Abstract: A trolley interfacing device for interfacing a traction load to a voltage source is presented. The trolley interfacing device includes a first charging unit coupled in parallel to the voltage source. Further, the trolley interfacing device includes a second charging unit coupled in parallel to the traction load, where the second charging unit includes at least one inductor. Also, the trolley interfacing device includes a pre-charging unit coupled in parallel to the second charging unit and configured to pre-charge the first charging unit with a voltage across the at least one inductor prior to electrically coupling the first charging unit to the voltage source. In addition, the trolley interfacing device includes a voltage converting unit disposed between the first charging unit and the second charging unit and configured to step down a voltage provided by the voltage source to the traction load.

Abstract: A stator phase circuit for an electric machine includes a phase winding circuit including a plurality of series coupled sub-winding circuits, each sub-winding circuit includes a respective sub-winding coupled in parallel across a respective first controllable switch.

Abstract: A stator phase circuit for an electric machine includes a phase winding circuit including a plurality of series coupled sub-winding circuits, each sub-winding circuit includes a respective sub-winding coupled in parallel across a respective first controllable switch.

Abstract: A differential pressure sensor apparatus for use in a fuel delivery system measures the differential pressure of the fuel between a point immediately upstream and a point immediately downstream of a fuel monitor element. The differential pressure sensor apparatus uses an electronic transducer to monitor differential pressure and may be used with interlocks to shutdown fuel delivery if the measured value of the differential pressure is above a predetermined threshold value and to notify an operator of the fuel delivery system of such an increase in the differential pressure.

Abstract: A control device and a method of stopping the spindle motor or an optical disc system. The control device primarily includes an optical disc control chip, a motor driving circuit and a spindle motor. The optical disc control chip generates and delivers a spindle motor control signal to the motor driving circuit for driving the spindle motor into rotation. During a first period, the spindle motor control signal level is controlled to produce the largest reversing torque permitted by the spindle motor for braking purpose. During a second period, the spindle motor control signal level decreases gradually to approach to a lock level that is smaller than that for actuating the spindle motor, so that the reversing torque is also decreasing gradually.

Abstract: A motor control circuit provides series or compound excitation during starting and shunt excitation during normal running. A switch responsive to the motor speed, the armature current, the armature EMF, or the like, includes terminals connected to the series winding and a series winding bypass to permit switching between a compound series and a shunt configuration. In addition, a tap may be provided on the series winding for providing intermediate characteristics, and separate switches for the series and shunt field windings may also be provided.

Abstract: A reversible motor is coupled to the stern leg of a watercraft for angulating the leg up and down through a trim and tilt range. A manually settable device provides a voltage signal corresponding to the desired trim angle and a position sensor provides a voltage signal corresponding to the present stern leg position. A first comparator changes the state of its output if the difference between the signals has one polarity and a second comparator changes state for the opposite polarity. The state changes turn on one of two transistor switches which provide an up or a down signal, respectively, to a motor control circuit for causing the motor to run until the difference is nulled. When the active transistor switch turns off, the other delivers a momentary pulse for plugging the motor.

Abstract: A pulse control circuit for a d.c. series motor having an armature and two oppositely-wound field windings, comprises a contactor in series with the motor, two main thyristors each connected in series with the armature and a respective one of the field windings, means for controlling the mark-to-space ratio of conduction of each thyristor, one or other of the main thyristors being brought into operation in dependence upon the desired direction of drive of the armature, means for sensing failure of commutation of the main thyristor, and means for causing opening of the contactor in response to such sensing. The control circuit includes means for firing the other main thyristor immediately commutation failure is sensed, thereby to limit the net field flux and motor torque in the period during which the contactor is opening.

Abstract: A feature of this invention is the provision of a reversible, D.C. shunt field motor having an armature and two separate field windings, each field winding being capable of producing rated field flux. The motor is capable of bidirectional rotation having one field energizable for CW rotation and the other field energizable for CCW rotation. A servo system couples the two field windings and has only one active control element in the high current armature circuit to control the magnitude of the armature current, and two low power amplifiers, each low power amplifier having an active control element and each controlling the magnitude of the field flux (and thereby the magnitude of armature current under certain circumstances) in a given respective direction.

Abstract: A pulse control circuit for a three-terminal d.c. series motor having an armature and two oppositely-wound field windings comprises a respective main thyristor in series with each field winding, one or other of the main thyristors being operated at a variable mark-to-space ratio to energize the field winding appropriate to drive the motor in a selected direction. The circuit includes switch means operable to connect the motor in a regenerative braking mode in which the armature and each field winding are connected to the battery in series with a freewheel diode and with a diode across the motor so that charging current can flow from the motor to the battery during regenerative braking. Circuit means are provided to effect initial energization of at least one field winding when the circuit is first switched to the regenerative braking mode.

Abstract: An electromagnetic stepping motor has a stator with an armature having the shape of an isosceles trapezoid the base of which is interrupted by a central gap and which is provided with three pole faces. The rotor comprises a permanent magnet. The stator comprises two coils one of which is located between a pole face opposite said gap and one of the other two pole faces. The other coil is located between the pole face opposite said gap and the other of said other two pole faces. When a current passes through the coils, the rotor is subjected to magnetic fields having directions which are oblique to each other and which are symmetrical with respect to a diameter of the rotor. The sense of the coil currents determines the sense of the fields. The arrangement is such that one can create in the zone of the rotor a resultant magnetic field which can extend in any one of four different directions dependent on the sense of the currents passing through the coils.

Abstract: An electromagnetic stepping motor has a stator with an armature having the shape of an isosceles trapezoid the base of which is interrupted by a central gap and which is provided with three pole faces. The rotor comprises a permanent magnet. The stator comprises two coils one of which is located between a pole face opposite said gap and one of the other two pole faces. The other coil is located between the pole face opposite said gap and the other of said other two pole faces. When a current passes through the coils, the rotor is subjected to magnetic fields having directions which are oblique to each other and which are symmetrical with respect to a diameter of the rotor. The sense of the coil currents determines the sense of the fields. The arrangement is such that one can create in the zone of the rotor a resultant magnetic field which can extend in any one of four different directions dependent on the sense of the currents passing through the coils.

Abstract: A linear servo circuit for A.C. motors is disclosed. The servo circuitry is used in a magnetic tape transport to control the motor which operates a tape reel on which the magnetic tape is stored. The servo circuitry develops two complimentary saw-tooth voltage waveforms synchronized to the sinusoidal A.C. line voltage. One saw-tooth waveform is used to control the motor in the forward direction and the other saw-tooth waveform is used to control the motor in the reverse direction. Comparator circuitry compares the saw-tooth waveforms to a D.C. control voltage which is proportional to the angular position of an arm that controls the tension of the magnetic tape. The comparator circuitry provides a control pulse to a photodiode when the saw-tooth waveform exceeds the D.C. control voltage. Light pulses from the photodiode impinge on a light sensitive SCR which in turn triggers a triac to apply power in the forward or reverse direction to the A.C. tape reel motor.

Abstract: Gate-turn-off silicon controlled rectifiers (GTO's) are selectively rendered conductive to control the direction of rotation of a bi-directional motor. To this end a digital logic network is responsive to either one or both of a pair of remotely located switches being operated to either a first or a second condition, for controlling a transistorized gate signal generating network to apply an operating voltage to the gate electrode of the appropriate one(s) of the GTO's. The gate signal generating network includes circuitry for grounding the gates of the GTO's, turning them off if on and thereby inhibiting operation of the motor, whenever either of two operating conditions obtains.

Abstract: Beds, such as hospital beds, in which at least some portion of the bed is movably actuated by an electric motor (or motors) are provided with a control circuit to determine proper energization of the motor from an AC power source. Since the AC signal from the power source could be harmful to the person selecting a desired direction of travel of the movable portion of the bed, the selecting portion of the control circuit is isolated by appropriate transformers from the power portion that supplies the motor. Bidirectional switching devices, such as triacs, are utilized to convey the power to the motor. Other bidirectional switching devices, such as triacs, are used to gate the power handling triacs through appropriate gating transformers. A phase shifting arrangement is utilized in connection with the gating transformers to provide proper commutation of the power handling triacs.