Speed control system for an AC locomotive
First Claim
1. A speed control system for an alternating current (AC) electric locomotive, the locomotive including a plurality of wheel-axle sets with each wheel-axle set being coupled to an independently controllable AC electric traction motor, each traction motor having a corresponding speed sensor and each speed sensor providing a pair of signals which are resolvable to determine the speed and direction of rotation of the associated motor rotor, the speed sensor signals being coupled to process control means which controls power to the motors, said system comprising:
- means for detecting the presence of each of the pair of signals from each speed sensor;
means responsive to detection of only one of the pair of signals from one of the speed sensors for setting motor speed in response to the detected one of the signals; and
means for using signals from another of the speed sensors for establishing motor rotational direction for the motor coupled to said one of the speed sensors.
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Accused Products
Abstract
A speed control system for an AC electric locomotive of the type having a plurality of wheel-axle sets with each wheel-axle set being coupled to an independently controllable AC electric traction motor and each motor having a corresponding speed sensor, each speed sensor providing a pair of signals which are resolvable to determine the speed and direction of rotation of the associated motor rotor, wherein the control system is arranged for maintaining torque control during failure of one of the signals from an associated speed sensor. The system detects the presence of each of the pair of signals from each speed sensor and responds to detection of only one of the pair of signals from one of the speed sensors for setting motor speed in response to the detected one of the signals. Direction is then determined by using signals from another of the speed sensors.
134 Citations
14 Claims
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1. A speed control system for an alternating current (AC) electric locomotive, the locomotive including a plurality of wheel-axle sets with each wheel-axle set being coupled to an independently controllable AC electric traction motor, each traction motor having a corresponding speed sensor and each speed sensor providing a pair of signals which are resolvable to determine the speed and direction of rotation of the associated motor rotor, the speed sensor signals being coupled to process control means which controls power to the motors, said system comprising:
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means for detecting the presence of each of the pair of signals from each speed sensor; means responsive to detection of only one of the pair of signals from one of the speed sensors for setting motor speed in response to the detected one of the signals; and means for using signals from another of the speed sensors for establishing motor rotational direction for the motor coupled to said one of the speed sensors. - View Dependent Claims (2, 3, 4, 5)
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6. A method for maintaining torque control of an alternating current electric motor coupled in driving relationship to wheels of a vehicle, the vehicle including other motors coupled for driving other wheels of the vehicle with each motor associated with it corresponding speed sensor, the method comprising the steps of:
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generating a pair of quadrature signals from each speed sensor wherein the phase relationship between the signals is indicative of a direction of motion of the vehicle; resolving the pair of signals to develop a third signal representative of speed of the vehicle for each speed sensor; comparing the pair of signals and the third signal to detect a failure of one of the pair of signals in any one of the speed sensors; and using, in response to detection of a failure of one of the pair of signals, another of the pair of signals to determine speed for the one of the speed sensors. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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Specification