Abstract: An apparatus comprising, in combination, an AC motor, a solid state switch controlling the AC motor, the solid state switch switchable between an on state in which an electric current flows through the solid state switch and an off state in which electric current does not flow through the solid state switch, the solid state switch characterized by a turn off time such that, when the solid state switch is switched between the on state and the off state, at least a portion of the electric current flows through the solid state switch during the turn off time, a first switch circuit for switching off the solid state switch to prevent the electric current from flowing to the AC motor, a diode bridge coupled across the AC motor, a second switch circuit for controllably switching the diode bridge between an active state in which electric current may flow through the diode bridge and an inactive state in which electric current may not flow through the diode bridge, a control circuit for controlling the second switch

Abstract: An electric vehicle drive train includes a controller for detecting and compensating for vehicle rollback, as when the vehicle is started upward on an incline. The vehicle includes an electric motor rotatable in opposite directions corresponding to opposite directions of vehicle movement. A gear selector permits the driver to select an intended or desired direction of vehicle movement. If a speed and rotational sensor associated with the motor indicates vehicle movement opposite to the intended direction of vehicle movement, the motor is driven to a torque output magnitude as a nonconstant function of the rollback speed to counteract the vehicle rollback. The torque function may be either a linear function of speed or a function of the speed squared.

Abstract: A motor controller comprises a plug detect circuit which detects "continuous" plug diode conduction during plug braking. The plug detect circuit detects "continuous" plug braking by detecting when a plug diode is or is not conducting current throughout substantially the entire time that a power MOSFET controlling the plug braking is conductive in one pulse width modulated MOSFET switching cycle. Continuous plug detection facilitates the motor controller's controlling a vehicle so that the vehicle has a more constant and smooth plug braking deceleration and subsequent powered acceleration in the opposite direction. According to another aspect of the invention, a motor controller comprises a POT HI and a POT LO driver circuit. The POT HI and POT LO driver circuits allow the detection of faults in throttle devices and the connections of the throttle devices to the POT HI and POT LO driver circuits.

Abstract: The present invention features an improved technique for slowing and stopping a vehicle having an electric service motor, a mechanical parking brake, and a deadman's switch for engaging the mechanical brake. The method of the invention improves the efficiency of the braking procedure. The braking method initially determines if the deadman's switch is engaged. If it is, then the electric service motor is plugged at a predetermined minimum plug rate until the vehicle slows to a specified velocity. When the specified velocity is reached, the plugging operation is terminated. The mechanical brake is then engaged to slow the vehicle to a halt. When the vehicle comes to a halt, the parking brake remains engaged. The invention also improves safety by increasing the controlled rate of plugging to a maximum value in the event that the deadman's switch is off.

Abstract: The present invention features an electric motor control system combination with at least one electric motor having a field winding and an armature winding connected in series. The system also includes a first power terminal, a second power terminal, a current-limiting resistor, and a current sensor. The current-limiting resistor and the current sensor are connected in series between the first power terminal and the second power terminal. A contactor has a contact operable to shunt the current-limiting resistor. A microcomputerized control connected to the contactor and the current sensor governs the contractor to shunt the current-limiting resistor when the electric motor is not in a plugged condition. The contactor is operative when the current sensor detects a substantially zero current through the electric motor.

Abstract: Apparatus for inhibiting high torque created by the application of reverse voltage to a conventional motor with a field coil and armature operating in the opposite direction comprising a pair of drive resistors in series with the motor, a corresponding normally open contact connected in parallel to each respective drive resistor, an energizing coil corresponding to each contact, a timing circuit and an inhibitor circuit. During high speed forward operation, both coils are energized, closing both contacts, shorting out both drive resistors and maximizing motor voltage. When reverse operation is desired, a reverse voltage is applied across the armature, resetting the timing circuit and activating the inhibitor circuit. The inhibitor circuit will deenergize the coils, opening the contacts and remove the short across the drive resistors and thus reduce the reverse voltage being applied and permit gradual deacceleration.

Abstract: A motor control circuit provides reduced stopping time. The circuit utilizes n rotational signals whose relative phase differences are proportional to the rotational speed of the motor. Inverted logic signals are formed of these n signals. Circuitry for discriminating the direction of the motor and for determining from the n signals n-1 and/or n inverted signals, the initial change of any of the signals following a reversal of the motor. Upon determining the initial change, a signal is supplied to the motor drive circuit to cause the motor to de-energized. A specific circuit for holding the motor in a stopped condition is disclosed.

Abstract: Apparatus for inhibiting high torque created by the application of reverse voltage to a conventional motor with a field coil and armature operating in the opposite direction comprising a pair of drive resistors in series with the motor, a corresponding normally open contact connected in parallel to each respective drive resistor, an energizing coil corresponding to each contact, a timing circuit and an inhibitor circuit. During high speed forward operation, both coils are energized, closing both contacts, shorting out both drive resistors and maximizing motor voltage. When reverse operation is desired, a reverse voltage is applied across the armature, resetting the timing circuit and activating the inhibitor circuit. The inhibitor circuit will deenergize the coils, opening the contacts and remove the short across the drive resistors and thus reduce the reverse voltage being applied and permit gradual deacceleration.

Abstract: A motor drive control that permits a DC electric motor to be rapidly driven and accurately stopped at predetermined stop positions is disclosed. An indexer (V) generates a deceleration point signal at a deceleration point that occurs before a predetermined stop point of load (VI) and a stop point signal at the stop point corresponding to a predetermined destination of the load (VI). A rotational direction detector (III) detects the rotational direction of the motor (IV) as the motor (IV) passes the stop point and produces a rotational direction signal representing the rotational direction of the motor (IV). A rotation control circuit (I) generates a drive signal in response to movement and movement direction signals; a deceleration direction signal in response to the deceleration point signal; an inhibit signal in response to the stop point signal; and a decelerated drive signal representing a reverse rotational direction of the motor (IV).

Abstract: An apparatus for an electric drive vehicle which provides linear deceleration via electrical braking. The apparatus monitors vehicle speed and adjusts the duty cycle of a chopper circuit according to look-up tables. These table correlate vehicle speed and desired deceleration rate to braking torque, thereby enabling the apparatus to maintain a preselected deceleration through the entire stopping distance and to precisely position the vehicle.

Abstract: A recording or reproducing device in which current is supplied to the spindle motor which drives the disk to produce reverse torque in response to a stop signal when the disk is rotating. The beginning of reverse rotation is detected and the supply interrupted in response thereto.

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 method for operating an electronic control system for an operator controlled, electrically driven vehicle. The vehicle being powered by a direct current electric traction motor. The electronic control system includes a power source, a variable mark-space ratio power regulator responsive to a motor current command signal developed in response to the position of an accelerator, a direction selection means for providing signals indicative of the direction of motion of the vehicle, and a braking signal responsive to brake position. The electronic control system implements operation of the motor automatically in a propulsion mode, a regenerative mode, and a plug mode. The propulsion mode is either a series connected mode or a separately excited mode. The regenerative mode simulates the retarding effects of an internal combustion engine driven vehicle, while recover the kinetic energy of the vehicle by the generation of current to recharge the power source.

Abstract: A braking method for DC motor of the present invention is applied to a pulse-driven DC motor. A counter electromotive force of reverse polarity to driving pulses which is generated by induction at the winding of the DC motor is charged in a capacitor. The charged counter electromotive force is fed to the winding of the DC motor during the time that the driving pulses are not fed to the motor, so that plugging is applied to the DC motor. Thus, an external power source for plugging is not necessary, and power consumption is reduced and the construction of the braking circuit becomes very simple. Also, the driving period and the plugging period have a complementary relationship therebetween, thereby enabling the accurate controlling of the rotational speed of the DC motor with a very simple circuit.

Abstract: An improved H-bridge power amplifier for controllably driving a dc motor is presented. The motor is connected in the center of the H-bridge in conventional manner. The H-bridge includes a current sense resistor placed between the power supply and a common tie point of the upper transistors of the bridge. Free wheeling diodes are connected from the motor directly to the power supply. This arrangement allows current to flow through the current sense resistor only when one of the upper transistors is on. The power amplifier is operated by selecting an appropriate pair of upper and lower transistors on opposite sides of the bridge so as to cause the current to flow through the motor in a desired direction. Both the upper and lower transistors of the selected pair are held ON until the current as sensed in the current sense resistor equals or exceeds a specified value, typically a desired current level.

Abstract: A drive motor control device for a video disk player or the like operates to brake the motor by driving it reversely upon reception of a rotation termination signal, until it is detected that the motor has stopped and rotates reversely. The motor is then driven forwardly for a predetermined time before being allowed to rotate freely to a stop.

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: The invention pertains to a control system (46) for controlling the supply of power to a motor (12) to produce plugging electrical braking and current limit control, including a circuit (60) for controlling the direction of energization of the motor (12), a circuit (88) for generating digital numbers representing command motor speeds, a circuit (14) for generating a data signal representing a plugging condition, a programmable data processor (18) for generating pulse trains in dependence on the plugging condition, and a power transistor element (40) for coupling power to the motor (12) in response to the pulse trains. By using state-of-the-art digital, integrated circuit and software technology, prior, essentially linear or discrete component technology, which is relatively unreliable, expensive and slow, need not be used.

Abstract: A plugging defeat system for use with a reversible electric motor having a motor shaft. A slipping clutch-type mechanism is used to sense the speed and direction of the motor and to selectively open forward or reverse enabling switches when the motor reaches a predetermined speed. If operating in the forward direction, the clutch mechanism will open the reverse enabling switch, once the predetermined speed is reached, preventing motor reversal until the speed has fallen to a safe level, and vice versa.

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 machine includes a rotor with a magnetic field produced therein that is fixedly oriented with respect to the rotor. The rotor is rotatably mounted within a stator which has a plurality of windings. Means are provided for applying voltage pulses to the stator windings. When voltage pulses are applied to the stator windings, there is a torque due to the interaction of a magnetic field produced in the stator windings and the rotor magnetic field that causes the rotor to rotate. A control system responds to voltage induced across unpowered stator windings by the rotating rotor magnetic field and controls application of the voltage pulses to the stator windings. The voltage pulse sequence, frequency, and duration are determined by the control system. The control system may also adjust the voltage pulse amplitude. The voltage pulses are applied to the stator windings in such a way that the machine operates at optimum efficiency and at a selectable speed over a wide range of loads and/or line voltages.

Abstract: An electrical braking control circuit for use in a control system for a direct current traction motor which may be employed, for example, to propel an electrically driven vehicle. The electrical braking controller of the invention initiates electrical braking in a plug mode of braking and then, when conditions are suitable for regenerative braking, causes a transition to regenerative braking, followed by return to a plug mode of braking whenever regenerative braking can no longer be efficiently achieved, all of which is carried out smoothly and efficiently without unduly wasting regenerative power.

Abstract: An electric vehicle control apparatus fixed onto an electric vehicle body and including at least a main semiconductor device and a flywheel diode comprises a base member thereof fixed onto said vehicle body being in close contact therewith, a heat sink made of a metallic plate and fixed onto a portion of said base member through a thin sheet of an insulating material intervening therebetween, at least two pellets fixed directly onto said heat sink which pellets constitute at least said main semiconductor device and said flywheel diode, connecting terminals each thereof mounted on each of said pellets, and at least one auxiliary electric device fixed onto said heat sink.

Abstract: A system for accurately stopping a motor operated positioning device permits satisfactory motor tolerance limits for economical production by incorporation of a processor controlled motor plugging routine. The plugging routine includes an initial reverse polarity pulse to the motor of a duration sufficient to brake an ideal motor operating in the device. To accommodate motor characteristics within tolerance limits, a plurality of alternating bursts of positive and reverse polarity are applied to the motor following the initial pulse. Each of the alternating bursts is for a duration less than the system response time.

Abstract: A machine includes a rotor with a magnetic field produced therein that is fixedly oriented with respect to the rotor. The rotor is rotatably mounted within a stator which has a plurality of windings. Means are provided for applying voltage pulses to the stator windings. When voltage pulses are applied to the stator windings, there is a torque due to the interaction of a magnetic field produced in the stator windings and the rotor magnetic field that causes the rotor to rotate. A control system responds to voltage induced across unpowered stator windings by the rotating rotor magnetic field and controls application of the voltage pulses to the stator windings. The voltage pulse sequence, frequency, and duration are determined by the control system. The control system may also adjust the voltage pulse amplitude. The voltage pulses are applied to the stator windings in such a way that the machine operates at optimum efficiency and at a selectable speed over a wide range of loads and/or line voltages.

Abstract: A control apparatus for an electric motor vehicle includes a control system to increase the duty cycle of a chopper circuit driving an electric drive motor of the vehicle when a spontaneous backward movement takes place upon starting of the vehicle at an uphill gradient, thereby to increase the armature and field current of the drive motor and hence the counter current braking effort or so-called plugging effort. The control apparatus assures a reliable starting of the vehicle even at an uphill gradient road.

Abstract: A disc record player in which a turntable is driven by a motor comprising a rotor magnet having plural magnetic poles arranged separately along the periphery of the turntable, stator coils disposed in the magnetic field of the rotor magnet and Hall-effect elements sequentially coupled magnetically to the poles of the rotor magnet for generating output signals having polarities corresponding to the polarities of the poles of the rotor magnet, and causing the rotor magnet to rotate by supplying the output signals of the Hall-effect elements to the stator coils, wherein a first and a second speed detecting coils for generating signals having phases different from each other are disposed in the magnetic field of the rotor magnet, wherein the output signals of the first and second speed detecting coils respectively turn the gate circuit off and on and when the turntable is to be stopped, the gate circuit is turned on by the output signal of the second speed detecting coil, and wherein the rotation of the turntable

Abstract: In cases of subjecting an electric motor operated vehicle to electric braking, regenerative braking is performed during the first stage of the braking operation thereby supplying the armature current to the battery as a load, and a plugging operation is performed during the last stage thereof to complete the braking operation, whereby the efficiency of operation is enhanced by conserving the armature current to extend the traveling distance of the vehicle per charge of the vehicle battery, and the generation of excessive heat in the motor is suppressed.

Abstract: A pulse controller for a reversible d.c. series motor is provided, in place of the conventional freewheel diode across the armature and field and plugging diode across the armature, with a unidirectional current path connected across the armature and field and containing sufficient impedance to prevent build-up of motor current in interpulse periods when the motor is in a plugging mode, and switch means for shorting out the impedance during normal motoring.

Abstract: There is disclosed a programmed microprocessor control apparatus and method for determining the electric brake current build-up for regenerative braking effort with a series motor. The microprocessor program determines the current build-up by controlling the chopper operative with the electric motor of a transit vehicle.

Abstract: A plugging control circuit in a silicon controlled rectifier (SCR) control for a series-connected direct-current vehicle-propulsion motor. The plugging control prevents the main SCR from pulsing when plug current is high, restarts the SCR pulsing when the plug current decays but with a reduced pulse width, and delays application of power through the main SCR for a time to allow the vehicle to first come to a halt before power is applied to move the vehicle in the opposite direction.

Abstract: A circuit for use in a silicon controlled rectifier (SCR) control for direct current powered loads wherein the commutating voltage on the commutating capacitor is used to generate a gate pulse for the commutating SCR to thereby turn the main SCR off at a fixed and predetermined time after it has been turned on. The commutating voltage in the commutating capacitor is also monitored during charging thereof and the gate pulse for the commutating SCR is generated prior to the predetermined time in case the peak current through the main SCR reaches a predetermined excessive value. The gate pulse is also generated prior to the predetermined time during plugging or low-speed operation of motors.

Abstract: A pulse width modulation chopper controller for a D.C. traction motor has plug sensing means which monitors the voltage across the motor armature on a pulse-by-pulse basis and is responsive, only when the power switch is turned on, to the motor acting as a generator to limit the "on-time" of the power switch before current of high magnitude can flow in the motor.

Abstract: A DC motor control system is provided which is useful for plugging action in an electric-powered vehicle. In the system, a saturable transformer is employed as a means of increasing the reverse biasing time of a thyristor without increasing the capacity and voltage proof of a capacitor. As a result, an increased biasing time of the thyristor can be ensured.

Abstract: A control system for a DC electric traction motor which eliminates cogging of the motor during transition from a driving to a plugging mode. The system incorporates apparatus for comparing motor armature current to a plugging current reference voltage which voltage is initially applied as a ramp function to thereby provide a smooth transition into braking.

Abstract: A method and apparatus for sensing plugging of a DC electric motor comprising logic circuitry responsive to a direction change command for initiating a plugging signal and additional logic circuitry for maintaining said plugging signal as a function of the percentage on time of a variable time ratio switch supplying power to the motor. Inhibit circuitry is provided to override the plugging signal under operator selected conditions.

Abstract: An electrical supervisory circuit arrangement, as for detecting faults such as yarn breakage in a circular knitting machine, comprises a number of channels each responsive to a particular type of fault signal in the machine. Each channel comprises a bistable transistor circuit which is switched in response to the particular fault condition to be detected and, when so switched, energises a warning light. In addition, all the bistable circuits are connected in common to an output transistor which is thus switched when any of the bistable circuits detects a fault. The output transistor controls two relays, one of which disconnects the forward-current supply to the machine and the other of which temporarily provides a reverse-current supply for braking the motor.

Abstract: In a control circuit for an electrically driven vehicle, there is a thyristor chopper circuit which sets the current flow in a traction motor to a demanded level. The motor is capable of driving the vehicle forwardly or in reverse, and is also capable of effecting electrical braking. Whenever the motor is switched from its forward drive to its forward braking condition, or vice versa, the demand signal is set at a low level for a predetermined period.

Abstract: An operating apparatus for electrically driven vehicle, for example a fork lift truck, of the type that has an electric motor connected to a DC source via a chopper circuit. The apparatus includes a relay for supplying DC power to said motor, a switching element for operating the relay and a transistorized detector circuit pararelly connected to said switching element which sense the normal operation of the chopper circuit, and makes the switching element non-conductive in the event of malfunctioning. Further, the apparatus includes a chopper control circuit for controlling the chopper circuit effectively and a overcurrent detector circuit for control chopper current by detecting the overcurrent.