date: 2006-04-25
Classification: H02H

Abstract:
1. In a locomotive having a propulsion system with at least traction motors and alternators, a method of isolating an AC electrical ground fault in said propulsion system while said locomotive is operating in a braking or motoring condition, said method comprising: (a) operating said locomotive during a normal mission wherein said propulsion system will provide for braking and motoring of said locomotive; (b) monitoring alternating current within said propulsion system; (c) detecting an AC ground while said locomotive is braking or motoring; (d) determining which traction motor or alternator is causing said ground by selectively disabling a traction motor or alternator until the AC ground fault is found; (e) verifying said traction motor or alternator causing said ground is the correct traction motor or alternator by re-engaging said disabled traction motor or alternator; (f) if said AC ground is still detected, isolating said traction motor or said alternator causing said AC ground from said propulsion system; (g) if said AC ground is still detected, after a specific amount of time re-enabling said traction motor or alternator causing said AC ground to determine whether said AC ground remains; and (h) if said AC ground is still not detected, continuing operating said locomotive with all traction motors and alternators in use.