Abstract: A short-circuit protective device for a motor-driven and generator-driven electrical machine fed by a pulse-controlled a.c. converter has reverse-parallel circuitry that is switching dependent on a monitoring device. The monitoring device detects short circuits and is provided in a d.c. current supply line. Using the reverse-parallel circuitry and the monitor, an intermediate circuit capacitor of the pulse-controlled a.c. converter feeding the machine is isolated from the short circuit location.

Abstract: The subject invention is an electric motor brake which uses a simplified circuit enabling a timed injection of DC voltage into the motor windings of an induction motor. This DC voltage acts as a dynamic braking force and will bring the rotor, and whatever is connected to it, to a stop in a rapid fashion. An additional advantage of the invention is that it may be constructed and used as a stand alone device which may be attached to any electrical induction motor to achieve the desired braking effect. A further feature of the invention is the provision of a timing circuit that it is designed to be user adjusted to achieve the maximum possible effect rather than using a fixed design which would result in a compromise in order to be suited for wide usage.

Abstract: A D.C. solenoid control circuit for use in mechanisms driven by an A.C. motor. A rectifier converts A.C. current to D.C. current and provides an A.C. current flow path and a D.C. current flow path. Only the motor is connected in the A.C. current flow path to an output electrical power source. The D.C. solenoid is connected through the rectifier in the D.C. current flow path. The D.C. solenoid winding drives an actuator within the solenoid the activate the separate mechanism. In-rush current drawn by the motor upon start-up is converted to a high current level by the rectifier and input to the winding of the solenoid causing its immediate energization and, upon de-activation, its fast release.

Abstract: A capacitive breaking circuit for a single phase induction motor using a double throw power switch which in the off position, connects a series string, consisting of a charging rectifier diode, a current limiting resistor, a centrifugal switch and a braking capacitor, to the two power input terminals of a small single phase induction motor. With this circuit, while the motor is running, when the power switch of the motor is turned ON, DC current also charges the braking capacitor. When the power switch of the motor is turned to OFF, the braking capacitor discharges through the motor winding via the power switch to produce the braking function.

Abstract: In an AC motor drive, a voltage-source inverter is provided in the DC-link thereof with a GTO switching arrangement which upon braking allows matching the voltage, current domains for the forward power and regeneration modes, the GTO devices being interrupted with a duty cycle selected in response to the voltage difference between the inverter DC input voltage and a constant reference voltage.

Abstract: A current-type converter including a DC power source, a current-type converter, a load and a converter control unit, the converter control unit controlling so as to cause as least two states among a powering conduction state for supplying power from said DC power source to said load within predetermined control periods of both a powering control mode and a regenerative control mode, a regenerative conduction state for regenerating power supplied from the load toward the DC power source, and a reflux conduction state for short-circuiting the output of the current-type converter and returning the circuit current of the load, and the converter control unit varying the period length of respective states.

Abstract: An AC induction motor is energized by a voltage fed inverter coupled with a DC power source and is controlled in response to a torque request signal that is provided to accelerate or decelerate the motor as desired to maintain a desired torque output. The motor is operated to have each of a power and brake operation below the base speed of the motor and to have each of a power and brake operation above the base speed of the motor.

Abstract: A control device for supplying current to electrical appliances and particularly appliances having single phase capacitor start motors wherein the control device includes a changeover switch which is mounted between a source of power and the appliance motor and which changeover switch includes selectively operated components for controlling the power supply to the appliance motor or to terminate the power supply thereto. In one embodiment of the invention, a second circuit is provided intermediate the power source and the appliance motor for detecting the amount of current flowing in the circuits so as to insure connection of the starting capacitor of the motor, braking of the single phase motor when power is terminated and to provide an indication of overcurrent in the motor.

Abstract: A dynamic brake control system for an alternating current motor powered by a variable voltage, variable frequency inverter which regulates the speed of the motor. An AC to DC converter converts AC line power to DC power with the DC power being transferred to the inverter via a DC link. During electrical dynamic braking, the inverter functions to transfer power from the motor to the DC link. The torque available to the motor during braking is a function of the receptivity of the DC link. Link receptivity controlled by a resistance connected to the link in which the resistance is modulated at a frequency dependent upon the incoming AC line frequency at the converter. The modulation is binarily controlled so as to minimize ripple current on the DC link without the necessity of providing high frequency control of the modulating electronics.

Abstract: The invention relates to a method of and a device for braking an asynchronous motor by applying a direct current to the field windings thereof. According to the invention, an AC voltage appearing at the outer terminals (4,6) of two mutually series-connected field windings (1,2) of the asynchronous motor acting as a generator is rectified and connected to a coil (19) of a braking current relay (28) immediately after the operating current of the motor has been switched out, whereby said braking current relay (28) picks up and a terminal (R) of a braking current source (R, N) is connected by contacts (20,21,22) of said braking current relay (28) through a semi-conductor (24) to an outer terminal (6) of said field windings (1,2) and through another semi-conductor (25) to another outer terminal (4) of said field windings (1,2), a terminal (5) common to said field windings (1,2) being connected through a braking current adjuster (26) to another terminal (N) of the braking current source (R, N).

Abstract: An apparatus for controlling an A-C powered induction motor for an elevator cage, said apparatus comprising a rectifier for converting 3-phase A-C power into D-C electric power, an inverter connected to the rectifier for converting the D-C power into A-C power of variable voltage and variable frequency, a current detector connected to detect input current of the inverter, a power detector for detecting power supplied to the inverter based upon an output of the current detector, a control unit for generating a command signal to control the inverter in accordance with slip of the induction motor as determined by the power supplied to the inverter, and a correcting unit operable responsive to the power detected by the power detector for correcting the slip of the motor to maintain the power supplied to the inverter at predetermined values.

Abstract: In a pumping-up generator/motor system comprising an induction generator/motor, at least one cyclo-converter connected to the secondary winding of the induction generator motor for controlling the rotational speed of the generator/motor in the motor mode and for maintaining the output frequency thereof in the generator mode at a constant level, the center of the speed range of the generator/motor in the generator mode is set near the synchronous speed thereof and a plurality of converter units constituting each cyclo-converter are connected in parallel in the generator mode, and in series in the motor mode thereby allowing the capacity of the cyclo-converter to be made smaller.

Abstract: Three pairs of reversed polarity thyristors 20a,21a; 24a,25a; 28c,29c are connected directly between the three phases R, S, T of an AC power source and the corresponding phases of an elevator drive motor 5. The two pairs connected to the R and S phases implement upward driving, and the third pair connected to the T phase is used for both upward and downward driving but is held non-conductive during regenerative braking/deceleration when the motor operates in a two phase mode. Two additional thyristor pairs 22b,23b; 26b,27b which are used for downward driving are cross-connected between the R and S power source phases and two of the motor phases, to thus reverse the direction of motor rotation. Different individual thyristors in the pairs coupled to the R and S phases are selected in upward and downward deceleration modes. The overall circuit arrangement and firing selection/control scheme is designed to implement load sharing between the various thyristors and thus minimize duty cycle differences.

Abstract: An electric motor run and brake control circuit for controlling alternating current to a three-phase motor in which the circuit is operated by a single logic level input signal. When the input signal is low, a run relay is closed and AC power is applied to the motor. When the input signal goes high, the run relay is opened and the motor is braked for a fast stop. A brake capacitor and charge resistor limit both the time during which braking current is applied and the repetition rate of braking cycles.

Abstract: An AC induction motor brake control apparatus and method are provided for energizing the motor with an inverter supplied first voltage and an additional brake circuit supplied second voltage in phase with and additive to the first voltage as required to determine a desired brake torque above base speed operation.

Abstract: A constant voltage voltage-source inverter of a motor drive includes in its DC-link the combination of diode means, a GTO device and an auxiliary thyristor, the GTO device and the auxiliary thyristor upon transferring to the regenerating mode being cyclically controlled for conduction concurrently with the thyristor of the AC/DC converter so as to match the (voltage-current) domains converter and input of the inverter. Conduction of the GTO device is interrupted before each cyclical control thereof to allow recovery.Initiation of GTO and auxiliary thyristor conduction upon mode transfer is retarded to allow settling of the system before firing the thyristors of the AC/DC converter with a different firing angle.

Abstract: A current source inverter operates in a full current regenerative mode without the use of a tachometer, rather a constant volts-per-hertz loop is used in a motor feedback loop to generate a torque signal determining the current reference in a DC link current control loop, and the DC link voltage is sensed to derive a signal in magnitude and sign to allow maximizing current control under torque limits established on the basis of such sensed DC link voltage.

Abstract: The voltage in a converter 20 is compared with a reference voltage to detect an input power failure, in response to which a motor driven by the converter is automatically decelerated in accordance with a stored signal pattern/speed reduction curve such that the energy regenerated by the motor is equal to its power consumption. The DC bus voltage of the converter is thus maintained substantially constant during the regenerative braking of the motor, and it is promptly halted without resort to any mechanical braking unit.

Abstract: An inverter control apparatus contrived for improving the torque characteristic of an induction motor, wherein a current inputted to the induction motor is continuously detected, and the output voltage of the inverter is corrected by a voltage corresponding to a variation in the detected current.

Abstract: An AC motor drive includes a power converter which supplies current to a DC bus from three-phase power lines. An inverter drives the motor from power delivered to the DC bus and it regenerates power to the DC bus when the motor is decelerated. The power converter in turn regenerates the power to the power lines by controlling line current such that it is substantially in-phase with the applied line voltages. Current overload protection is provided for the transistor switches employed in the power converter bridge circuit.

Abstract: In a current type GTO inverter, commutation surge voltage is inevitably generated from an inductive load whenever each GTO is turned off. The commutation surge voltage thus generated is once stored in a capacitor (C.sub.1) through a diode surge voltage rectifier (5) and then restored to the DC source terminals (3A, 3B) of the GTO bridge-connected inverter (3) through a pair of other GTOs (G.sub.7, G.sub.8) turned on during steady state intervals of inverter commutation. Magnetic energy stored in a reactor (Lr.sub.1, Lr.sub.2) in motor-driving operation is recharged to the capacitor (C.sub.1) through the diode surge voltage rectifier (5) after the GTOs (G.sub.7, G.sub.8) have been turned off; the motor kinetic energy stored in the capacitor (C.sub.1) through diodes (D.sub.8, D.sub.9) in motor-braking operation is regenerated to the AC source side of the inverter (3) through a pair of other GTOs (G.sub.9, G.sub.10) when the voltage across the capacitor (C.sub.

Abstract: An apparatus for controlling an A-C powered elevator in which A-C electric power is converted into D-C electric power through a rectifier, the D-C electric power thus converted is converted into a A-C electric power of a variable frequency via an inverter, an A-C electric motor is driven by the thus converted A-C electric power, the A-C motor being controlled by a controller which is connected to a D-C control source, a cage is driven by the thus controlled electric motor, said motor producing regenerated electric power depending upon the operation condition of said cage, wherein provision is made of a regenerated electric power controlling device which is connected between the D-C side of the inverter and the controller in order to supply the regenerated electric power to the controller. When the voltage on the D-C side of the inverter becomes greater than a predetermined reference value, a switching element is rendered conductive, and the regenerated electric power is supplied to the controller.

Abstract: An electrotechnical regulating device for asynchronous rotating machines comprises capacitors in series with the windings of the asynchronous motor. In order to regulate the speed of rotation of an asynchronous motor, the device further comprises a variable-impedance short-circuiter connected in parallel between at least one of the windings and the associated capacitor or capacitors. The device serves to modify the torque of an asynchronous motor supplied at a variable frequency and at a fixed voltage, in order to control the speed of an asynchronous motor which is supplied at fixed or variable frequency or in order to regulate the voltage of an induction generator which rotates at a fixed or variable speed.

Abstract: An apparatus for processing the energy regenerated by an AC motor, which comprises a regeneration detection logic circuit (7) that produces a regeneration detection signal when the AC motor driving semiconductor switches are nonconductive and when the direction of the current flowing through the AC motor is opposite to that of the current when the AC motor is driven and a regeneration drive circuit 8 which drives the regenerated energy processing semiconductor switches responsive to the regeneration detection signal. The apparatus renders the regenerated energy processing semiconductor switches conductive so that the regenerated energy is returned to the AC power source only when the AC motor is in a regenerative condition. Therefore, electric power need be consumed in only small amounts by the resistors that protect the semiconductor switches for processing the regenerated energy, and the apparatus can be constructed so that it is small in size.

Abstract: The invention relates to a circuit for controllably driving an A.C. motor which includes a voltage supply with a pulse modulation regulator followed by an intermediate smoothing circuit and an inverse rectifier. Each phase of the inverse rectifier has two controllable load switching elements in series between two supply lines with each element being bridged by a recovery diode. The voltage of the intermediate circuit is adjustable by a desired value generator and the frequency of the inverse rectifier is adapted to follow the existing value of the voltage of the intermediate circuit. At least one phase of the inverse rectifier is associated with a braking circuit having a brake resistor between one phase connection and a brake connection which is disposed between two series connected brake switching elements disposed between the supply lines.

Abstract: An SCR bridge of an elevator speed control apparatus is connected between an induction motor 5 and two (R, S) of the three-phase power supply terminals. Two diagonally opposite legs of the bridge comprise single SCR's 25, 26, and the other two legs each comprise a pair of parallel, reverse polarity SCR's 21, 22; 23, 24. The third power supply terminal is connected directly to the motor through a single switch contact 8. By appropriately controlling the switch contact and the SCR.varies.s in accordance with the difference between the actual and commanded elevator speeds, the bridge can be configured to implement three phase running during acceleration and constant speed modes, single phase running during a transitional slow down mode, and D.C. braking during a deceleration mode.

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: A control circuit for driving an induction motor wherein an AC voltage is converted into a direct current by a rectifying circuit and the direct current is converted into a signal having a variable voltage and frequency by a transistor inverter connected in parallel with a smoothing capacitor, and a regenerative circuit is connected in parallel with the inverter, and a circuit is provided for comparing the terminal voltage V.sub.C of the smoothing capacitor and a reference voltage V.sub.r when braking is to take place is disclosed. When condition V.sub.C .gtoreq.V.sub.r exists, the transistor inverter is disabled but the regenerative circuit is allowed to operate; when the condition V.sub.C <V.sub.r exists, the transistor inverter is operated in the regenerative braking mode.

Abstract: A drive equipment has an AC motor and a self-commutated static converter for transmitting electrical power between the motor and a network for driving and braking the motor. The equipment has braking resistors, each of which is connected between a DC terminal and an AC terminal of the converter. Connected in series with each braking resistor is a thyristor which acts to control the current through the braking resistor.

Abstract: A method and apparatus for switching thyristor bridges in converting alternating current statically to direct current by the aid of two thyristor bridges connected in parallel so that a direct current machine consuming direct current will receive both positive and negative current. One and the same analog voltage controls both thyristor bridges so that when the controlling analog voltage is positive the first bridge is open and when the controlling analog voltage is negative the second bridge is open, and that as the circuit approaches zero-current state the bridges shift to a reciprocally oscillating mode of operation.

Abstract: A hybrid electrical braking method and system are provided for tool equipment having induction motor drives. This hybrid electrical braking can be used to advantage in various types of induction motor driven tool equipment where it is desirable rapidly to stop rotation of the motor rotor and tool, whenever the motor is turned off, for example in food processors of the type having a working bowl mounted on a base containing the induction motor, with tool drive means in the bowl for removably supporting a rotary food processing tool driven by the induction motor. The new electrical braking rapidly halts coasting of the rotor and tool by utilizing in sequence two different electromagnetic braking processes, producing rapid but gentle braking effect after the motor has been turned off.

Abstract: SCR devices replace the usual diodes of the rectifier bridge section of a wound-rotor slip-recovery system motor drive. By controlling the retardation angle of the SCR devices while controlling the line bridge for acceleration from zero speed to normal speed, the rating of the overall system is reduced. By removing the gating signal of the SCR's while operating at a retardation angle in the range between zero and 90.degree., operation is immediately brought to a stop in case of an emergency.

Abstract: SCR devices replace the usual diodes of the rectifier bridge section of a wound-rotor slip-recovery system motor drive, and by selection of the retardation angle of the SCR's between either zero or close to 180.degree., two-quadrant operation is made possible, which includes reverse torque and reverse rotation, while controlling the retardation angle of the power line bridge of SCR's.

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 controlled current inverter system forms the basis of an AC motor drive system for furnishing a motor load 22 with a variable frequency, variable magnitude AC current from a thyristor controlled DC to AC inverter 16 which is supplied current from a thyristor controlled AC to DC converter 10 by way of a DC link including an inductor 14. The frequency of the inverter is controlled by means of a control circuit including a voltage controlled oscillator 18. In the event that the converter 10 operates in such manner as to place a short circuit across the DC link 14 during a regenerative mode of operation of the motor 22, apparatus 36 is shown and described and a method is disclosed for providing a momentary advance gating of the inverter 16 which causes the motor 22 to shift from the existing regenerative mode toward a motoring mode and thereby quench any build-up of excessive converter-inverter circulating currents.

Abstract: An apparatus for controlling the operation of an AC motor wherein braking energy at the time of a reduction in motor speed is disposed of by regenerative braking. The apparatus includes a rectifier connected to the AC power source, a smoothing capacitor, a variable-voltage variable-frequency inverter, and a regenerative thyristor bridge circuit connected between the inverter and the rectifier through switching transistors. There is also provided a firing control circuit for controlling the firing of each thyristor in the thyristor bridge circuit and for controlling driving of the switching transistors in synchronism with the firing of the thyristors, the braking energy being fed back to the AC power source when the AC motor undergoes a reduction in speed. The apparatus is small and can be constructed simply and inexpensively.

Abstract: The braking of an a.c. motor is accomplished by sequence controlled outputs of a shift register circuit which sequentially disconnects the main a.c. electrical excitation from the a.c. motor, connects a full wave rectifier circuit to the a.c. motor and then applies the a.c. electrical excitation to the full wave rectifier circuit resulting in a braking current being supplied to the a.c. motor.

Abstract: A d.c. motor whose armature is supplied from an a.c. power source through an a.c./d.c. thyristor converter and is subject to damaging commutator flash-over, as from loss of a.c. voltage during regeneration is provided with a protective circuit which includes a normally charged capacitor and a diverter resistor which are connectable across the converter and motor armature, respectively, by SCR means in response to a fault condition such as either predetermined high output current from the converter (i.e., indicative of high armature current) or excess a.c. input current to the converter. Connection of the capacitor across the converter and its discharge instantaneously and forcibly but temporarily blocks current flow from the converter thyristors to the motor armature.

Abstract: Herein disclosed is a vibration interrupting device for use with a coin wrapping machine, in which coins are conveyed, while being counted, to a piling cylinder, in which this cylinder is vibrated by a vibrator so that the coins may be regularly piled in the cylinder, and in which a preset number of coins piled are carried to wrapping rollers by a coin receiving arm so that they may be wrapped. The vibration interrupting device includes a brake circuit which is operative to control the vibrator such that the vibrations to be applied to the piling cylinder are promptly interrupted by the time when the coin receiving arm is brought to receive the preset number of the coins piled in the cylinder. Thus, the coins piled can be prevented from being destroyed to pieces or getting scattered or lost when they are to be carried by the coin receiving arm.

Abstract: A safety device for preventing the automatic restart of a motor upon restoration of power to the motor. This device, in its preferred embodiment, includes a thyristor switch, such as a triac, in one of the power leads to the motor which is triggered by energizaton of the motor. Upon deenergizaton of the motor, the thyristor switch switches to its non-conductive state thereby preventing automatic restarting of the motor upon restoration of the power. A selectively actuable, momentary run switch is provided to momentarily shunt out the thyristor switch so as to selectively permit the restart of the motor.

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.

Abstract: For an automatic flue damper assembly of the type in which the motor of a clockwork mechanism is energized to hold the damper closed and the mechanism is mechanically biased to move the damper to an open position in the absence of motor energization, a stopping or braking arrangement is provided which applies DC to the motor for dynamic braking as the damper closely approaches its open position. Additionally, the remote possibility of a damper hang-up at an intermediate position resulting from a residual magnetic locking torque is substantially eliminated through the provision of an AC trickle circuit connected to the motor.

Abstract: A bidirectional triode thyristor is connected to an R phase of a three-phase induction motor through an up contact set and to its S phase through a down contact set. A full-wave rectifier bridge including four diodes is connected across the R and S phases to be enabled during deceleration of the motor. The thyristor is controlled by an R-to-S phase firing circuit responsive to a command acceleration signal during acceleration of the motor and a difference signal between a command deceleration signal and an actual speed signal for the motor during deceleration of the motor.

Abstract: The present invention is an induction motor control system which prevents an excessive induced voltage across the thyristors providing DC braking control. The amount of DC braking torque is controlled by the time of application of the DC braking voltage to the induction motor through a phase-control capacitor which sets the time of firing the braking thyristors within each half cycle of the AC voltage. In a first embodiment the firing of all the braking thyristors is inhibited upon application of the DC braking control signal until the half cycle of the AC voltage associated with a predetermined braking thyristor. In a second embodiment the firing of a predetermined braking thyristor is inhibited during the half cycle of the AC voltage of the application of the DC braking control signal and the next succeeding half cycle. In both embodiments the braking thyristors are fired during their associated half cycle of the AC voltage thereafter to apply a continuing DC braking voltage to the induction motor.

Abstract: There is disclosed a squirrel-cage motor for a winch drive or other application and control means for operating the motor in hoist or lower directions at any one of a plurality of speeds in either direction. The motor and winch are provided with a load brake. In one embodiment, the stator comprises two stator windings having different numbers of poles to provide high speed (fewer poles) and low speed (more poles) windings. The control means comprises a direct current power source, an alternating current power source, means for connecting the sources to the stator windings so that different speed points and braking operations are achieved, and means for operating the load brake. Low speed results from simultaneously energizing the low speed winding and the high speed winding from the alternating current power source and the direct current power source, respectively. Intermediate speed results from energizing only the low speed winding from the alternating current power source.

Abstract: An electrical apparatus producing pulsating high torque rotational vibration movement combined with a slow superimposed unidirectional rotary motion is disclosed. The apparatus includes an alternating current motor combined in a mechanically resonatable system with electrical apparatus producing a non-alterating component of magnetic flux in the motor structure. The torque generating ability of the motor is increased approximately five-fold even though the motor is operated from the same supply voltage. The disclosed apparatus is illustrated connected to a waste disposer device.