Locally Closed Armature Circuit Patents (Class 318/379)
  • Patent number: 6118242
    Abstract: A travel-limit circuit having a DC motor for a lens by which the endurance of the motor can be improved while at the same reducing the rebound due to the inertia of the moving body at a travel extremity. The travel-limit circuit has a lens motor that drives, e.g., zoom lens groups. Limits which detect whether the lens group has reached their travel extremities at which mechanical stoppers are provided. The motor driving circuit, which drives the lens motor and the limit switches, activates a short break by short circuiting the pair of input terminals on the lens motor via diodes while cutting current flow from the motor driving circuit for the lens motor upon detection that the lens groups have reached their travel limit.
    Type: Grant
    Filed: December 22, 1998
    Date of Patent: September 12, 2000
    Assignee: Asahi Seimitsu Kabushiki Kaisha
    Inventors: Toru Shikano, Masayuki Arai
  • Patent number: 6013993
    Abstract: A braking circuit for a universal motor is proposed, in which, during braking, the at least one field winding is connected in series with the armature by means of a semi-conductor switch, preferably a field effect transistor or a thyristor. Since the semiconductor switch can also be switched intermittently and with a time delay, not only is it possible to regulate the braking current simply, but there is also a reduced formation of sparks at the collector. The reduction in the contact erosion lengthens the service life and increases the reliability of the motor.
    Type: Grant
    Filed: May 26, 1995
    Date of Patent: January 11, 2000
    Assignee: Robert Bosch GmbH
    Inventor: Benedikt Barbisch
  • Patent number: 6008619
    Abstract: A drive current and a regenerative current are alternately applied to a motor during a PWM (pulse width modulation) time period. The regenerative current is produced by an electromagnetic induction of an armature and flows in the opposite direction as the drive current. Therefore, a rotating speed of the motor is reduced, so that a speed-reduction following characteristic for the motor is improved. By varying the duty factor, the lengths of time during which the drive current and the regenerative current are flowing can be controlled. Thus, the speed of the motor can be controlled.
    Type: Grant
    Filed: June 29, 1998
    Date of Patent: December 28, 1999
    Assignee: NEC Corporation
    Inventors: Makoto Murase, Kazunari Mizuguchi, Toshio Tsubota, Tatsuo Nishizawa
  • Patent number: 5982119
    Abstract: A motor drive apparatus used in a motor for controlling a rotor therein to rotate in regular and reverse directions includes a rotating direction detecting circuit for detecting a first direction in which rotor is rotating. A comparator compares a command signal with a reference signal to detect a second direction in which the rotor should rotate. A motor driver comprised of buffer amplifiers and power supply circuits is provided to rotate the rotor based on the command signal. A command signal generator produces a drive signal which is transferred to the power supply circuits through a switch when the first and second directions are both identical to the reverse direction.
    Type: Grant
    Filed: January 2, 1997
    Date of Patent: November 9, 1999
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuhiro Okada, Tadashi Itami
  • Patent number: 5875281
    Abstract: Direct current (DC) solid state series wound motor drives for hoist and crane applications. A microprocessor controlled electronic system is employed to control the speed, direction, acceleration and deceleration of a direct current DC solid state series wound motor drive for a hoist or a crane (bridge or trolley). The operation can be via an operator, radio remote, or computer communication link. The system requires a speed and direction command from the operator controls; it then configures the motor and varies the speed while offering certain protection circuits. The DC series wound motor drive includes a DC series wound motor comprising an armature and a series wound field that is supplied with DC voltage power from an external source. The DC voltage power supply can either be generated DC or rectified alternating current (AC). High speed insulated gate bipolar transistor (IGBT) switching elements are provided.
    Type: Grant
    Filed: July 24, 1997
    Date of Patent: February 23, 1999
    Assignee: Cableform, Inc.
    Inventors: Graham S. Thexton, John Aker
  • Patent number: 5782610
    Abstract: A method of stopping a scroll compressor that is driven by a 3-phase dc motor having 3-phase exciter windings is provided. The motor is energized by a 3-phase dc power that is produced from a dc power source through an electronic switching circuit. The switching circuit has three pairs of bridge-connected switching transistors whose switchings are individually controlled by a switching controller. One of each pair of the switching transistors belongs to a first transistor group that is connected to a positive terminal of the dc power source and the other belongs to a second transistor group that is connected to a negative terminal of the dc power source.
    Type: Grant
    Filed: November 27, 1996
    Date of Patent: July 21, 1998
    Assignee: Sanden Corp.
    Inventor: Hideo Ikeda
  • Patent number: 5760555
    Abstract: A motor drive unit is provided with a bridge circuit including series connected first and second MOS transistors, series connected third and fourth MOS transistors, a DC motor connected between a junction of the first and second MOS transistors and a junction of the third and fourth MOS transistors, a power supply line connected to the first and third MOS transistors and a ground line connected to the second and fourth MOS transistors. The state of the DC motor is controlled by on/off controlling the MOS transistors of the bridge circuit. The MOS transistors are controlled such that the motor is continuously short-circuited when a power is supplied to the motor drive unit and the motor is not driven.
    Type: Grant
    Filed: April 5, 1996
    Date of Patent: June 2, 1998
    Assignee: Nikon Corporation
    Inventors: Shozo Yamano, Nobuhiko Terui
  • Patent number: 5703450
    Abstract: A safety guard for a pedestrian-operated or riding machine having rotatable blades and incorporating a strip switch for disabling the motor of the machine upon sensing the presence of an operator's body part or other foreign object in contact with a side of the housing or between the housing of the machine and the ground. The strip switch is secured to the housing and is oriented to be actuated when the machine overruns or contacts a foreign object. Upon actuation, the strip switch disables operation of the motor to prevent the machine's rotating blades or other moving parts below the housing of the machine from striking the foreign object. Another approach to minimizing injury from machinery having rotatable blades is to provide a semi-rigid guard which is attached to the machine body and movable in a forward movement and away from the ground while preventing lateral movement of objects under the machine.
    Type: Grant
    Filed: June 19, 1996
    Date of Patent: December 30, 1997
    Inventor: Harold Josephs
  • Patent number: 5631528
    Abstract: A method for sensing motor commutation pulses during motor braking without creating negative voltages, which some junction isolated technologies substantially cannot tolerate. For instance, a commutation pulse sensing circuit containing junction isolated technology may only be able to detect commutation pulses intermittently. An H-bridge motor drive configuration is used to drive and brake a motor. High side clamp diodes are coupled between the motor terminals and a high potential source for high side braking of the motor. As an alternative to high side clamp diodes, any other suitable device may be used, including operating the pair of transistors in the upper portion of the H-bridge in an inverse mode. A commutation pulse sensing circuit is coupled to a terminal of the motor. The use of the high side brake clamp diodes avoids generating negative voltages at the motor terminals.
    Type: Grant
    Filed: May 4, 1995
    Date of Patent: May 20, 1997
    Assignee: Linfinity Microelectronics
    Inventor: Dan Agiman
  • Patent number: 5528115
    Abstract: An inductive load drive circuit for driving an inductive load, such as a motor, and for preventing charging of a power source by the back electromotive force of an inductive load. The inductive load drive circuit uses a battery as the power source for supplying power to the load. A first switching mechanism can serially connect and disconnect the inductive load and the battery. The first switching mechanism is controlled so that it disconnects the inductive load from the battery when the inductive load is in a condition in which the inductive load is able to generate back electromotive force or when the inductive load will be shifted to such a condition. Moreover, a bypass circuit can be used to consume the energy of the back electromotive force of the inductive load. A second switching mechanism is serially connected to the bypass circuit, with the serial combination of the second switching mechanism and the bypass circuit being in parallel with the power source.
    Type: Grant
    Filed: March 3, 1994
    Date of Patent: June 18, 1996
    Assignee: Nikon Corporation
    Inventor: Fumiya Taguchi
  • Patent number: 5488275
    Abstract: A control circuit for limiting the current flow to a direct-current driven motor, to reduce current spikes at motor start up, including a voltage-regulated, current-passing device for passing current from a direct voltage source to the motor, the device having a default configuration such as to permit full current flow there-across when the voltage is initially applied, a voltage drop device interposed the voltage source and the voltage-regulated, current-passing device responsive to the current flow to the motor and a variable-voltage output device responsive to the voltage drop developed in the voltage-drop device for providing a subsequently changing voltage for input to the current-passing device for limiting the current flow therethrough following initial application of the voltage.
    Type: Grant
    Filed: March 16, 1995
    Date of Patent: January 30, 1996
    Assignee: ETI Systems
    Inventor: Bill Tice
  • Patent number: 5471123
    Abstract: A control circuit for limiting the current flow to a direct-current driven motor, to reduce current spikes at motor start up, including a voltage-regulated, current-passing device for passing current from a direct voltage source to the motor, the device having a default configuration such as to permit full current flow there-across when the voltage is initially applied, a voltage drop device interposed the voltage source and the voltage-regulated, current-passing device responsive to the current flow to the motor and a variable-voltage output device responsive to the voltage drop developed in the voltage-drop device for providing a subsequently changing voltage for input to the current-passing device for limiting the current flow therethrough following initial application of the voltage.
    Type: Grant
    Filed: March 16, 1995
    Date of Patent: November 28, 1995
    Assignee: ETI Systems
    Inventor: Bill Tice
  • Patent number: 5461290
    Abstract: A control circuit for limiting the current flow to a direct-current driven motor, to reduce current spikes at motor start up, including a voltage-regulated, current-passing device for passing current from a direct voltage source to the motor, the device having a default configuration such as to permit full current flow thereacross when the voltage is initially applied, a voltage drop device interposed the voltage source and the voltage-regulated, current-passing device responsive to the current flow to the motor and a variable-voltage output device responsive to the voltage drop developed in the voltage-drop device for providing a subsequently changing voltage for input to the current-passing device for limiting the current flow therethrough following initial application of the voltage.
    Type: Grant
    Filed: January 3, 1994
    Date of Patent: October 24, 1995
    Assignee: ETI Systems
    Inventor: Bill Tice
  • Patent number: 5441298
    Abstract: An apparatus for stabilizing an active suspension system of an automotive vehicle is provided having a power source and a motor with a plurality of stator wires connected to the suspension unit for controlling the movement of the suspension. A controller is electrically connected to the motor and to the power source for developing current commands for input into the motor through the stator wires. The switch, electrically connected to the stator wires and the power source, connects the stator wires together in response to an interruption of the power source so that a high torque is developed in the motor for restraining the movement of the suspension unit.
    Type: Grant
    Filed: October 22, 1993
    Date of Patent: August 15, 1995
    Assignee: Ford Motor Company
    Inventors: John M. Miller, Richard J. Hampo, Roy I. Davis
  • Patent number: 5357182
    Abstract: A system for braking a wheeled vehicle when it is attempted to be moved outside of a defined perimeter wherein at least one wheel of the vehicle is mechanically coupled to a shaft carrying means to create upon rotation of the shaft, through electromagnetic action an electric current at a pair of terminals; circuit means, responsive to a predetermined signal, to short said terminals, thereby creating a counter electromagnetic force to inhibit rotation of said shaft and wheel coupled thereto to brake the latter; means to generate said predetermined signal; and means to radiate said signal locally along said perimeter.
    Type: Grant
    Filed: January 27, 1993
    Date of Patent: October 18, 1994
    Inventors: Steven M. Wolfe, John V. Biondo, Jr.
  • Patent number: 5306991
    Abstract: A window wiper comprising an arm having an end rotatably mounted near a window glass, a sliding member reciprocally slidable along the sliding member, a loop-like control cable connected to the sliding member, a mechanism for actuating the arm to reciprocally rotate, and a mechanism for actuating the control cable to reciprocally circulate in synchronized with the motion of the arm, whereby the window glass can be swept with single arm.
    Type: Grant
    Filed: November 25, 1992
    Date of Patent: April 26, 1994
    Assignee: Nippon Cable System Inc.
    Inventor: Kazuhiro Suzuki
  • Patent number: 5164642
    Abstract: The invention is a chopper control for electric cars. In the control device, the currents of the armatures A1 and A2 of electric car driving shunt motors connected to a power source L are controlled by first chopper devices CH1 and CH2, the currents, in the forward direction, the field coils SF1 and SF2 of the shunt motors are controlled by a second chopper device FCH1, and the currents, in the reverse direction, of the field coils are controlled by a third chopper coil FCH2.
    Type: Grant
    Filed: August 5, 1991
    Date of Patent: November 17, 1992
    Assignee: Mitsubishi Denki K.K.
    Inventor: Masahiro Ashiya
  • Patent number: 4990837
    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.
    Type: Grant
    Filed: October 25, 1989
    Date of Patent: February 5, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Chikato Ishitobi
  • Patent number: 4922161
    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.
    Type: Grant
    Filed: March 31, 1989
    Date of Patent: May 1, 1990
    Assignee: Malcolm T. Gilliland
    Inventors: Malcolm T. Gilliland, Charles L. Warner, II
  • Patent number: 4767970
    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.
    Type: Grant
    Filed: December 22, 1986
    Date of Patent: August 30, 1988
    Assignee: Ampex Corporation
    Inventor: David R. Rodal
  • Patent number: 4545004
    Abstract: A transistor bridge driver circuit having reduced operating losses, comprising a driver transistor connected to supply drive current to diagonally opposed bridge transistors and an auxiliary transistor effective when biased conductive to divert driver current away from one of the diagonally opposed bridge transistors. Switching losses are minimized because the bridge is operated in the one quadrant control mode and driver losses are minimized because one driver circuit controls the conduction of two diagonally opposed bridge transistors.
    Type: Grant
    Filed: March 22, 1984
    Date of Patent: October 1, 1985
    Assignee: General Motors Corporation
    Inventors: Alexander Kade, Thomas A. Radomski
  • Patent number: 4529919
    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.
    Type: Grant
    Filed: January 5, 1983
    Date of Patent: July 16, 1985
    Assignee: Towmotor Corporation
    Inventors: Grant C. Melocik, William Pickering
  • Patent number: 4430604
    Abstract: A switch is disclosed which includes both a switching assembly and a bridge rectifier, the switch assembly including contacts for connecting a DC motor such as the motor of an electric lawn mower, to AC supply lines or for short-circuiting the motor to rapidly stop rotation of the motor. Diodes of the bridge rectifier have terminals which are directly secured to portions of metal members which also carry contacts of the switch and/or serve as terminals for connection to the motor or the supply lines.
    Type: Grant
    Filed: March 24, 1982
    Date of Patent: February 7, 1984
    Assignee: Echlin Inc.
    Inventors: Ernest L. Loganbill, William E. Taylor
  • Patent number: 4422021
    Abstract: To provide for high efficiency of recuperation of energy stored in the rotating and electromagnetic system of a dynamo electric machine, upon dynamic braking thereof, in which the dynamo electric machine is connected in a chopper-controlled series circuit, a field diode (10) is connected across the field winding (11); a controlled switch (18), for example a transistor or a thyristor, is connected to the junction between the field winding (11) and the aramature (12, 13) and a return line (N) to a storage battery, the controlled switch being controlled to close by a control circuit (19) which opens a brake switch (16) connected between the battery and the dynamo electric machine series circuit under motor operating conditions, to provide for continued current flow through the field, which then is reversely connected by a field reversal switch (8, 9), with continued current flow being maintained by a free-wheeling diode (10) connected across the field.
    Type: Grant
    Filed: November 5, 1981
    Date of Patent: December 20, 1983
    Assignee: Robert Bosch GmbH
    Inventor: Albrecht Schwarz
  • Patent number: 4420716
    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.
    Type: Grant
    Filed: December 22, 1980
    Date of Patent: December 13, 1983
    Assignee: General Research of Electronics, Inc.
    Inventors: Kazuyoshi Imazeki, Masao Nakano
  • Patent number: 4401927
    Abstract: A direct current motor includes a chopper in series with the field coil of the motor to regulate the current flowing through the armature of the motor during electrical braking when the motor functions as a generator to produce current. In addition, a shunting device is connected to the field coil to regulate the current flowing through the coil so that it is maintained at a value less than the armature current.
    Type: Grant
    Filed: April 16, 1981
    Date of Patent: August 30, 1983
    Assignee: Societe CEM-Compagnie Electromecanique & CIE SNC.
    Inventor: M. N'Guyen U. Thuy
  • Patent number: 4396876
    Abstract: A motor control apparatus which includes a pulse generator for providing a first signal for specifying the operational condition of a motor, and a motor driver for providing a second signal for driving the motor when the first signal is at a first level and providing a second signal when the first signal is at a second level. The motor control apparatus further includes a comparator, which compares the back electromotive force of the motor with a reference level when the first signal is at the second level and providing a third signal when the back electromotive force is within a given level range prescribed by the reference level. A switch circuit closes a circuit path through which a back electromotive force current produced by the back electromotive force flows when the second and third signals are provided, thereby applying electromagnetic braking with respect to the rotation of the motor.
    Type: Grant
    Filed: April 7, 1981
    Date of Patent: August 2, 1983
    Assignee: Olympus Optical Co., Ltd.
    Inventors: Hitomi Tojiki, Teruo Iwasawa
  • Patent number: 4347466
    Abstract: D.C. motor control utilizing an input transformer with magnetic leakage and current control to allow power, whether generated occasionally or continuously from the motor (induced by load inertia and the like) to be smoothly returned back into the main A.C. power line, consistent with continuous smooth speed control (low form factor), low heating and low cost.
    Type: Grant
    Filed: December 27, 1979
    Date of Patent: August 31, 1982
    Assignee: Vee Arc Corporation
    Inventor: Allen E. Ottoson
  • Patent number: 4319171
    Abstract: A motor control device includes a bridge circuit having semiconductor switching elements disposed in each arm thereof and being adapted for the connection of a motor between pairs of arms. The semiconductor switching elements are selectively rendered conductive to alternately drive the motor in forward and reverse directions, and certain ones of a semiconductor switching elements may be simultaneously rendered conductive to form a closed loop which short-circuits the motor and causes dynamic braking. The motor control device is capable of instantaneously stopping the rotation of the motor and is capable of rapidly reversing the motor's direction of rotation. The device is particularly useful in an automatic focusing apparatus or an automatic diaphragm setting apparatus in a camera.
    Type: Grant
    Filed: July 11, 1980
    Date of Patent: March 9, 1982
    Assignee: Nippon Kogaku K.K.
    Inventor: Ryuzo Motoori
  • Patent number: 4267492
    Abstract: A direct current motor control circuit in which the armature is arranged for reversible connection in a main path for current to flow from a first supply terminal to a second supply terminal through the armature and a current chopper. A pair of switches between which the armature is connected are controllable to effect this reversible connection in the drive mode and to connect the armature across a bridge to permit return current to flow from the second terminal, in either direction through the armature toward the chopper in a regenerative mode, one or more diodes being provided for completing a return path for the return current to flow to the first terminal.
    Type: Grant
    Filed: October 31, 1978
    Date of Patent: May 12, 1981
    Assignee: Lansing Bagnall Limited
    Inventor: Frank Manners
  • Patent number: 4250436
    Abstract: A universal series motor having its brushes shifted at an angle against the direction of rotation is provided with a braking arrangement which removes power from the field windings and applies power directly to the armature winding.
    Type: Grant
    Filed: September 24, 1979
    Date of Patent: February 10, 1981
    Assignee: The Singer Company
    Inventor: Adrian Weissman
  • Patent number: 4189668
    Abstract: The invention provides snubbing apparatus for a D.C. motor in which a capacitor which is charged while the motor is rotating in a first direction is discharged into the gate of a thyristor to initiate the snubbing action. When the thyristor goes on a field coil is connected in series with the motor armature, so as to place the motor in a regenerative mode and snub the motor.
    Type: Grant
    Filed: January 19, 1978
    Date of Patent: February 19, 1980
    Assignee: Westinghouse-Bellambie (Proprietary) Limited
    Inventors: Derrick H. Willcock, Stanley Marcus, Ronald E. Hamm, David N. Bowden
  • Patent number: 4188569
    Abstract: A control circuit for an electric vehicle traction motor having separate armature and field windings, includes an armature winding current control, a braking contact which is in series with the armature winding and which is closed or opened in accordance with whether motoring or braking is required, an alternative path being provided for motor current during braking, reversing switch means connected in circuit with the field winding, a field current control and logic circuit means arranged to operate during a change for braking mode to motoring mode so as sequentially to reverse said reversing switch means when the field current is below a predetermined level, commence field current flow in the required direction for motoring and then close the brake contact whereby any residual magnetism in the field structure is reversed before the brake contact is closed.
    Type: Grant
    Filed: December 15, 1977
    Date of Patent: February 12, 1980
    Assignee: Lucas Industries Limited
    Inventor: Graeme R. Campbell
  • Patent number: 4144482
    Abstract: A brake circuit for a universal motor having an armature and a field winding normally connected in series therewith, the circuit including switch means operable to disconnect the power source and electrically connect the armature in series with the field winding and a brake resistor, with voltage limiting means in parallel with the field winding. The voltage limiting means include biasing diodes for maintaining the voltage across the field generally constant, resulting in a more even deceleration rate and a lower total brake time.
    Type: Grant
    Filed: April 7, 1977
    Date of Patent: March 13, 1979
    Assignee: Beckman Instruments, Inc.
    Inventor: Christopher M. Schwab
  • Patent number: 4132934
    Abstract: A control arrangement is described for dynamically braking a vehicle driven by an electric motor having a single field winding. The control arrangement comprises means for controlling the supply of power to the motor, a permanent magnet generator for mechanically coupling to the motor, and circuit closure means arranged to complete a circuit between the output of the generator and the field winding to dynamically brake the motor when the motor is de-energized by the controlling means.
    Type: Grant
    Filed: October 28, 1976
    Date of Patent: January 2, 1979
    Assignee: Cableform Limited
    Inventors: John Morton, Keith D. Stevens
  • Patent number: 4095153
    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.
    Type: Grant
    Filed: July 29, 1976
    Date of Patent: June 13, 1978
    Assignee: Westinghouse Electric Corp.
    Inventors: Thomas C. Matty, James H. Franz, Jr.
  • Patent number: 3995208
    Abstract: A control system for a d.c. motor, in which a cyclical d.c. drive signal is applied to the motor power input terminals as the system approaches balance. In each cycle, during at least part of the time interval between drive signal application to the motor terminals, a very low impedance (virtually a short circuit) is applied to the motor terminals. These braking pulses provide progressive braking as the motor approaches its balance point, limiting overshoot and ensuring a return without hunting from an overshoot condition to the balance point. As the system nears its deadband range, each braking pulse exceeds in duration the electrical time constant of the motor and constitutes a substantial portion of its associated cycle.
    Type: Grant
    Filed: April 25, 1975
    Date of Patent: November 30, 1976
    Inventor: Robert L. Parr
  • Patent number: 3984743
    Abstract: Regenerative braking controller for controlling a direct current motor adapted to drive a railway tramcar, an electric automobile or the like, comprises a direct current power supply, a series circuit composed of the armature and the field coil of the motor and a smoothing reactor, a chopper circuit connected in parallel with the series circuit and a diode inserted between the parallel circuit and the direct current power supply. The apparatus is characterized by an excitation circuit for exciting the field of coil of the d.c. motor with the voltage of the d.c. power supply so that a current may flow to the d.c. source due to voltage generated by the d.c. motor, and for supplying a power necessary for the operation of the chopper circuit from the d.c. source at the time of a low regenerating voltage of the d.c. motor.
    Type: Grant
    Filed: June 28, 1974
    Date of Patent: October 5, 1976
    Assignee: Hitachi, Ltd.
    Inventor: Taturo Horie