Abstract: The present invention provides driver circuitry for commutated inductive loads, and in particular, inductive loads employed in multi-pole DC brushless motors. The preferred embodiment of the present invention typically implements three pull-up and three pull-down drivers for motor control. The pull-down driver circuit described in the present invention can be configured to be adjusted by an external component of the integrated circuit implementation in order for controlling turn-off transients. Voltage transients due to changes in load current in the control loop of the pull-down driver circuit can be minimized or deterministically controlled by controlling the rate of change of the input voltage. For the case of when the load current is to be completely switched from one inductor to another inductor, an additional unity gain buffer coupled to the input voltage is inserted into the control loop of the pull-down driver circuit for reducing the voltage transients that can result.

Abstract: A universal electric motor having an arbor mounted on a rotating armature with a run winding for generating a magnetic field having a polarity relative to the armature and for rotating the arbor, a first switch for connecting the run winding to a power source, and a brake winding for generating a counter magnetic field opposed with respect to the armature winding to that generated by the run winding.

Abstract: A controller for a vehicle fuel pump electric motor is connected to one or more vehicle sensors for sensing fuel flow demand and pulse width modulating the motor to control the speed. A fuel demand sensor and a triangle generator are connected to a summing controller for generating a pulse width modulated control signal to a driver. The driver has a pair of outputs for generating a pair of complementary pulse width modulated switch signals to a pair of switches whereby the switches are switched on and off alternately. One of the switches is connected in series between a power supply and the motor armature and the other switch is connected across the armature. A crash sensor, such as an inertia switch, is connected to the summing controller for terminating pulse width modulation in the event of a crash. The switch connected across the armature can be turned on to short circuit the armature and quickly stop the motor in the event of a crash.

Abstract: A control system for an electric machine powered from a DC source, wherein controlled motoring and controlled braking are achieved with a single current regulator control, even when the DC source cannot accept charging current and/or the induced motor voltage exceeds the DC bus voltage. The motor control circuit comprises a DC source connected to a DC bus, a current control circuit for modulating switching devices connected across the DC bus, an energy exchange capacitor connected across the DC bus, a load resistor, a switching circuit effective when activated to interrupt a connection between the DC source and the DC bus and to connect the load resistor across the DC bus in parallel with the capacitor, and a logic circuit for activating the switching circuit during motor braking under conditions for which the modulation of the switching devices is ineffective to control the braking current.

Abstract: A transmission control system in an electric vehicle in which a battery is used as en energy source for a motor and is charged with an electric power generated through the motor by regenerative braking of driving wheels which are connected to the motor through a transmission. In the transmission control system, a regenerative energy capable of being generated at a current transmission ratio, a regenerative energy capable of being generated when such transmission ratio is increased, and a regenerative energy capable of being generated when such transmission ratio is decreased, are calculated and compared with one another, thereby shift-changing the transmission into a shift position which permits the largest regenerative energy to be provided. This ensures that the efficiency of recovery of the energy can be increased to the maximum to effectively charge the battery.

Abstract: An improved electrical circuit configuration for a chopper circuit is disclosed which is particularly adapted for use with an inductive load such as a braking resistor of the type used in many rapid transit vehicles. Instead of connecting a di/dt reactor directly in series with the electronic switch of the chopper circuit, a di/dt reactor is connected in series with the freewheeling diode. Using this configuration, the di/dt reactor does not have to continuously handle the average current through the electronic switch during the entire chopping operation. Hence, a much smaller, lighter, and less expensive di/dt reactor can be utilized.

Abstract: A method for determining operability of a dynamic braking system in an electrically propelled traction vehicle by cycling selected switching devices while the vehicle is at rest and measuring voltages and currents generated in response to operation of the switching devices. In one form, the dynamic braking system is operated to be connected to a power conversion system of the vehicle and the voltage developed at the braking system compared to the voltage coupled to the vehicle. Using prior knowledge of system resistances, calculated ideal values of voltage are compared to measured values to confirm proper system operation. Malfunctions of particular components are logically determined by ratios of measured to ideal values and by operation of selected ones of the switching devices.

Abstract: A control for an automatic washing machine with a reversing permanent split capacitor (PSC) drive motor. Separate ferrite core sensors surround each of two PSC motor windings. A sense winding is threaded through both sensors. A brief output voltage is generated whenever the alternating current in either PSC motor winding passes through a zero-crossing and when the sense winding is wound with proper mutual polarity, an output voltage is generated in response to zero-crossings of a brief, residual alternating current which flows in both PSC motor windings and the capacitor when the rotating PSC motor is cycled OFF.

Abstract: To provide sufficient magnetization to the field of a series motor when the series motor is to be operated in dynamic braking mode, with a dissipating resistor or short circuit element (4) connected across the armature (5), a circuit connection is established between one of the main terminals of the motor through the series field to supply a minimum magnetization current, at least when the motor operates under dynamic braking conditions, typically a few to up to 15% of no-load current of the motor. This is sufficient magnetization so that, even in larger motors where remanent magnetism of the field structure is insufficient, reliable dynamic braking can be ensured. A switch (S; S.sub.1, S.sub.2) selectively connects the motor armature for motor drive or running operation and dynamic braking operation.

Abstract: In a 2 pole universal motor for a circular saw a secondary winding provides dynamic braking. Both run and brake windings are split electrically with respect to the armature. All windings are double-ended and wiring and winding is arranged so that all windings may be terminated directly to fixed termination points, four at each end of the stator, providing for axially oriented plug-in connection of brushes at the commutator end and switch and line at the fan end. There are no jumpers within the stator.

Abstract: An apparatus for controlling dynamic braking in a vehicle having at least one drive motor of the type having an armature and a field. The motor is adapted to function as an alternator during dynamic braking for dissipating power through a resistor grid. The vehicle includes a field current controller for regulating the level of dynamic braking by controlling the current level through the motor field. A brake level selector is provided for producing a desired braking level signal. A field current sensor senses the current level in the motor field and produces an actual field current signal. A grid current sensor senses the level of current flowing through the resistor grid and produces an actual grid current signal. A controller receives the desired brake level signal, the actual field current signal, and the actual grid current signal. The controller produces a first desired field current signal and a desired grid current signal in response to the desired brake level signal.

Abstract: A control apparatus for a motor including m number of stator windings and a relay having m-1 contacts, thereby allowing the control apparatus to be simplified in its structure so that the control apparatus can be constructed at a low cost.

Abstract: A conveyance (360) is provided with: dynamic braking of electric propulsion motors (26a and 26b) that is achieved by shorting a motor winding (150a) during a portion (233a) of an interval (217a) between pulses (207a) of a pulse-width modulated driving voltage (209a); automatic limiting (233) of the rate of change in power supplied to left (26a or 232a) and right (26b) propulsion motors, whether electrically or hydraulically propelled; power-off braking that is achieved by shorting a motor winding (150a) when power pulses are not being supplied; extended life of relays (144aand 148a) that is achieved by preventing current flow to the motors during opening and closing of the relay contacts (154a and 156a); and a solid-state switching device (168a and 170a) that is controlled by a signal in a single conductor (200a) and that provides an effective delay (219a and 221a) in switching between two circuits (152a and 160a).

Abstract: The electromagnetic braking arrangement comprises an exciting winding which is supplied from a generator winding which on the one hand excites the generator winding and on the other hand induces a braking torque in a short-circuited winding moved with the generator winding. The excitation current of the exciting winding is controlled by a transistor of a current-regulating circuit which holds the excitation current and thus the braking torque at a level adjustable at a reference voltage source. The iron circuit of the exciting winding has residual magnetic properties which ensure an initial self-excitation. The components of the control circuit are supplied with operating voltage from the generator winding via a rectifier circuit. A resistor, which is directly connected to the rectifier circuit, controls the transistor in the conductive state even when the operating voltage is insufficient for proper operation of the control circuit.

Abstract: An automatic braking and speed control for a device driven by an electric motor. A controller provides a pulsed output voltage having a pulse width dependent upon the load seen by the motor (16). When the drive pulses are present two diodes (52,54) and a transistor (66) serve to maintain a power transistor (56) in the off condition. When the controller is not providing drive pulses and the motor (16) is being turned by the momentum of the mechanical device or by some outside force, such as gravity, the motor (16) functions as a generator and turns on two transistors (56,67) so that two resistors (51a,51b) apply a load to the generator (16). This provides a braking action between the output pulses so that the net speed of the motor (16) and its associated mechanical device is more dependent upon the output pulses provided by the controller.

Abstract: Arrangement for winding of an electric cable which arrangement comprises a rotatable drum from which the cable is arranged to be wound off manually, and an electric motor (M) arranged to be connected to a first circuit for driving the drum in the winding direction and arranged to be rotated by the drum during unwinding of the cable. A second circuit (M,1,3,4) comprises besides the motor (M) also a contact means (1) arranged to be closed when the motor (M) is inoperative. During unwinding of the cable from the drum the motor generates a braking moment which increases with the speed of rotation of the motor.The second circuit preferably comprises a voltage dependent switch (3), preferably a Zener-diode, which is arranged to be closed when the voltage generated by the motor (M) during the unwinding exceeds a value corresponding to a predetermined speed of rotation of the drum and, as a consequence, of the motor.

Abstract: A conveyance (10) is provided with: automatic limiting (223) of the rate of change in power supplied to left (26a or 232a) and right propulsion motors, whether electrically or hydraulically propelled; dynamic braking of electric propulsion motors (26a and 26b) that is achieved by shorting a motor winding (150a) during a portion (233a) of an interval (217a) between power pulses (207a) of a pulse-width-modulated driving voltage (209a); power-off braking that is achieved by shorting a motor winding (150a) when no power pulses are being supplied; extended life of relays (144a & 148a) that is achieved by preventing current flow to the motors during opening and closing of the relay contacts (154a and 156a); and a solid-state switching device (168a and 170a) that is controlled by a signal in a single conductor (200a) and that provides an effective delay (219a and 221a) in switching between two circuits (152a and 160a).

Abstract: A method of and an arrangement for controlling the operation of a reversible D.C. electric motor including a winding having two ends each of which is connected to both the positive and negative terminals of an electric current source through respective control switches that can be selectively closed and opened in response to command signals to apply voltage differentials across the winding with attendant electric current flow through the winding in one or the opposite direction for operating the electric motor in one or the other of its senses of rotation with intervening rotation sense reversals utilize the original command signals for determining when the sense of rotation reversal would result in an excessive electric current flow through the winding.

Abstract: A stepless speed change electric chain block includes a DC motor for driving a load sheave. The chain block comprises a phase control circuit having a variable resistor, a capacitor, a two-way trigger diode, and a triode AC switch for receiving alternating current from alternating power source to control it in phase, a full-wave-rectifier for receiving alternating current controlled in phase in the phase control circuit to convert it into direct current which is supplied into the DC motor, and mechanical brake means provided in a transmission between the DC motor and the load sheave for braking rotation of the load sheave in a winding-off direction. With this arrangement, as the speed setting for winding operation is effected only by the phase control circuit, so that the constitution of the block is simplified and inexpensive in comparison with the prior art. All the supplied power is effectively utilized for operating the chain block.

Abstract: In a tape drive system, a dynamic brake control circuit provides dynamic braking for slowing and stopping an associated tape reel and motor system in the event of a power failure. Upon sensing a power failure, the electrical energy stored in a capacitor supplies electrical energy to enable the control circuit, which in turn supplies a controlled conductive path for the flow of a dynamic braking current due to the back electromotive force signal generated by the motor, to effect the controlled dynamic braking of the drive motor to a stop.

Abstract: A movable storage unit control system is provided with: a leading edge safety tape switch for contacting it to bring a driven unit to a stop; a processor for generating move and stop command signals; a plurality of circuits through which test signals are transmitted under control of the processor and which are returned to the processor coincidentally with their transmission through a current sensor if the circuit tests good; a procedure for having the processor address a test signal to a nonexistent circuit to determine if the current sensor has failed and is allowing return of signals when it should not; circuits for setting minimum and maximum speed of the motors that drive the storage units; a circuit for setting the intensity of dynamic braking of the drive motors; and, a watchdog circuit that shuts down the processor upon occurrence of intense temporary electrical noise or software execution errors and is involved in causing the processor to shut down and block all commands to the system if the processor

Abstract: A system is disclosed for recovering and storing the energy generated by an electrical motor during deceleration so as to be available for use when the motor is subsequently accelerated. The system utilizes a capacitor for storing the energy produced by voltage regeneration of the motor when decelerating. A two-quadrant regulator, connected between a three-phase rectifier and a four-quadrant SCR regulator, controls the charging and discharging of the capacitor so that the energy stored therein is proportional to the energy required to accelerate the motor and load to the maximum rotational velocity required.

Abstract: A computed tomography scanner having a brake which is automatically engaged in the event dynamic motor braking fails to stop scanner motion. Within a predetermined range of motion two brake mechanisms are employed. One has a brake shoe to contact a braking surface and stop rotation of the scanner in one direction and a second has a second brake shoe which stops rotation in an opposite direction. The brake shoes are engaged and retracted by a cam surface which as the scanner rotates, moves into contact with one of two bearings connected to associated ones of the brake shoes.

Abstract: Apparatus for controlling d-c shunt motors of electric cars utilizes first chopper circuits connected in series with the armatures of the d-c motors for controlling armature currents upon receipt of a first set of control signals and second chopper circuits connected in series with the field windings of the d-c shunt motors for controlling the field currents responsive to a second set of control signals, reactors having first and second coils, the first coils being connected in series with the armatures and the second coils being connected in series with the field windings, with the first and second coils magnetically coupled together to maintain a relationship that the field currents decrease with a decrease in the armature currents.

Abstract: A solid-state electronic control system for an electric motor which drives a pipe bending machine. A machine operator's hand switch acts through a logic system to cause the motor to run in either direction, and negates control conflicts.The logic system controls an SCR bridge system to select the direction of D.C. energization of the motor for forward or reverse drive. This bridge system is supplied from A.C. mains through a bridge rectifier comprising three diodes and one SCR. When motor drive is called for, this SCR is made conducting to provide full-wave rectification. When motor drive is terminated, this SCR is turned off so that the rectifier becomes half-wave, which facilitates turn-off of the motor reversing SCR's.A dynamic brake for the motor is turned on by a triac when motor energization is shut off.

Abstract: In an electrical tool having a clutch for adjusting rotational torque of the driven shaft, a limit switch of double-throw type is used for detecting the state of the clutch, and a capacitor is arranged to be charged via the limit switch. In one embodiment of the instant invention, the capacitor is normally discharged and is charged when the clutch assumes a disengaged state, thereby producing a trigger pulse used for making a short circuit for the motor only when the capacitor is not fully charged. In another embodiment, the capacitor is normally charged, and is discharged when the clutch assumes a disengaged state, thereby producing a trigger pulse used for making a short circuit for the motor. With this arrangement a switching circuit provided for making the short circuit for the motor is effectively prevented from making the short circuit when a power switch is turned on irrespective of the state of the clutch.

Abstract: A control circuit which permits a direct current motor to operate during traction or during braking in such a manner that energy can be either dissipated or recovered; and, in particular, the invention embodies gradual, continuous, and reversible shifting from one form of braking action to another.

Abstract: A control system (28) is provided for controlling the supply of power to a motor (12) having an armature (34) and a plugging diode (38) connected across the armature (34), including a circuit (14) for producing direction command signals, a circuit (98) for generating digital motor power command signals, a circuit (16) for sensing a plugging condition and generating a plug signal, a microprocessor (46) for generating one of a plurality of pulse trains during typical plugging conditions and for automatically overriding the generation of the one pulse train and generating other of the plurality of pulse trains during special plugging conditions. By automatically providing the override feature during the special plugging conditions, the disadvantage of manual override in prior control systems is obviated.

Abstract: An elevator speed control system permitting rotation of the motor with short-circuited rotor at full speed, wherein the thyristors controlling said motor permit the motor to rotate at full speed and when the elevator is running in the lighter direction, operation of the motor as generator at an over-synchronous speed. The system comprises a control unit assembled of components known in themselves in the art by which the instruction value is increased considerably past the actual value, whereby the motor with short-circuited rotor is left to rotate at full speed, and that on commencing retardation the instruction value is dropped directly to be consistent with the actual value.

Abstract: A three state driver for an inductive load, e.g., a stator winding of a variable reluctance motor, allows the use of charge, idle, and discharge states in which a positive voltage, a short, and a reverse voltage are connected across the inductive load, respectively. An H-bridge comprising two electronic switches and two diodes is used to switch the inductive load voltages as commanded by a comparator circuit which compares the load current to a desired load current.

Abstract: A motor driving circuit in which the opposite ends of the motor driving coils of a video tape recorder (VTR) capstan motor are shorted by a group of switching elements when a control input voltage generated from a rotation detection/oscillator is in a predetermined range.

Abstract: A power fail circuit provides protection for tape such as used in the tape transport apparatus of a video recorder in the event of a failure of the external power supply. The tape transport apparatus includes as a feature the provision of an electrical error signal used to govern drive motors to maintain substantially constant tape tension when the system is operating normally. After power failure occurs, the power fail circuit continues to respond to the error signal by coupling current from the drive motors to provide dynamic braking. Further, current taken from the drive motors selectively is coupled to an energy storage device operatively associated with the system power supply, to provide augmenting energy from the kinetic energy of the motors for continued control of the power fail circuit as the drive motors are caused to decelerate under control to stop.

Abstract: In an electric drive for a DC shunt propulsion motor which is supplied from a battery, the armature winding is connected to the battery, and the field winding is connected to the battery via an electronic DC control element. The electronic DC control element is associated with the field winding and also serves as a control element for charging the battery. The DC control element is further equipped with a voltage control device in addition to a current control device. A multiposition switch is arranged so that when the switch is in one position the field winding is connected via the electronic DC control element to the battery, and when the switch is in another position, the electronic DC control element is shunted across the battery.

Abstract: A rapidly-spinning motor-driven disc is quickly brought to a halt by utilizing the motor in a controlled current dynamic feedback mode. An electrical signal is provided to cut off the motor braking current when the rotating motor shaft reaches substantially zero velocity, thereby avoiding any residual rotation of the disc. As the disc slows at a constant deceleration rate, the apparatus measures the relative time durations of two consecutive pulses which represent equal displacement arcs on the disc. From these data the time at which zero velocity will be achieved is computed, and the motor current cutoff signal is generated at the proper instant.

Abstract: A braking control circuit for an alternating current motor is disclosed as having a winding and adapted to be coupled to an energizing control circuit for connecting a source of AC voltage to and for disconnecting the source of AC voltage from the winding. The braking control circuit comprises a selectively controlled rectifier operative in a first conductive mode for applying rectified current to the winding to brake the motor and in a second non-conductive mode, and a switching circuit coupled to the rectifier and responsive to the disconnecting of the source of AC voltage from the winding for switching the rectifier between its first and second modes at a first switching rate to brake the motor rotation at a corresponding first braking rate, and thereafter for switching the rectifier between its first and second modes at a second switching rate different from the first switching rate to brake the motor at a corresponding second braking rate.

Abstract: Emergency braking device for a brushless motor comprising damping means connected through a switch to the windings of the brushless motor in case of emergency to dissipate the energy stored in the inductance of the windings of the brushless motor. The impedance characteristics of the damper means are optimized by selecting a capacitance which has a predetermined relationship to the inductance of the motor winding.

Abstract: An electrical braking circuit provides smooth transitioning between regenerative and plug braking of a DC electric motor by use of a low ohmic value resistance path to maintain motor torque during transitioning. During initiation of electrical braking, a similar low ohmic resistance path momentarily connects the motor to a power source in order to establish proper magnetic flux in the motor to enable regenerative braking. Both resistance paths are disabled during motoring and braking modes of operation in order to minimize power loss in the resistance paths.

Abstract: A DC motor control apparatus is disclosed comprising a first pair of switching elements coupled respectively with oppositely poled ends of the DC motor. A first actuating means is provided for actuating one of a first pair of switching elements in response to an input signal of a first predetermined logic content. The other of the first pair of switching elements is provided to respond to an input signal of a second predetermined logic content. Also provided, are means for applying a driving potential to the oppositely poled end of a motor simultaneously with the actuation of each of the first pair of switching elements, thereby establishing a current path for forward direction and reverse direction operation of said DC motor, respectively. A second pair of switching elements are respectively connected to oppositely poled ends of the DC motor.

Abstract: A system for automatic control of dynamic braking of an independent transport facility comprises an exciting-current regulator of traction motors provided with rotational-speed transducers whose outputs are connected to the input of a traction-motor reactive e.m.f. limiter, and a voltage transducer whose output is coupled to the first input of a traction-motor exciting-current and brake-horse-power limiter formed with three interconnected rectifying bridges, the outputs of the two bridges being connected in accord and coupled to the output of the third bridge and to one input of a comparison unit, while the inputs thereof are connected to an exciting-current transducer and to a braking intensity setter, the second input of the comparison unit being connected through a diode to the traction-motor reactive e.m.f. limiter.

Abstract: An electronic circuit designed to control entirely by electronic means the change from traction mode to braking mode and vice-versa of a separately excited DC machine and the forward and reverse operation of the motor as well as rheostatic braking. The chopper includes two main thyristors (T1) and (T2) and a single switch-off thyristor (T3) for the two main thyristors. The direction of current flow through the separate excitation winding (J) is determined by four thyristors (T5) to (T8).Application to railway traction.

Abstract: A three-terminal network which electrically senses the time at which the voltage applied to an AC induction motor is removed and concurrently therewith utilizes energy which was previously stored in a capacitor to effect eddy-current braking of the AC induction motor is disclosed.The disclosed system may be utilized to quickly, i.e., within two revolutions, brake a two-terminal shaded-pole induction motor, or a two-terminal unidirectional split-phase motor, or a three-terminal bidirectional split-phase motor.

Abstract: A drive and control arrangement for a mechanical eccentric press is disclosed. The arrangement includes a direct current electric motor connected to a reduction gear mechanism. An output shaft of the reduction gear mechanism is coupled to an eccentric such that the eccentric rotates with the shaft about a common axis. A connecting rod of the press is connected to the eccentric for pivotal movement about an axis parallel to and offset from the common axis of the shaft and eccentric. The arrangement includes a limit switch that is operated by a cam element adjustably mounted on the eccentric. An electronic control device is included and has a starter unit for supplying electric current to the motor, and a braking unit for short-circuiting the armature of the motor through a resistance in order to brake the motor and the press. The braking unit is actuated by the limit switch a predetermined period after the connecting rod has moved through its bottom dead center position.

Abstract: A linear actuator for providing a thrust force for actuating various movable members, such as, for example lever arms, cranks, slides and valve flaps. The thrust force is applied by an extension rod that is arranged within a housing so as to extend in an axial direction along the housing and out from the housing. The extension rod has a load connector mounted on the end outside of the housing for connection to the movable member to which the thrust force is to be applied. A drive screw is attached to the extension rod so that rotation of the drive screw is translated into an axial displacement of the extension rod. A drive motor serves to rotate the drive screw. Either when a blockage of the movable member occurs or when the extension rod has reached the end of its path of travel, any attempt for continued movement of the extension rod significantly increases the thrust force applied to the rod.

Abstract: A controlled current inverter motor control system including a controlled source of direct current for supplying a variable frequency inverter by way of a direct current link circuit which includes, within the link circuit, a selectively insertable dynamic braking resistive element. Upon a call for a dynamic braking mode of operation, the source of direct current is short circuited and the normal operational or running control of the motor is discontinued. Special circuitry is provided which then forces a special frequency control of the inverter to thus control the angle between the motor flux and motor current to a prescribed value proportional to the extant value of a motor operating parameter (motor current or motor flux) prior to the insertion of the dynamic braking resistive element into the link circuit.

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: The circuit effects a changeover from the traction configuration to the braking configuration or vice-versa in less than one millisecond. It includes the field winding (3) of the motor (1) disposed between a traction thyristor (12) and a main chopper (13) followed by a traction diode (14) and the armature of the motor, the field winding being in parallel with a free-wheeling diode (D5) and a shunt thyristor (THS).

Abstract: A DC motor control circuit for providing improved starting and stopping control is provided. The control circuit includes a DC motor that is driven in response to an operating voltage applied thereto. A shunting element is adapted to define a current path in parallel with the DC motor to selectively shunt the operating voltage applied to the DC motor. A DC supply is provided for producing a DC signal, and a constant voltage supply circuit is coupled intermediate the DC supply and the parallel connection of the shunt element and DC motor to selectively apply a constant operating voltage to the DC motor. A control circuit is provided for coincidentally applying a control signal to the constant voltage circuit and to the shunt element to effect a coincident shunting of the operating voltage applied to the DC motor and a cutting-off of the application of the operating voltage to the DC motor.

Abstract: There is disclosed a programmed microprocessor control apparatus and method for a transit vehicle electric motor through operation of a chopper apparatus. The microprocessor program controls the motor braking effort in brake mode through operation of the brake resistors and the motor tractive effort in the power mode through the motor field shunt operation.

Abstract: Disclosure is made of a digital control device intended to control thyristor-pulse d.c. regulators and comprising a master oscillator whose output is connected to an input of a clock pulse counter. A multidigit logic output of the clock pulse counter is connected to two control channels, each comprising in series a matching decoder, a reversible counter, a distributor, a comparator, a digital-analog converter, a coder, and a control decoder. Multidigit inputs of the control decoders of each control channels are connected to a multidigit output of a binary counter. The binary counter has its single-digit input and its multidigit input connected to an output of a pulser and multidigit output of a control unit, respectively. An input of the control unit is connected to a velocity transducer, and its reset output is connected to reset inputs of the master oscillator, a clock pulse generator, the clock pulse counter, the reversible counters, the pulser, and a voltage transducer.

Abstract: A circuit for electronically braking an AC motor. The circuit includes a controlled rectifying means for applying DC to the motor and a control means for turning the rectifying means on after deactuation of the motor for a timed interval determined by the charging rate of a timing capacitor through a variable resistance.