Abstract: A wheel slip controller for a locomotive is disclosed that utilizes PID controllers to control the traction wheels during normal locomotive operation. The controller monitors several independent wheel slip indicators to provide rapid detection of excessive wheel slip. Upon detecting excessive traction wheel slip, motor control from the operative PID controller is suspended and a wheel slip compensator assumes command of the traction wheel drive motors. The wheel slip compensator then dynamically compensates the motors depending upon the amount of wheel slip that is detected. Once the wheel slip condition has been corrected, control of the traction motors is transferred back to the interrupted PID controller.

Abstract: The invention concerns a motor system of an electric type vehicle, comprising at least two asynchronous electric motors (M1, M2) supplied in parallel by a central electric supply. This central electric supply is controlled by a control device supplying thereto a first control signal (SCF) determining the value of the supply frequency (FAL) and a second control signal (SCA) determining the value of the supply amplitude (UAL) of the supply voltage. These first and second control signals are regulated essentially in dependence upon a signal (SMI) which is a measurement of the principal supply current (IAL), an instruction signal (SCS) and a signal (SFMX) representing the maximum value of the rotational frequency of the rotors (R2, R2) of said motors.

Abstract: An electronic sanding control system for enhancing the frictional adhesion existing between the track rail and the wheels of a railway vehicle by functionally controlling the energization and deenergization of a sanding magnet valve with a plurality of OR and AND logic gates and a sand control latch circuit.

Abstract: A driving force controller for an electric motor vehicle which suppresses changes in behavior of a vehicle when a right or left driving wheel experiences trouble and detects vehicle conditions to independently control the driving force of each wheel so as not to deviate from a predetermined range. The driving force controller computes a driving force for each wheel in accordance to a demand value for driving force and a detected vehicle traveling condition to drive each wheel independently by electric motors. Motor drivers control the motors so that each motor generates power corresponding to the value of driving force computed therefor. A driving demand detector detects the value of driving force demanded for the vehicle and a vehicle condition detector detects a traveling condition of the vehicle. Wheel driving condition detectors detect conditions at the wheels.

Abstract: A system for driving an electric automotive vehicle controls a slip frequency of a motor by feeding back to a signal control part a rotational speed detected by a motor speed sensor when the motor speed is normal. When the motor speed sensor is abnormal the system controls the slip frequency by feeding back to the signal control part the rotational speed estimated in accordance with an operating condition of the vehicle.

Abstract: An electric vehicle control system, according to the present invention, comprises at least two electric motors for independently driving left and right wheels of the vehicle, power supply unit for supplying power to the motors, unit for detecting command entered by a driver of the vehicle and driving operational amount provided for the vehicle, unit for detecting output torques of the two motors, unit for calculating a motor speed difference command signal for making the two output torques consistent with each other, unit for calculating a vehicle speed command signal for the vehicle on the basis of detected command and the driving operational amount, unit for calculating motor speed command signals for respective of the motors on the basis of calculated motor speed difference command signal and the vehicle speed command signal, unit for detecting actual speeds of the two motors, and control unit for voltage controlling supply power from the power supply unit to the motors so that the detected actual speeds o

Abstract: The invention relates to a method for filtering out disturbances in the form of short term wheel acceleration signals when the wheel exhibits an overall deceleration, so that a more accurate deceleration signal can be used for control of drive slippage.Wheel speed v is measured at intervals T.sub.A and speed changes for each interval are determined. When a change is negative or zero following a positive change in a previous interval, the wheel speed is stored as a maximum speed v.sub.max while v continues to be measured and a counter determines the period of time .DELTA.t between the occurrence of v.sub.max and the instantaneous value v. Beginning at a predetermined filtering time .DELTA.T after storing v.sub.max, a quotient .DELTA.v/.DELTA.t representing the filtered slope of the value v is determined and used as a control variable to regulate wheel slippage.

Abstract: A method of preventing wheel spin or wheel locking on an electric traction vehicle whose traction transmission includes servo controlling of one or more control parameters of the motor(s) of the traction transmission to an input reference value. The method is such that the control parameter(s) obtained at the output from the servo control are permanently limited by ideal values for the control parameter(s), which ideal values are such as to make it possible to obtain an input reference value for the speed of rotation of the motor(s) equal to the real travel speed of the vehicle, referred to as the reference speed, in such a manner as to stabilize the torque transmitted by the motor(s) in the event of wheel spin or wheel locking.

Abstract: A control apparatus for an electric rolling stock makes it possible to use a single associated train in a variety of transit services including an express transit service to an accommodation train service. The apparatus comprises an induction motor controlled by an inverter. For an express transit operation (over a long inter-station distance), the ratio of output voltage and the frequency of the inverter is decreased to thereby increase a command current in a variable voltage/variable frequency region. For the accommodation train operation (over short inter-station distance), a control pattern reverse to the above is adopted. The electric rolling stock can adapt itself to the running conditions. Besides, the problem of overheating of the induction motor can be solved successfuly.

Abstract: A drive system for a battery-powered vehicle is selectively operable in either a drive mode or an alternative battery-charging mode. In the drive mode, vector control circuitry is used to control instantaneous stator currents in an AC induction motor. The motor is preferably constructed having a pair of separately excitable three-phase windings spatially displaced by thirty electrical degrees. In the battery-charging mode, many of the same components are used to control battery charging current obtained as AC from a typical AC mains source.

Abstract: For a traction vehicle having two wheels driven by separate electric motors, a spin/stall condition is indicated if one of the wheels is rotating faster than a predetermined reference speed while the other wheel is not rotating, and a total stall condition is indicated if neither wheel is rotating and the magnitude of motor current exceeds a predetermined high level. Correction of any spin/stall condition is attempted by temporarily connecting a power resistor across the motor driving the spinning wheel, whereupon current (and hence torque) in the motor driving the stalled wheel will increase. Once a total stall is indicated, it is allowed to continue for a maximum period of time that varies inversely with the motor current magnitude, and if such condition is not earlier corrected motor damage is avoided by deenergizing both motors on the expiration of this period.

Abstract: A drive system with slip control for railway vehicles with two or more dc drive motors and with common control of the motor armature currents and a logic unit to which are input a measured signal which indicates the armature current intensity of the motor driving the axle having the best adhesion which is usually the trailing axle motor. The measured signal and an amplification signal are multiplied by each other and the product signal issued in a feedback loadsharing system to control the other motors such that the torque of the other motors increased to a maximum allowed level, the trailing axle then rolling very close to ground speed without slipping. This speed is used as a measure of the true speed, which in turn controls the system for loadsharing such that the vehicle can be controlled to maximum tractive effort without causing slipping axles.

Abstract: An electronic motor drive for vector control of an induction motor controls slip and operating frequency in response to changes in stator voltage. The drive includes a torque control loop, a flux control loop and a frequency control loop which includes slip control in response to a voltage difference. In the constant horsepower range, above base speed, slip is controlled in response to an error between a d-axis reference voltage that is sampled at base speed and a d-axis feedback voltage that is sensed when the motor is operating above base speeed. Flux-weakening is provided in response to an error between a q-axis reference voltage that is sensed when the motor is operating at base speed and a q-axis feedback voltage that is sensed when the motor is operating above speed.

Abstract: An AC-excited generator/motor apparatus comprising; an AC-excited generator/motor having an armature mounting thereon; an armature winding connected to an AC power system and a rotor mounting thereon; and an exciting winding excited by an AC current. An exciting device for supplying a controlled AC exciting current to the exciting winding comprises; a device for calculating a real slip frequency based on a difference between the phase of an armature voltage appearing on the armature winding and the rotational phase of the rotor; and a device for controlling the exciting current supplied to the exciting winding from the exciting means in response to a deviation of the real slip frequency from a predetermined allowable range of slip frequencies so as to restore the real slip frequency within the allowable range of slip frequencies.

Abstract: Differential wheel slip control is desirable in a locomotive having wheels driven by a plurality traction motors which receive power from an engine driven generator. Wheel slip control in known systems involves increased cost and complexity resulting from sensors required to determine an actual locomotive or individual traction motor speeds. In the subject invention a microprocessor under software control is used to detect and control differential wheel slip. A difference signal is generated in response to a difference between the highest and lowest individual traction motor currents. A first-order-lag of the actual locomotive speed is calculated and compared to the difference signal. If the compared signals differ by more than a preselected reference, a differential slip condition exists and the generator power is reduced by a preselected magnitude. Generator power is continually reduced until the slip condition no longer detected.

Abstract: This invention concerns a creepage control system for locomotives that optimizes adhesion while minimizing wasted energy, rail/wheel wear and shock loading on the drive train. The basis of the invention is to always maintain a small but positive value of the slope of the wheel-rail adhesion creep curve (or differential of adhesion versus creep) for all traction axles of the locomotive through microprocessor control. The value of the differential of adhesion versus creep is used to define an operating window for control and operation of motors continually in the optimum domain when high adhesion is demanded. When, due to a sudden increase in rail contamination, the value of the control function becomes negative, the microprocessor control reduces the generator excitation in stages until the function becomes positive and inside the operating window again. The microprocessor controls a rail cleaning system which is turned on or off depending on the cleanliness of the rail.

Abstract: This invention concerns a creepage control system for locomotives that optimizes adhesion while minimizing wasted energy, rail/wheel wear and shock loading on the drive train. The basis of the invention is to always maintain a small but positive value of the slope of the wheel-rail adhesion creep curve (or differential of adhesion versus creep) for all traction axles of the locomotive through microprocessor control. The value of the differential of adhesion versus creep is used to define an operating window for control and operation of motors continually in the optimum domain when high adhesion is demanded. When, due to a sudden increase in rail contamination, the value of the control function becomes negative, the microprocessor control reduces the generator excitation in stages until the function becomes positive and inside the operating window again. The microprocessor controls a rail cleaning system which is turned on or off depending on the cleanliness of the rail.

Abstract: Synchronous wheel slip control is desirable in a locomotive having wheels driven by at least one traction motor which receives power from an engine driven generator. Wheel slip control in known systems involves increased cost and complexity resulting from sensors required to determine an actual locomotive speed. In the subject invention a microprocessor under software control is used to detect and control synchronous wheel slip. Generator current and voltage are measured and used in an empirical relationship to calculate an actual locomotive speed. A first-order-lag of the actual locomotive speed is calculated and compared to the calculated locomotive speed. If the compared values differ by more than a preselected reference a synchronous slip condition exists and the generator power is reduced by a preselected magnitude. The generator power is incrementally reduced until the synchronous slip condition is no longer detected.

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: A DC voltage on an electric car stringing is supplied to a variable voltage and variable frequency PWM inverter so as to be converted into a three-phase alternating current which is supplied to a plurality of three-phase induction motors. The motors are connected to different wheels to drive an electric car. The inverter is controlled on the basis of an operating frequency command determined by adding or subtracting a slip frequency command to or from a motor speed and a voltage command proportional to the operating frequency command. On the other hand, a motor current command is set and compared with a maximum current value of currents of the plurality of motors, and the slip frequency command is corrected in accordance with a difference therebetween.

Abstract: The commencement of a developing period of slip is detected by the fact that a time-differential value v.sub.s of a creep velocity v.sub.s (a relative velocity between a peripheral velocity v.sub.m of a driving wheel and a vehicle velocity v.sub.t) exceeds a predetermined reference .delta..sub.1. The termination of the developing period is detected by the fact that a time-differential value v.sub.m of the peripheral velocity v.sub.m becomes equal to zero. During the developing period, a torque command Tp to a main motor controller is decreased by a re-adhesion control signal Tfa which is formed by the combination of a time-dependent component e.sub.1 and a slip-dependent component e.sub.2. After termination of the developing period, the torque command Tp is decreased with time at an appropriate time constant. According to the present invention, the arithmetic logic operation for control can be much simplified without any deterioration of a adhesion performance of an electric vehicle.

Abstract: A main circuit of an electric vehicle using an induction motor is constituted by an invertor for producing three phase AC power having a variable frequency and a variable voltage and a three-phase induction motor supplied with the AC power by the invertor. The rotational speed of the induction motor is detected and a slip frequency signal is added (in power running) or subtracted (in regenerating running) to or from the rotational speed to control the output frequency of the invertor. On the other hand, the output voltage of the invertor is controlled to be in proportion to the output frequency thereof. The output voltage of the invertor is limited in accordance with notch positions of a master controller of the electric vehicle so as to be provided with a voltage notch stopping characteristic of the conventional electric vehicle.

Abstract: Single-sided linear induction motors (SLIMs) suspended in proximity to the rail of a locomotive are energized to increase the effective adhesion between the locomotive drive wheels and the rail in response to the detection of an operating condition in which the tractive effort of the locomotive traction motors is limited by less than optimal adhesion. The SLIMs are energized in relation to the reserve power capability of the power source and the limit of tractive effort improvement. One method further employs sand dispensing units activated if the suboptimal operating condition is not alleviated by activation of the SLIMs. Another method uses the sand dispensing units first, and only activates the SLIMs if the suboptimal operating condition is not alleviated by activation of the sand dispensing mechanism.

Abstract: An automotive engine throttle control device has a function for effecting traction control for reducing the engine throttle opening upon detection of any slip of driving wheels and a function for effecting an automatic drive control for controlling the vehicle cruising speed in conformity with a command speed. The device has a first lever operatively connected to an accelerator and a second lever operatively connected to the throttle valve. A spring is disposed to resiliently act between the first and second levers. The second lever is actuated by an actuator which operates in response to throttle opening control instructions.

Abstract: A method of controlling the mode of driving an electric vehicle so that the electric vehicle is accelerated at a maximum acceleration and is decelerated at a maximum deceleration. The mode of variation of the running speed of the electric vehicle is estimated on the basis of the variation of the running speed of the electric vehicle calculated from the revolving speeds of the axles of the electric vehicle detected by revolving speed detectors associated with the axles, respectively. The axles are controlled for minute idle rotation or minute slip on the basis of the estimated mode of variation of the running speed of the electric vehicle to produce a maximum effective adhesion between the wheels attached to the axles and the rail so that the acceleration of the electric vehicle at a maximum acceleration and the deceleration of the same at a maximum deceleration are achieved.

Abstract: From the peripheral velocity v.sub.M of a driving wheel and vehicle velocity v, the changing rate .DELTA.v.sub.s /.DELTA.t of the relative velocity v.sub.s therebetween with respect to time is obtained. The changing rate .DELTA.f/.DELTA.t of the traction force f produced in the driving wheel at that time is obtained from a detected armature current of a motor driving the driving wheel. A driving torque produced by the motor is so controlled as to be decreased when polarities of the changing rate in the relative velocity and that in the traction force are different from each other.

Abstract: A device for detecting when a driven apparatus has frozen and/or its prime mover coupling mechanism is slipping. The rotational speed of a voltage generating alternator which is also driven by the prime mover is detected and a corresponding speed signal is compared to a reference speed signal. The reference speed signal corresponds to a speed slightly lower than the idling speed of the prime mover. When the detected speed signal is lower than the reference speed signal, slippage in the prime mover coupling mechanism is presumed and a slippage signal is provided. The slippage signal is used to control the coupling mechanism to disengage the apparatus from the prime mover to prevent damage from occurring.

Abstract: An electric vehicle monitoring system in which one induction motor has a rotational speed detector but another motor does not have such a detector. Separate current detectors monitor the current delivered to each of the motors. A calculations circuit uses the rotation of the one motor and a comparison of the two currents to monitor the performance of both motors.

Abstract: A protection circuit for monitoring and recognizing an undervoltage condition in the electrical system of a motor vehicle having an anti-skid brake control system in order to minimize and reduce any adverse effects on the braking action of the vehicle wheels. The protection circuit includes at least one comparator circuit to recognize if the voltage falls below a predetermined reference threshold voltage. When the supply voltage falls below the threshold voltage, the comparator circuit deactivates at least one of two diagonal switching circuits to remove automatic brakes on at least two wheels of a vehicle by the anti-skid brake control system.

Abstract: A traction drive system for a vehicle is disclosed which comprises a pair of series wound motors (32,34) which are connected in series with each other and which drive independent traction wheels (22,24), respectively, of the vehicle. The no-load torque of each traction wheel is correlated with the transient torque characteristic of the motors so that each motor produces a transient driving torque greater than the threshold-load torque of the wheels. Further, the no-load torque of each wheel is great enough so that the transient driving torque will not fall below the threshold-load torque during a predetermined time interval. This arrangement permits one traction wheel to move the vehicle at low speed while the other traction wheel spins on ice or otherwise fails to exhibit tractive effort.

Abstract: A plural motor changeover control system for using a plurality of motors (1a, 1b), the power outputs of which differ, by successively switching among the motors. A conversion table (32a, 32b) corresponding to a motor designated for operation from among the plurality of motors (1a, 1b) is selected, and an amplitude command is fetched from the selected conversion table, which command corresponds to a velocity error, which is a difference between an actual velocity of the designated motor and a commanded velocity. The amplitude command is applied to the servo control circuit to control the designated motor.

Abstract: An electric powered vehicle or the like includes a first mechanical drive system for a first side of the vehicle and a second mechanical drive system for a second side of the vehicle. A first DC motor and a second DC motor are respectively coupled to the first mechanical drive system and the second mechanical drive system. A source of DC power is on the vehicle. The first DC motor has a first field and a first armature and the second DC motor has a second field and a second armature. The first field, the first armature, the second field, and the second armature are connected in a series circuit with the source of power. A voltage sensing relay across the first armature can detect a high voltage across the first armature to sense a loss of traction of the first mechanical drive system. A switching circuit is employed to disable the first motor from the series circuit in response to the voltage sensing relay.

Abstract: A method and device for slip-limiting control on a rail vehicle wherein for controlling or limiting slip, it is necessary to determine the actual speed of the rail vehicle. The invention overcomes the problems in traction vehicles such as, for example, locomotives which only have driving wheels and no running wheels, especially if all driving wheels slip simultaneously. For the accurate determination of the vehicle speed, the traction motor current for the associated motor is reduced for a short period, of about 3 s, at the driving wheel which is rearmost in the direction of motion, by means of a slip-reduction signal which is supplied to a slip-limiting controller which also reduces the speed of this driving wheel so that this wheel no longer slips and its peripheral wheel speed is equal to the vehicle speed. During a presettable long-term period of about 25 s, all slip-limiting controllers of the rail vehicle are preset with a speed reference signal (v.sub.

Abstract: The invention disclosed is a control system for controlling a pair of separately excited motors arranged such that each motor of the pair drives a separate wheel on a common axle of an electrically powered vehicle. The control system continuously and individually adjusts the field excitation of the drive motors so that torque and speed of the separate wheels are apportioned to the wheels as a function of the steering angle of the vehicle.

Abstract: Apparatus for controlling wheel slip in a locomotive driven by d.c. motors which receive power from a diesel driven generator, has sensors which provide signals representing speeds of different driven wheels to a velocity unit. The velocity unit derives a differential signal representing the difference between the highest and the lowest wheel speeds. A sensor detects current or power in the generator output and the signal from this sensor is sampled periodically and the latest two sampled values are stored. The sampled values are compared to provide a creep reference signal. The differential signal and the creep reference signal are compared and the resulting difference signal is used to control generator output to maximize current during acceleration.

Abstract: A mobile track working machine arranged for intermittent advancement along the track comprises a drive, a brake for braking the driven wheels at respective working sites between the intermittent advancement of the machine, a speedometer generating a signal indicating the speed of advancement and a device generating a signal indicating the peripheral speed of the driven wheels. A fully electronically operated control arrangement for avoiding spinning of the driven wheels at the start of the advancement of the machine and locking of the wheels at braking includes a circuit having an input receiving the signals and an output connected to the drive and brake for constantly maintaining the nominal desired value of the drive and brake moments and for reducing the traction and brake forces in dependence on any drive or brake slippage.

Abstract: In the control of adhesion between a vehicle and a track, an adaptive control is provided for reapplying the tractive effort between the vehicle and the track in accordance with the known tractive effort level at which a loss of adhesion was sensed.

Abstract: The propulsion control apparatus for a vehicle including a plurality of motor driven wheel units detects a slip or slide operation of at least one wheel unit in accordance with a predetermined difference between sensed motor currents, and reduces the tractive effort of those wheel units until the sensed motor currents no longer have that difference.

Abstract: A microprocessor controlled wheel slip system for a train of railway cars receives wheel speed data, calibrates that data in accordance with a predetermined set of instructions, and indicates when a pair of wheels on an axle of a given car is slipping or spinning relative to the other wheels on the other cars of the train.

Abstract: A control system for an electric motor vehicle adapted to be driven by a group of induction motors, comprises a converter for producing an a.c. output to energize the group of induction motors, a frequency command circuit for producing a value representing a minimum number of rotations among those of at least two induction motors of the group added with a slip frequency in a power running mode of the vehicle on one hand and a value representing a maximum number of revolutions among those of at least two given induction motors of the group subtracted by the slip frequency in a regenerative braking mode, respectively, the values being utilized as frequency control commands, and a frequency control circuit for controlling the output for controlling the output frequency of the converter in dependence on the frequency control commands, thereby to improve the adhesion performance of the electric motor vehicle.

Abstract: A control apparatus is disclosed for an electric car having an induction motor supplied with polyphase AC power of variable frequency from a power converter so as to drive a driving wheel. This control apparatus comprises a detector for detecting the actual running speed of the electric car irrespective of whether the driving wheel causes adhesion or non-adhesion, a device for establishing a slip frequency of the induction motor, and a device for generating a frequency command based upon a signal of the actual running speed and the slip frequency, this frequency command being used to control the output frequency of the power converter.

Abstract: A railway vehicle has a plurality of motors for driving a plurality of wheels respectively, which motors are controlled to produce the same current to attain the same torque for each motor. These current values are detected respectively and received alternately in time division manner. A current value received is stored until the next current value for the same motor is received. The current value newly received is compared with the immediately previously stored current value for the same motor and the error therebetween is detected. When the current variation for the motor is larger than a predetermined value, the slipping of the wheel driven by that motor is detected. Also a received current value is compared with the current values for the other motors, and if the error is larger than a predetermined value, the slipping of the wheel driven by the motor associated with the received current value is detected.

Abstract: A method and apparatus are described for regulating the armature currents of a plurality of electric motors connected to share the same load, but having separate power sources. The described method and apparatus thereby operate to enhance the load-sharing characteristics of these motors. Each of the motors is provided with armature currents by a separate generator set so that each motor is connected in an individual Ward-Leonard type system. The fields of each of the motors are excited separately from the aforementioned separate power sources. The armature currents for each of the motors are individually sensed, and values corresponding to the armature current values are derived. The latter analog values are compared with an average value for all of the armature currents.

Abstract: An electronic differential speed control circuit for driving the inboard and outboard A.C. wheel motors at different relative speeds depending upon the steering angle during a turn. An electrical circuit for sensing the torque of the tractor's wheel motors to maintain a constant implement draft. A hollow tubular axle pivots around the tractor's longitudinal material-transferring tunnel to conserve space and permit mounting of the wheel motors within the axle. The tunnel has two material-transferring compartments or passageways, and has vertically movable extensions on either end to facilitate coupling to accessories. An electrical power outlet is provided for energizing non-motor driven accessories.

Abstract: An analog signal representation of the ground speed of a prime mover driven vehicle is modified by the vehicle drive train ratio factor to produce an analog signal representation of the theoretical speed of rotation of the prime mover rotating element based upon vehicle ground speed and another analog signal representation of the actual speed of rotation of the prime mover rotating element based upon selected prime mover operating parameters is produced. A variable gain amplifier circuit converts the theoretical speed of rotation analog signal representation into a system output calibrated analog signal representation of the actual speed of rotation of the prime mover rotating element based upon vehicle ground speed by incrementally adjusting the potential level of the theoretical speed of rotation analog signal representation in a direction toward that of the prime mover operating parameter based actual speed of rotation signal representation.

Abstract: A method for determining the spinning or slipping of the wheels in propulsion vehicles without dead axles, particularly railroad vehicles in which: the highest and the lowest wheel velocity of the measured wheel velocities of all axles is determined; the highest wheel velocity is selected in the presence of a braking command, and otherwise, the lowest wheel velocity is selected; a simulated car velocity is determined from the selected wheel velocity taking accelerating or decelerating influence variables into consideration; and the simulated car velocity is compared with the measured wheel velocities and the differences that result are converted into signals for influencing the drive or the braking device of the respective axle.

Abstract: A vehicle includes drive wheels and a motor connected thereto with torque controlling apparatus and a slip indicating device. Excessive slip indications per unit time are monitored and cause reduction in the torque applied by the motor until the slipping is overcome at which time torque is gradually increased.

Abstract: A wheel slip correction system of the type in which boost current is supplied to the field winding of a d-c electric traction motor driving a slipping wheel from an a-c source in order to correct the slip is provided with a control system which automatically inhibits the application of boost current if control power fails. A current transformer connected to provide power to the field winding from the a-c source has a secondary winding normally short-circuited by inversely paralleled thyristors thus inhibiting power transfer to the field winding. The thyristors are maintained short-circuited by a current amplifier connected across the transformer secondary and adapted to normally supply current to the gate terminals of the thyristors. The current amplifier is inhibited by receipt of a wheel-slip signal so that the thyristors remain non-conductive and boost current is supplied to the motor field.

Abstract: The following specification described a method or system of correcting locomotive wheel slip in which each driven wheel provides a wheel velocity signal proportional to its angular velocity. This signal is compared in a wheel slip detection circuit for each wheel with a train speed signal to derive a signal corresponding to the difference in the event of wheel slip. This difference signal is differentiated to provide a signal corresponding to the acceleration and multiplied by a signal corresponding to the slipping wheel speed to provide a correction signal corresponding to the power lost in the slipping wheel.The wheel velocity signals are compared in a "less than" and a "greater than" circuit respectively to derive the train speed signal and the slipping wheel signal.

Abstract: This specification discloses a rail car for carrying hot coke from a coke oven to a quenching station in combination with a control system for automatically controlling the acceleration, deceleration, stopping and starting of the rail car to achieve optimum cycle times having regard to track conditions. The rail car includes a chassis supporting a load container and a plurality of wheeled bogies supporting the chassis and container, at least the forward bogie being directly driven by two electric traction motors and being located at the position of maximum weight of the rail car. The motors provide both acceleration and braking torques for the rail car and are controlled by the control system. The control system includes a slip detection circuit connected to a speed regulator for modifying the regulation applied by the speed regulator to remove wheel slip. The speed regulator is controlled via a ramp generator which dictates the acceleration and deceleration profiles for the motors.