Abstract: An exemplary embodiment of the invention is a method for determining a reference speed approximating a ground speed of a vehicle having a plurality of axles. The method includes selecting a minimum vehicle speed based on one of the axles having a minimum speed. An axle having a lowest amount of creep is determined and designated as a speed axle. A derived speed from the speed axle is obtained and compensated by subtracting a creep value from the derived speed to obtain a corrected speed. Operating dynamics for the vehicle are determined and a reference speed is determined based on the minimum vehicle speed or the corrected speed in response to the operating dynamics.

Abstract: An exemplary embodiment of the invention is a method for determining a reference speed approximating a ground speed of a vehicle having a plurality of axles. The method includes selecting a minimum vehicle speed based on one of the axles having a minimum speed. An axle having a lowest amount of creep is determined and designated as a speed axle. A derived speed from the speed axle is obtained and compensated by subtracting a creep value from the derived speed to obtain a corrected speed. Operating dynamics for the vehicle are determined and a reference speed is determined based on the minimum vehicle speed or the corrected speed in response to the operating dynamics.

Abstract: A method and traction control system for an AC locomotive which separately controls the allowable creep level of each individual axle and optimizes traction performance by minimizing torsional vibration per axle. The traction control system includes a torque maximizer and a torsional vibration detector. The torque maximizer evaluates the change in traction system performance levels and actual creep level of individual axles and determines the desired torque maximizer state for maximizing traction performance of each individual axle. The torque maximizer utilizes digital filtering to minimize control cycle time. The torsional vibration detector digitally processes estimated torque feedback of each traction motor in order to detect an unacceptable level of torsional vibration. The outputs of the torque maximizer and the torsional vibration detector are provided to a creep modulator which processes these inputs in order to control the operating creep level of each locomotive axle.

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: 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 locomotive propulsion system includes wheelslip control with the following interrelated features: comparing the rotational speeds of the locomotive's separately driven wheels and detecting the highest and lowest; providing a reference speed value indicative of the rotational speed of a wheel that is not slipping; determining a desired maximum difference between the reference speed and a selected one of the detected speeds; deriving a speed error value by summing the reference speed, selected speed, and maximum difference; obtaining a wheelslip correction value which is a function of the speed error value; reducing the magnitude of voltage applied to the locomotive's traction motors in accordance with the correction value.

Abstract: The propulsion control system of a diesel-electric locomotive includes means responsive to the rotational speed and the gross horsepower of a locomotive engine for controlling the rate at which traction load is added to the engine, when more load is called for, so that the loading rate will increase (between predetermined minimum and maximum limits) as the product of speed and horsepower increases. The loading rate is also increased in response to the ratio of combustion air to diesel fuel increasing above a predetermined no-smoke threshold.