Abstract: An apparatus for controlling the power of an AC voltage supplying an electrical consumer (14) by phase control and for reducing harmonics caused by said phase control, particularly within a range of 4 kHz, preferably within a range of the third harmonic, comprising a first switching element (12) (TRIAC) connected in series with the consumer (14) and driven by a control device (20) for performing a phase control. A second switching element (34) connected in series with a resistor element (32) is provided in parallel to the first switching element (12). The control device (20) is adapted to drive the second switching element (34) shortly before the first switching element (12) into its conducting state for a short time period.

Abstract: A circuit for use with a power supply coupled in a switched leg of, for example, a lighting circuit, is described. The circuit provides a low impedance near the zero crossing of the AC signal and a high impedance thereafter, thereby allowing the power supply to draw current that bypasses, for instance, a light bulb.

Abstract: Apparatus operates at a power level within a range of power levels that includes a rated maximum power level of the apparatus. The apparatus includes circuit elements to deliver power at an output voltage to a load from a source at an input voltage using an inductor selectively connected between the source and the load during a power conversion cycle. The inductor conducts a current having an average positive value during the power conversion cycle. A first switching device is interposed between the source and a first terminal of the inductor. A second switching device is interposed between a second terminal of the inductor and the load. A switch controller turns ON the first switching device during a time interval within the power conversion cycle during which the current is negative.

Abstract: A method of power factor control for a power regulation system connected for supplying electric power to a reactive load, the power factor being characterized by a phase difference between a voltage waveform and an induced current waveform, the method comprising the steps of identifying a peak of an AC current waveform and a peak of an AC voltage peak waveform, determining a time delay between a designated peak of a half cycle of the voltage waveform and a peak of a corresponding half cycle of the current waveform; and adjusting the voltage applied to the load in a manner to vary the time delay so as to bring the power factor towards unity.

Abstract: A method with which the load current and thus the load moment of an asynchronous motor that is controlled via a phase-controlled two-phase thyristor power controller, can be easily influenced so as to allow a smooth starting operation. According to a first embodiment, the ignition point is determined in the controlled phase in order to adapt the flow angles of the subsequent current half waves. According to a second embodiment, the ignition point of the subsequent current half waves is brought forward in both controlled phases.

Abstract: The operating mode of a power modulation system is determined according to the nature of the load. The power modulation system can operate in either of two operating modes, namely a “reverse phase control” mode and a “forward phase control” mode. To this end, the load is supplied with power under predetermined low-load operating conditions by the power stage in the “reverse phase control” mode, overvoltages are detected and the power modulation system is caused to change to the “forward phase control” operating mode if an excessive number of overvoltages is detected.

Abstract: A method for operating an alternating-current (AC) controller system includes providing a first bi-directional switch coupled to a load and an AC power source. The first bi-directional switch is a solid-state device. The first switch is turned on in a first half-cycle of an AC cycle. The first switch is turned off in the first half-cycle of the AC cycle.

Abstract: A method and circuit for supplying a variable voltage to an electrical a.c. load (R, L), comprising: a control signal input for receiving a switching control signal to control load output voltage; first and second circuit output terminals (ACL1, ACL2) for connection to the load; first switch means (S1) having an input coupled to the control signal input and having an output coupled between one (ACL1) of the circuit output terminals (ACL1) and a first a.c. line terminal (AC1); second switch means (S2) having an input coupled to the first switch means and having an output coupled between the first and second circuit output terminals (ACL1, ACL2) and coupled to a second a.c. line terminal (AC2); and providing a switching control signal to the control signal input to switch the first and second switch means complementarily. The switch means may each comprise a power transistor (Q1; Q2) and a bridge rectifier (B1; B2).

Abstract: A method of providing a regulated AC output voltage at a predetermined level that makes use of an AC input voltage having a higher level, includes the steps of rectifying the input voltage to provide a DC input reference voltage, rectifying the output voltage to provide a DC output reference voltage, comparing the DC output reference voltage to the DC input reference voltage to provide a comparator signal, providing a triac circuit connected to the AC input voltage that supplies the AC output voltage and using the comparator signal to control the triac circuit.

Abstract: A bidirectional switch, including a first bidirectional switch between two power terminals of the switch, a low-voltage storage element between a first power terminal and a control terminal of the switch, and a control stage adapted to cause, upon each halfwave beginning of an A.C. supply voltage applied between the power terminals and when the switch is on, the charge of the storage element with a biasing depending on the sign of the halfwave.

Abstract: A system and method to parasitically take electrical power from a source of ac load power to provide a voltage source to directly power an associated control device is described. The system utilizes a controllable transconductance device to both selectively provide power to a controlled load and to develop a predetermined voltage to directly power the control device in a system where the ac load power is applied at one terminal and is passed through the transconductance device to be returned through the load. The system includes a means for establishing the predetermined voltage level to power the control device and for continuously monitoring that voltage level to maintain it as required, whether power is applied to the load or not. Alternative voltage regulators to provide isolated or non-isolated power to the control device irrespective of whether or not power is applied to the load are also described.

Abstract: A power modulation control system using PWM pulses is provided. The system comprises an AC voltage generator, an electric load, and a control circuit incorporating at least one rectifier. The electric load is connected between the generator and the rectifier, and first and second monodirectional switches are connected in parallel with the load.

Abstract: A circuit for loading the rectified AC voltage bus in a housekeeping power supply for an electronically controlled load is provided for avoiding large increases in the rectified AC bus voltage upon disconnecting the load. The load circuit includes a current sink, a relatively small energy storage capacitance, and a negative feedback circuit. The current sink includes a resistance coupled to the rectified AC voltage bus for sinking current whenever the semiconductor switch is on. When the semiconductor switch is off, the small capacitance discharges through the resistive voltage divider. When the voltage across the small capacitance decreases to a threshold mean AC rectified voltage bus value, then the negative feedback circuit provides sufficient current to turn the semiconductor switch back on and thus provide approximately the threshold mean AC rectified voltage bus value.

Abstract: An AC to DC power converter, comprising an input, an output, a plurality of pass elements connected in parallel between the input and output, and a controller for switching ON a subset of the plurality of pass elements. The controller sets an ON time for at least one pass element in the subset based on a load at the output and a phase angle of an input voltage at the input. The input voltage may comprise a single or multiphase signal. The number of pass elements in the subset is based on the load. In one embodiment, each pass element comprising a pair of series-connected field effect transistors coupled source to source and operated in fully enhanced mode.

Abstract: An alternating-current electric power controlling apparatus including a switch and a controller. The switch is configured to be turned on or off to connect or disconnect an alternating-current electric power source and an electric load. The controller is configured to control the switch to turn on or off to adjust supply of electric power from the alternating-current electric power source to the electric load. The switch is configured to be turned on or off when an electric power amplitude is substantially equal to 0.

Abstract: An apparatus for and method of inhibiting and overriding the normal operating mode of an input device connected to a communications network function within an electrical network made up of input devices, with a group of the input devices being capable of commanding an electrical control device to apply and remove electrical power from an electrical load. The input devices or nodes communicate with the electrical control device over the communications network. When one of the input devices is turned off, the normal operating mode of all of the other input sensors is inhibited. The electrical control device remains inhibited until all of the input devices are no longer in the off position. Thus, electrical power to the load controlled by the electrical control device remains disconnected until all input devices are in the on position. Local and remote signaling, control, and indication diagnostic and monitoring functions are also performed.

Abstract: The present invention relates to a bidirectional switching circuit including, in series, a bidirectional switching element controllable to be turned off and turned on, and a bidirectional conduction element forming a dipole and automatically selecting the conduction direction.

Abstract: An alternating-current electric power controlling apparatus including a switch and a controller. The switch is configured to be turned on or off to connect or disconnect an alternating-current electric power source and an electric load. The controller is configured to control the switch to turn on or off to adjust supply of electric power from the alternating-current electric power source to the electric load. The switch is configured to be turned on or off when an electric power amplitude is substantially equal to 0.

Abstract: The present invention relates to a power dimmer of a load, powered by an a.c. voltage, of the type including a bidirectional switch associated in series with the load, the switch being normally closed and controllable to be opened upon each halfwave of the a.c. voltage.

Abstract: An output voltage of a rectification smoothing circuit is compared with a reference voltage. When a reduction in the output has been detected, an A/D converting circuit converts a result of the comparison which is negatively fed back by an output voltage feedback circuit to obtain a control signal for a bidirectional switch element inserted into a primary side of a transformer so as to turn ON or OFF synchronously or asynchronously with a commercial power supply via an intermittent control circuit.

Abstract: An AC voltage regulator, which not only has a fast response speed with respect to input voltage fluctuations but also is small in size and light in weight and is capable to boost an input voltage, comprises a high-frequency transformer 4, a first bi-directional semiconductor switch circuit 3, a second bi-directional semiconductor switch circuit 5 and a third bi-directional semiconductor switch circuit 6; an input AC voltage is ring-modulated by the first bi-directional semiconductor switch circuit 3 and the obtained ring-modulated voltage is transformed at a high frequency by the high-frequency transformer 4 and then demodulated by the second bi-directional semiconductor switch circuit 5, and the obtained AC demodulated voltage is added to the input AC voltage to produce an AC raised voltage, and the AC raised voltage is pulse width modulated by the third bi-directional semiconductor switch circuit 6, which is controlled to become ON only while the second bi-directional semiconductor switch circuit 5 is OFF,

Abstract: A circuit is provided for supplying a load from an AC voltage supply. The circuit includes a control circuit and a bidirectional switch coupled in series with the load. The bidirectional switch includes two one-way switches connected in antiparallel, and the control circuit controls the bidirectional switch based on a relatively low DC voltage. The bidirectional switch is connected to a first terminal of the AC voltage supply, and the DC voltage is referenced to the first terminal of the AC voltage supply. Additionally, an apparatus connected to an AC voltage supply and a relatively low DC voltage is provided. The apparatus includes a control circuit, a load to be supplied by the AC voltage supply, and a bidirectional switch coupled in series with the load. The bidirectional switch includes two one-way switches connected in antiparallel, and the control circuit controls the bidirectional switch based on the DC voltage.

Abstract: A switching power supply system is disclosed for powering electrical equipment while minimizing disturbance to an AC power line source. The system includes first and second AC switches which are operated at alternate intervals with respect to each other to permit current to flow between the AC power line source and the load over intervals of the AC voltage cycle. An energy storage element is included in an output filter and stores energy during intervals of the AC voltage cycle and releases the stored energy during the alternate intervals of the AC voltage cycle. By the disclosed switching power supply, the voltage applied to the load and the current flow between the source and the load are sinusoidal, have minimal energy in frequencies other than the fundamental AC power line frequency, have minimal harmonic distortion, result in a power factor close to unity, and are steady and non fluctuating.

Abstract: For use in a power system having a power train, a rectifier having an input and an output and a method of controlling the rectifier. The rectifier comprises: (1) switching circuitry coupled between the input and the output, the switching, circuitry adapted to operate in selected one of (a) a bidirectional mode of operation and (b) an unidirectional mode of operation to rectify substantially alternating current at the input to produce substantially direct current at the output; and (2) control circuitry coupled to a control input of the switching circuitry, the control circuitry capable of sensing a characteristic of the power system and transitioning the switching circuitry between the bidirectional mode and the unidirectional mode as a function of the characteristic thereby to prevent substantial reverse power flow through the rectifier.

Abstract: A thyristor-based forward phase control (FPC) system for controlling the power delivered to a load from an AC power source employs a short-circuit test cycle to protect the thyristor from damage. Upon activation of the FPC system, the thyristor is triggered at a phase less than one-twelfth cycle before a zero crossing so that, if there is a short, the resulting peak current will be insufficient to damage the thyristor but will exceed a predetermined threshold current corresponding to a repetitive overload current. If during the test cycle, the threshold current value is crossed, the FPC system does not trigger the thyristor again and does indicate that a short exists. The threshold current value is selected to correspond to the thyristor's steady-state load rating. If it is exceeded during normal (including warm-up and request-based) operation, steps can be taken to address an overload condition.

Abstract: An apparatus for and method of inhibiting and overriding the normal operating mode of one or more input devices connected to a communications network. The present invention functions within an electrical network made up of a plurality of input devices wherein a group of input devices is capable of commanding an electrical control device to apply and remove electrical power from an electrical load connected thereto. The input devices or nodes communicate with the electrical control device over a communications network. When one of the input devices is turned off, the normal operating mode of all the other input sensors is inhibited. The electrical control device remains inhibited until all the input devices are no longer in the off position. Thus, electrical power to the load controlled by the electrical control device remains disconnected until all input devices are in the on position. Local and remote signaling, control and indication diagnostic and monitoring functions are also provided.

Abstract: The power conversion system of this invention achieves precisely regulated input current and precisely regulated output voltage in a two step process whereby one power converter sub-system (141) provides input current regulation and a second power converter sub-system (158) provides output voltage regulation. The two converter sub-systems are arranged so that the second power converter sub-system (158) is powered by the first power converter sub-system (141) and the output of the second power converter sub-system (158) is placed in series with an output of the first power converter sub-system (141) to form the system output so that the load voltage is the sum of the two outputs placed in series. With this arrangement only a small fraction of the load power needs to be processed by the second power converter sub-system (158) which yields higher system efficiency and smaller system size, weight, and cost.

Abstract: An improved trigger circuitry for a high side thyristor application having a thyristor connected to an A/C line, a capacitor connected across the A/C line to A/C neutral through impedance, an electronic switch connected from the thyristor to the junction of the capacitor and associate impedance. During the positive portion of the A/C cycle, the thyristor is triggered in quadrant III via the switch and the capacitor is charged. During the negative portion of the A/C cycle, the discharge of the capacitor triggers quadrant II of the thyristor via the switch.

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provide substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25 percent in lighting loads while producing minimal reduction in light output. The system utilizes a Triac and parallel capacitor bank in series with the load. The Triac is turned on in response to a near-zero differential voltage measured across the Triac and is turned off near the peak of each AC half cycle by shunting current around the Triac. The capacitor absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of Triac turn-off. This energy, in turn, provides longer on-period for the lamp, thereby permitting more light and increased operating efficiency.

Abstract: For use in a power system having a power train, a rectifier having an input and an output and a method of controlling the rectifier. The rectifier comprises: (1) switching circuitry coupled between the input and the output, the switching circuitry adapted to operate in selected one of (a) a bidirectional mode of operation and (b) an unidirectional mode of operation to rectify substantially alternating current at the input to produce substantially direct current at the output; and (2) control circuitry coupled to a control input of the switching circuitry, the control circuitry capable of sensing a characteristic of the power system and transitions the switching circuitry between the bidirectional mode and the unidirectional mode as a function of the characteristic thereby to prevent substantial reverse power flow through the rectifier.

Abstract: An AC voltage regulator provides a desired AC voltage to a load. The desired AC voltage is within a predetermined range above and below that of an AC voltage source. The AC voltage regulator has a transformer, the secondary winding of which is configured to be placed in series with the AC voltage source and the load. A plurality of switches is configured to direct current from the AC voltage source through the primary winding of the transformer. The switches are further configured to control the direction in which current flows through the primary winding of the transformer. A pulse width modulator controls the switches according to a desired cycle period.

Abstract: The control circuit includes: a series circuit of a first triac and a reactor; and a second triac in parallel with this series circuit so as to perform control of activation of a fixing heater. Since the fixing heater has a low resistance when the power switch is first turned on, the first triac is operated to perform phase angle control of current flow, and when the phase angle has become approximately equal to 180.degree., the first triac is stopped, at the same time the second triac starts to be operated. The switching from the first triac to the second triac is made quickly so that it is possible to reduce the power consumption from the reactor.

Abstract: For use in a power system having a power train, a rectifier having an input and an output and a method of controlling the rectifier. The rectifier comprises: (1) switching circuitry coupled between the input and the output, the switching circuitry adapted to operate in selected one of (a) a bidirectional mode of operation and (b) an unidirectional mode of operation to rectify substantially alternating current at the input to produce substantially direct current at the output; and (2) control circuitry coupled to a control input of the switching circuitry, the control circuitry capable of sensing a characteristic of the power system and transitioning the switching circuitry between the bidirectional mode and the unidirectional mode as a function of the characteristic thereby to prevent substantial reverse power flow through the rectifier.

Abstract: A rectifier circuit in a three-phase bridge connection includes four-segment main switches. Resonance capacitors are each connected in parallel with a respective one of the main switches. An auxiliary commutation device is connected between two DC terminals. The auxiliary commutation device has an auxiliary four-segment switch and a resonance inductor connected in series therewith.

Abstract: A system for controlling an Alternating Current (AC) signal to an AC powered device. The system uses a microcontroller to monitor the cycles of the AC signal supplied to the AC powered device. By utilizing cycle counting, the microcontroller can supply various numbers of waveforms to the AC powered device in order to adjust the speed and/or energy supply level to the AC powered device. At full power, all the cycles of the AC signal are provided to the AC powered device. If the speed and/or energy supply level of the AC powered device needs to be reduced by half, the microcontroller supplies every other cycle of the AC signal to the AC powered device.

Abstract: A method for changing the inductance of a multiple-tap transformer in a circuit having a current regulator and the transformer, including the steps of comparing the current regulator's duty-cycle to a duty-cycle setpoint, increasing the turns ratio of the transformer when the duty-cycle is less than the setpoint. An apparatus for switching the taps of a multiple-tap transformer connected to a power supply and a load circuit, including a load regulator for generating a desired duty-cycle signal, and an inductance controller having a first reference signal generator, a comparator for comparing the reference signal to the desired duty-cycle, and relays connected to the transformer taps that are responsive to the comparator.

Abstract: A regulating switch circuit for conditioning operation of a first load upon operation of a second load wherein the first load and the second load consume electrical energy from a power source includes a detecting means for detecting the operation of the second load and a sensing means for sensing an amount a parameter of the electrical energy supplied to at least one of the first and second loads exceeds a predetermined level. A load control device couples at least one of the first and second loads to the power source wherein the load control device has a control terminal. A control circuit is coupled to the control terminal of the load control device and is responsive to the sensing means and the detecting means to variably adjust the electrical energy supplied by the power source to at least one of the first and second loads to limit the parameter of the electrical energy to the predetermined level.

Abstract: Instabilities in the output voltage provided from an AC power supply system such as an uninterruptible power supply connected to a power factor correcting load are suppressed by a dynamic voltage regulation stabilizer system which is connected across the output lines from the power supply system to the load. The DVR stabilizer system includes a rectifier connected to the power supply system output lines. A capacitor is connected across the output nodes of the rectifier. Switching devices form a bridge that connects the capacitor to the output lines. Selected switching devices in the bridge are turned on for a selected duration encompassing the time of the peak of each half-cycle of the AC voltage waveform provided by the power supply system. During normal operation, where the peak AC voltage from the power supply system is substantially constant, the capacitor charges up through the rectifier to a voltage level near the peak value of the AC voltage waveform.

Abstract: A power controller (10) for supplying power to a power distribution network (N) in which power from a polyphase source (G) is routed to using equipment (E) connected to the network through the power controller. A plurality of solid-state power devices (82) switch each separate phase of the polyphase power to the equipment. A firing circuit (14) controls gating of the switches to route the power. Fuses (F) are connected between the switches and the using equipment to interrupt power flow to the equipment if excessive current begins to be drawn. A con, roller (20) controls a shutdown sequence employed by the controller to eliminate current spiking at shutdown. The various components are housed in an enclosure (22) which includes a mounting structure (56) for mounting the aforesaid components. A cooling system (26) employs a fan (88) for directing air flow through the mounting structure to cool the components.

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provide substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25 percent in lighting loads while producing minimal reduction in light output. The system utilizes a Triac (32) and parallel capacitor bank (58) with the load (22). The Triac (32) is turned on in response to a near-zero differential voltage measured across the Triac (32) and is turned off near the peak of each AC half cycle by shunting current around the Triac (32). The capacitor (60) absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of Triac turn-off.

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provides substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25% in lighting loads while producing minimal reduction in light output. The system utilizes a triac and parallel capacitor bank in series with the load. The triac is turned-on in response to a near-zero differential voltage measured across the Triac and is turned-off near the peak of each AC half cycle by shunting current around the Triac. The capacitor absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of triac turn-off. This energy in turn provides longer on period for the lamp, thereby permitting more light and increased operating efficiency.

Abstract: A circuit is provided for obtaining precise lamp voltage control and for compensating for varying or fluctuating input from an AC voltage source. The lamp is switched on by a switching device such as a triac. When the triac is powered, a simultaneous powering occurs of a second switching device such as an SCR. The SCR produces a scaled down RMS voltage output which closely matches the actual RMS lamp voltage. This second simulated voltage is precisely controlled in a feedback circuit which includes an RMS to DC converter and a feedback controller. The controller compares a converted DC voltage with a reference voltage and generates a firing pulse to the triac which is advanced or delayed so as to compensate for variations in the AC source as manifested by variations in the converted DC signal relative to the reference signal.

Abstract: A power controller (10) and a method for supplying power to a power distribution network (N) in which power from a polyphase source (G) is routed to using equipment (E) connected to the network through the power controller. A plurality of solid-state power devices (82) switch each separate phase of the polyphase power to the equipment. A firing circuit (14) controls gating of the switches to route the power. Fuses (F) are connected between the switches and the using equipment to interrupt power flow to the equipment if excessive current begins to be drawn. Circuit breakers (74) are connected between the power source and the switches to interrupt current flow to the equipment if excessive current is drawn. A control unit (20) controls operation of the controller. The firing circuit includes a master firing unit (164a) and a slave firing unit (164b).

Abstract: A control system is provided for controlling the average power from an alternating voltage source (AC) to a load having inductive properties. The system uses a synchronous switch shunted by a capacitor connected between the source (generator) and sink (load) to pulse duration modulate the AC voltage carrier wave. A control signal generator circuit drives the synchronous switch such that the switch is closed at a variable time early in each half-wave of the AC voltage source carrier wave and such that the switch is opened at a subsequent later, variable time during that half-wave. This is accomplished by sensing the voltage across the synchronous switch in order to inhibit closing of the switch early in the half-wave until the synchronous switch voltage (and thus the voltage on the capacitor) is substantially zero and then opening the synchronous switch at a point in time to give the desired volt-second area between closure and opening within each half-wave.

Abstract: A light dimmer with semiconductor power devices coupled between an alternating current supply and a lamp load, in the course of varying average power supplied to the lamp load, transitions the power devices under load between one and the other of substantially conductive and non-conductive conditions, increasing the duration of the transition by the power device itself from the minimum possible duration to reduce generated EMI. Undesirable effects of the high current demands of cold lamp filaments are reduced by initially increasing the conductive portion of half-cycles, relative to the proportion required to produce the desired amount of average power, while avoiding transitions at phase angles that would produce excessive losses. A transition shape may be employed in this mode and in normal operation that maximizes audible lamp noise suppression for a given level of thermal losses.

Abstract: The present invention provides a electronic switch suitable for fading on/off control of electrical equipment like lamps and motors. The main circuit comprises a rectifier bridge circuit and a thyristor. A control circuit includes a fast discharging synchronic integrator and a trigger pulse integrator, the former acts as a pulse phase shifter to provide a self-adapting magnitude variable sawtooth waveform, while the latter acts as a dynamic phase variation memory so as to provide a variable reference for comparison. Trigger pulses which are feed back via the main circuit causes the synchronic integrator to fast discharge. If a control switch is closed, the voltage on the integral capacitor and the trigger angle decreases gradually to produce the fade on. In the fade off process, the conditions are just the opposite. Fading on/off time can be independently set.

Abstract: An output module which is used in a factory automation control apparatus is disclosed. The output module is connectable to both of AC and DC power sources, which is constituted by a control element controlled by the output signal in the factory automation control apparatus, and a drive element being bi-directionally conducted by the signal of the factory automation control apparatus. A first embodiment uses a full wave rectifier to rectify the current from/to the load, and a second embodiment uses two opposite channel type transistors to respectively conduct during different polarities.

Abstract: A solid state circuit interruption arrangement monitors a current path to provide protection to both a load and a solid state switch. The arrangement includes an energy absorber for absorbing energy from the current path in response to the solid state switch interrupting the current path, and a control circuit for periodically generating the interrupt signal to interrupt the current path for prescribed intervals and to control the current supplied to the load between a maximum current level and a minimum current level.

Abstract: A full-bridge transistor inverter is connected at its DC supply-side with an energy-storing capacitor. The inverter's output terminals are connected in series between a source of AC voltage and a load; which load may be an electric motor, a fluorescent lighting system, etc. By controllably switching the transistors of the inverter ON and OFF at some rate higher than, but basically synchronous with, the frequency of the AC voltage, effective control of the flow of power between the AC source and the load is achieved. DC voltage on the energy-storing capacitor is obtained from the AC source and established by way of the timing of the switching action of the inverter.

Abstract: A load is supplied by a transformer supplied via a voltage regulator and thyristor network. The thyristor network and regulator are simultaneously controlled to respond to changes in the load and in practice the thryistors respond rapidly and are re-adjusted as the regulator is inherently more slowly adjusted. The result is that the thyristors produce minimum reflected harmonics overall in the mains and an optimum power factor can be achieved for each power setting.