One or more embodiments of the subject matter described herein relate to electric motors, such as traction motors of a vehicle. While certain embodiments are described in terms of traction motors of a locomotive or other rail vehicle, the subject matter described herein also may apply to other vehicles and/or other off-highway vehicles (OHV).
Known vehicles may include several electric motors, such as three-phase alternating current (AC) traction motors, that receive three-phase AC to power the motors. With respect to each motor, different phases of the current are passed to different conductive coils disposed in a stator of the motor. The current generates a magnetic field in the stator and causes a rotor of the motor to rotate within the stator. The rotor may be coupled with an axle or wheel of the vehicle by one or more gears or other couplings. Rotation of the rotor causes rotation of the axle and wheel to propel the vehicle.
Several mechanical components may be used to enable rotation of the rotor within the stator of the motor. For example, bearings may be disposed between the rotor and the stator to center the rotor in the stator and allow the rotor to rotate at relatively high speeds within the stator. Gears and/or other coupling components may be coupled with the rotor to translate rotation of the rotor to rotation of an axle or wheels. Over time, one or more of the bearings, gears, and/or other coupling components may begin to fail. For example, friction between a bearing and the rotor or stator, friction between gears, and/or friction between two or more other components of the motor may increase as the bearing, gear, or other component begins to mechanically fail. If the motor having the failing bearing, gear, or other component is not identified in time, the failing bearing, gear, or other component may seize or lock up and cause the motor to fail. Once the motor fails, the motor can no longer operate to propel the vehicle.
Some known systems and methods use additional sensors that are added to the motors of a vehicle to determine if the motor is tending toward failure, such as by a failing bearing, gear, or other component. However, the addition of these sensors can increase the cost and/or maintenance required for the vehicles. Moreover, some of these known sensors may be unable to accurately distinguish between a motor that is tending toward failing and external noise, such as uneven surfaces, tracks, and the like, that the vehicle is traveling over. For example, the uneven surfaces can cause the sensors to detect false positive identifications of a motor tending toward failure.
A need exists for a system and method for predicting impending mechanical failure of an electric motor that does not significantly add to the cost and/or maintenance of the vehicle and/or can accurately distinguish between failing motors and external noise of the system.