Abstract: A plurality of stationary markers (A, B, C, and D) are symmetrically placed at predetermined locations in the right of way of an electrically propelled traction vehicle on opposite sides of a transition point coinciding with a gap (14) between adjacent sections (13a, 13b) of a wayside conductor. Proximity sensing means (PSR, PSL) on the vehicle provide discrete output signals on a first line (43) upon passing the first and third markers (A and C) and on a second line (44) upon passing the second and fourth markers (B and D). Receiver logic means (42) includes means (108, 111-115, and 118-127), responsive to the output signals on the first and second lines, respectively, for producing a first control signal (on line 51) during the first-to-third marker interval and a second control signal (on line 50) during the second-to-third marker interval.

Abstract: An improved automatic control system for a train of transit vehicles which regulates the velocity of the train and its braking rate in accordance with a predetermined velocity/distance profile. The system includes apparatus for compensating for variations in wheel diameter and train length in such a manner as to assure that the center of the train regularly stops at a predetermined point with respect to a desired station stopping point. On board receivers are responsive to wayside signal devices for establishing the operating velocity of the vehicle and for initiating entry into the predetermined braking profile. Since vehicle control is effected by wayside signal devices, the distance between stopping points may be indefinite. The system includes apparatus which permits passing selected stopping points when desired.

Abstract: A self-propelled traction vehicle equipped with an a-c traction motor energized by the a-c output of a controlled current inverter is propelled by a process comprising the steps of providing a traction alternator on-board the vehicle, rotating the rotor of the alternator, exciting the field winding of the alternator, converting the output current of the armature windings of the alternator to a unidirectional current, and feeding the unidirectional current to d-c terminals of the controlled current inverter without appreciably smoothing the unidirectional current. A system for carrying out this process is also disclosed.

Abstract: A propulsion system for an electrically driven traction vehicle includes a chopper, a d-c traction motor, and means effective when the system is operating in a motoring mode for connecting the chopper in series with the armature and the field windings of the motor to a d-c electric power source that includes a filter capacitor. Cyclically operative means provides periodic gating signals for alternately turning on and turning off the chopper, and it can be smoothly changed from a constant frequency, variable pulse width mode to a variable frequency, constant (minimum) off time mode so as to vary the "duty factor" of the chopper over a wide range extending up to 100 percent on time. Brake set up means is operative in response to a motoring-to-braking command for reconnecting the chopper in parallel with the motor and the filter capacitor and for reversing the polarity of the connection of the series field winding relative to the armature.

Abstract: Apparatus for controlling the voltage on a commutating capacitor in a thyristor time ratio control power circuit whereby the energy stored in the capacitor may be continuously adjusted to a magnitude required for commutation so that the size of the commutating circuit can be significantly reduced. An inductive circuit is provided in a charging current path for the capacitor so that the capacitor can be charged above available source voltage by capacitive/inductive action. A controllable switch connected in parallel with the inductive circuit provides a short-circuit path for terminating charging of the capacitor. A logic circuit monitors capacitor voltage, source voltage and load current and closes the controllable switch when the capacitor voltage reaches a magnitude established by the logic circuit as sufficient to commutate the measured magnitude of load current.

Abstract: A combination of integrating and logic means in an electrical circuit responds to inputs from a variable analog control signal and from a constant frequency train of digital pulses. The magnitude of the control signal is variable between predetermined low and high extremes. The logic means periodically generates discrete output signals in synchronism with the digital pulses. When the control signal is lower than a predetermined intermediate magnitude, the integrating means is saturated and the logic means is able to produce the output signals at a constant frequency. When the control signal is between its intermediate and high extreme magnitude, the integrator is active and governs the operation of the logic means in such a manner that the average frequency of the output signals varies between its constant magnitude and zero as an inverse linear function of the control signal magnitude.

Abstract: A pulse shaping and amplifying circuit is formed by connecting a capacitor in series with the primary winding of a pulse transformer, connecting normally open switching means in parallel with the capacitor and primary winding, and connecting this parallel combination through a series inductor to a source of d-c control power, whereby the capacitor accumulates a charge from the control power source and then, during periods when the switching means is closed, discharges through the switching means and the primary winding. During its closed periods the switching means also conducts current from the control power source through the inductor, but when the switching means is opened the current in the inductor is transferred to the capacitor and the primary winding and thereby assists recharging of the capacitor.

Abstract: An a-c induction motor powered from an adjustable frequency and adjustable magnitude power source is provided with a feedback control system whose gain is varied as a function of the magnitude of flux developed in the motor in order to normalize system response throughout the motor operating range. The control system is a two-loop system in which one loop adjusts excitation frequency and the other loop adjusts excitation magnitude with the excitation frequency loop being responsive to a torque command signal and a torque feedback signal to generate an error signal which is utilized to adjust the excitation frequency of the power source. System gain is varied by modifying the error signal as a function of the magnitude of flux developed in the motor. Preferably this modification is performed by dividing the error signal by a signal representative of the magnitude of motor flux.

Abstract: A locomotive is provided with an enlarged cab having "split level" sections for accommodating the engineer and other members of the train crew. A first upper section includes seating space for the engineer adjacent to the console with good visibility to the front and back, the engineer's line of sight being above the crew members in a lower section of the cab, and on the opposite side of the cab there is an additional upper section that provides an operating station for the engineer's assistant. In the lower section of the cab seating space is provided for at least one crew member. A writing surface (for performing clerical work) adjacent to seating space for the train conductor, with external visibility along a line of sight parallel to the sides of the railroad cars being propelled by the locomotive, is provided either in the lower section or in the additional upper section of the cab.

Abstract: A shorted diode in an array of parallel diodes is detected by connecting between normally equipotential points in each pair of adjacent branch circuits of the array an inexpensive indicating device comprising signaling means for visually indicating that a malfunction has occurred if appreciable current flows in an associated resistor. The signaling means comprises heat sensitive material that changes appearance when its temperature is raised to a predetermined high degree by the heat generated in the resistor when current flows between the aforesaid connection points due to the potential difference that develops therebetween as a result of a diode failing shorted.

Abstract: A brushholder is adapted to be secured to the frame of a dynamoelectric machine by means of either insulated steel studs or resin-bonded fiber glass studs. The frame of the brushholder contains at least two holes which are spaced apart and in parallel. Each hole is adapted to receive one end of the steel stud as an interference fit or one end of the fiber glass stud as a clearance fit. An adhesive is used to bond the fiber glass stud in the hole. The wall surface defining the hole contains groove means which helps key the adhesive to the surface but does not detract significantly from the interference fit of the steel stud.

Abstract: For use with an adjustable speed a-c electric motor comprising a stator having effective direct and quadrature axes and a rotor spaced from the stator by a gap, said stator including windings adapted to be connected to a source of excitation of variable frequency and amplitude, a scheme is provided that comprises means for deriving a "torque angle" feedback signal representative of the phase angle between current and flux that interact in the motor to develop electromagnetic torque tending to move the rotor relative to the stator, in combination with means responsive to the torque angle feedback signal for controlling the source of excitation so as to control the frequency of stator excitation as a function of the torque angle feedback signal. In one aspect of the invention, means is provided for controlling the source of excitation so as to control the amplitude of stator excitation as a function of a variable command signal that is prevented from deviating below a predetermined limit.

Abstract: A reactor winding in the form of a high current, multi-turn, multi-layer insulated coil stack embracing an inner member of a magnetizable core assembly of a reactor is resiliently supported by the outer member of the core assembly by inserting a plurality of ripple spring sheets of non-magnetic material between the outer member and selected adjacent surfaces of the outer periphery of the windings. The inner core member is resiliently supported within the coil stack by an additional plurality of ripple spring sheets disposed between adjacent surfaces of the coil stack and inner core member. Ripple spring sheets are also positioned between adjacent surfaces of the inner and outer core members. The ripple spring sheets are preferably disposed between flat side sheets to provide uniform distribution of the spring forces.

Abstract: An electrical propulsion control system for self-propelled earthmoving traction vehicles of the type having integral earthmoving means and having a prime mover-driven electric generator supplying energy to traction motors, wherein the electrical output of the generator is regulated within predetermined maximum limits which are reduced in response to the application of a predetermined lifting force to the earthmoving means.

Abstract: A flux sensing coil is installed in each phase of the motor stator, and the resulting induced voltages represent the rate of change of air gap flux in that phase. The output voltage signals are integrated, rectified and summed to obtain an average motor flux signal which is in turn applied to vary the voltage to the motor in such a manner as to maintain a substantially constant motor flux level. In this way control errors due to motor parameter changes are eliminated and the flux margin normally required in motor design is reduced to achieve a more efficient utilization of the motor.

Abstract: A portable unit comprising a tiltable accelerometer is mounted on a vehicle which is allowed to coast on a plane and a reading is taken to provide an indication of vehicle rolling resistance without regard to terrain, slope, vehicle weight or speed. By proper precalibration of the accelerometer, it is possible to obtain the coefficient of friction directly from the accelerometer reading. Other values which may be directly obtained from the output of the accelerometer when it is properly recalibrated include accelerating rate and braking rate of a vehicle and grade of terrain.

Abstract: An electrical propulsion control system for self-propelled traction vehicles of the type having a thermal prime mover-driven electric generator supplying energy to traction motors, wherein the electrical output of the generator is regulated within predetermined maximum voltage, current, and power limits and is independently reduced, without reducing the voltage or current limit, in response to the prime mover decelerating to speeds at which it is subject to bogging.