Abstract: Described is a power connector device for separating an electrical connection under direct current (DC) voltage or alternating current (AC) voltage between an electrical connector element and an electrical contact element. The power connector device includes the electrical contact element. The electrical contact element has a first conductive part and a second conductive part spaced apart one from the other so as not to be directly electrically conductively connected to one another. The power connector device includes a semiconductor switch for maintaining an electrical connection between the electrical connector element and the electrical contact element during separation of contact between said electrical connector element and said first conductive part to thereby prevent arcing during electrical disengagement of the electrical connector element from the electrical contact element.

Abstract: A system and method for detecting energetic particles include a detector onto which the particles are impinged. An output signal from the detector, indicative of the energy of the particles, is directed by an AC-coupler to a measurement device to determine particle characteristics such as mass and/or abundance. The detector is selectively couplable to positive or negative bias voltages, and in one embodiment is differentially biased to eliminate ringing due common-mode excitation. The AC-coupler has capacitively-coupled input and output terminals that are embedded in a transmission line structure including capacitances that in some embodiments serve as the sole energy storage component in order to reduce the effects of parasitic inductance found in conventional detection circuits. In some embodiments, a pulse compensation network is provided, to reduce undershoot and ringing due to remote installation of the AC-coupler caused by reflection of low frequency components blocked by the AC-coupler.

Abstract: A semi-controllable device driving method and apparatus and a hybrid device of the present disclosure belong to the electrical field, and are particularly a driving method, with no driving dead zone or with an extremely small driving dead zone, that is applicable to a semi-controllable device such as a thyristor; a semi-controllable driving apparatus, with no conduction dead zone or with an extremely small conduction dead zone, that is applicable to a driving loop of a semi-controllable device such as a thyristor; and a hybrid device with no conduction dead zone or with an extremely small conduction dead zone.

Abstract: A load control device for controlling the power delivered from an AC power source to an electrical load includes a thyristor, a first current path for conducting current through a gate terminal of the thyristor, and a control circuit for controlling the first current path to conduct a pulse of current through the gate terminal to render the thyristor conductive at a firing time during a half cycle. The first current path is able to conduct at least one other pulse of current through the gate terminal again after the firing time until, a transition time before the end of the half-cycle, but prevented from conducting pulses of current after the transition time until the end of the half-cycle. The load control device may comprise a second current path for conducting current through the electrical load between the transition time and the end of the half-cycle.

Abstract: An electric power conversion device comprises a conversion circuit having bi-directionally switchable plural pairs of switching elements connected to respective phases and converting an inputted AC power into an AC electric power. A first switching time is calculated using detected voltages detected by voltage sensors and an output command value. A second switching time is calculated using a carrier and the calculated first switching time. The second switching time is such that, in one period of the alternating current electric power outputted from the conversion circuit, the second switching time included in a first half period of the one period is equal to the second switching time included in a second half period of the one period.

Abstract: An electric power conversion device comprises a conversion circuit having bi-directionally switchable plural pairs of switching elements connected to respective phases and converting an inputted AC power into an AC electric power. A first switching time is calculated using detected voltages detected by voltage sensors and an output command value. A second switching time is calculated in a form of a time which is a subtraction of the first switching time from a half period of a carrier and, using this time, control signals to switch on and off of the switching elements are generated.

Abstract: A current correction circuit (200) has an input (201) and includes: a first controllable current source (220) having an input connected to the circuit input for drawing a first current (I 220) from the circuit input; a differentiator (210) having an input coupled to the circuit input and having an output coupled to the first current source; and/or a second controllable current source (240) having an input connected to the circuit input for drawing a second current (I 240) from the circuit input; a voltage comparator (230) having a first input coupled to the circuit input (201), having a second input coupled to receive a reference signal (Vref), and having an output coupled to the second current source. The circuit is responsive to voltage changes by drawing first current pulses (221) from the circuit input, and/or to low voltages by drawing second current pulses (241) from the circuit input.

Abstract: An electronic control system for operating lighting is rated and operable from normal AC mains supply voltages. A street light controller is adapted to activate a luminaire when ambient light levels are considered too dark and, conversely, when ambient light levels are sufficient, the luminaire is turned off.

Abstract: The invention relates to an electrical power tool, particularly an electric hand power tool, for operating with alternating current, having an electric motor, and electronic control device, and an electrical power switch for actuating the electric motor, wherein the electronic control device comprises a bias voltage output and a detection input, connected to each other by means of a voltage divider comprising a summation point and to the side of the power switch facing the electric motor, and the control device is further designed such that the potential at the detection input is monitored after actuating the power switch and used for checking whether the power switch is conducting, and that it is actuated again if the power switch was not conducting or returned to the non-conducting state during the monitoring, and that said checking and any renewed actuation of the power switch is repeated within a half-wave of the alternating voltage.

Abstract: The present invention is directed to an intelligent dimmer that is capable of “learning” the type of load it is controlling, and adjusts its operating parameters accordingly. The present invention can adaptively drive electrical loads over a wide range of wattages. The intelligent dimmer of the present invention is configured to automatically calibrate itself based on the load current demands of a particular electrical load. The intelligent dimmer of the present invention also adaptively limits in-rush currents to extend the life expectancy of the solid state switching components used therein.

Abstract: An electronic device for inductive load switching is described. The electronic device includes a voltage sensor module that monitors a voltage waveform. The electronic device also includes a current sensor module that monitors a current waveform. The electronic device additionally includes a computing module coupled to the voltage sensor module and to the current sensor module that determines a power factor based on the voltage waveform and the current waveform. The electronic device further includes a controller module coupled to the computing module that switches off an inductive load based on the power factor. The electronic device has dimensions for fitting within a wall box.

Abstract: A power detection regulation device including a power detection signal generator, a power state detector and a regulated output unit is disclosed. The power detection signal generator receives the input power from an external power supply and generates a power detection signal. The power state detector generates a power state signal based on the power state derived from the power detection signal. The regulated output unit receives the power state signal and generates a driving signal to an external electrical device in accordance with the feedback signal from the external electrical device. The power state signal is provided for the external electrical element to perform relevant processes, and the regulated output device can output the predetermined driving signal on receiving the power state signal indicating some abnormal situation in the input power so as to maintain the normal operation performed by the actuating element in the external electrical device.

Abstract: Among many embodiments, a power conversion apparatus and a method for converting power are disclosed. The power conversion apparatus may include switching components configured to create an alternating current; a preemptive detector arranged and configured to provide, in advance of the alternating current reaching a zero-crossing, a control signal responsive to the alternating electrical current approaching the zero-crossing; and a controller configured, at least in part, to change a state of the switching components before the zero crossing, in response to the control signal.

Abstract: A microprocessor operated controller device and associated method for modifying an AC input power to provide a reduced power AC output power to a load when coupled to the controller device. The AC output power has a series of cut-out pulses in each half cycle of the AC output power waveform. The device includes a switching system having a plurality of switching elements for positioning the series of cut-out pulses in each half cycle of a waveform of the AC input power to result in said reduced power AC output power and a switch control system for coordinating opening and closing of the plurality of switching elements during positioning of the series of cut-out pulses. The switch control system includes a synchronization system for synchronizing the switching system with timing of each half cycle of the AC input power waveform.

Abstract: A control system (300) allows recognized standard premise electrical outlets, for example NEMA, CEE and BS, among others to be remotely monitored and/or controlled, for example, to intelligently execute blackouts or brownouts or to otherwise remotely control electrical devices. The system (300) includes a number of smart receptacles (302) that communicate with a local controller (304), e.g., via power lines using the TCP/IP protocol. The local controller (304), in turn, communicates with a remote controller (308) via the internet.

Abstract: A processor includes analog signal input ports, an A/D conversion unit, and an ALU in a stage subsequent to the A/D conversion unit, separately from a CPU. The ALU not only stores a comparison result in a RAM independently of the CPU, but also compares an output value of the A/D conversion unit with a reference value set in the RAM, and interrupts the CPU or issues a command to a PWM generator in accordance with a flag based on the comparison result. This realizes high-speed processing in accordance with a change in an analog signal, although the processor has a low cost and a low clock frequency overall.

Abstract: The invention relates to a circuit layout for controlling at least one heating element, in particular a heating element for an electric cooking and/or baking device, with at least one electric temperature sensor for measuring the temperature of the heating element and/or a surface heated by said heating element and with safety electronics for automatic shut-off of the heating element when the temperature measured by the at least one sensor reaches and/or exceeds a temperature threshold value (TS).

Abstract: A zero current detector for a DC-DC converter includes a first transistor having a drain, a gate, and a source for sensing the voltage of a first terminal of a power transistor; a second transistor having a drain, a gate, and a source for sensing the voltage of a second terminal of a power transistor; and a third transistor having a coupled gate and drain for receiving a reference current that is coupled to the gates of the first and second transistors and a source coupled to the source of the first transistor, wherein an output signal is provided by the drains of the first and second transistors. A load is coupled to the drains of the first and second transistors. The zero current detector also includes a fourth transistor having a current path coupled between the source of the second transistor and the second terminal of the power transistor and a gate for receiving a control signal.

Abstract: The improved single stage power converter circuit topology substantially reduces EMI that is conducted to the AC line, reduces input AC current inrush, improves output ripples by the use of an auxiliary supply near zero crossings of the line AC voltage, provides Power Factors greater than 0.95, provides Total Harmonic Distortions less than 15%, and maintains constant power, including constant power in a non-linear output load. Further, this circuit topology provides output open and short circuit protections by reducing current stress in power components. This topology can also make the power source to appear as a fast-acting variable impedance source, an ideal source for powering an output load that has negative resistance characteristics such as gas discharge lamps.

Abstract: In-home communication systems 110 and 130 and an access communication system 120 that are capable of co-existing. The communication systems 110 and 130 and the access communication system 120 are able to co-exist by utilizing TDM that is in synchronization with a power cycle. Further, communication system that needs to secure AV-QoS assigns transmission timing to a slave station within itself by synchronizing a beacon cycle with a cycle of a power line.

Abstract: For the purpose of providing a resonant switching power supply device having a wide output voltage variable range by changing its switching frequency, the resonance circuit thereof comprises a switching transformer, a first resonance section connected in series with the switching transformer, and a second resonance section connected in parallel with the switching transformer, wherein the resonance frequency characteristic in the case that the DC load current is large is formed using the series-connected devices of the first resonance section, and the resonance frequency characteristic in the case that the DC load current is small is formed using the first resonance section, the second resonance capacitor of the second resonance section and the switching transformer.

Abstract: A device and method are provided for detecting and configuring a solid state dimmer when wired in series or parallel with a load powered by an alternating current (AC) input. The device can comprise a microcontroller configured to be powered by the AC input. A zero-cross detector in communication with the microcontroller is capable of detecting when an AC waveform crosses zero and generating a corresponding pulse signal when the AC waveform crosses zero. A pulse analyzer can be included and configured to determine when the zero-cross detector is generating pulses exceeding a pre-determined time length threshold that represents a serial wiring configuration.

Abstract: A phase detecting device includes a power input unit that receives an AC voltage; a phase detector that detects zero-crossing points of the AC voltage, and outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected; and a power switch that selectively cuts off a flow of AC into the power input unit in response to a mode control signal.

Abstract: A voltage regulator includes a load control unit having an output configured to be coupled to a load. The load control unit is configured to be responsive to a load control signal for controlling the delivery of power to the load. A voltage regulator further includes a feedback unit coupled to the output of the load control unit. The feedback unit is configured to produce a feedback signal indicative of a voltage level applied to the load at the load control unit output. A voltage regulator still further includes a controller responsive to the feedback signal that is configured to generate the load control signal such that the voltage applied to the load substantially corresponds to a predetermined reference voltage level.

Abstract: Timing of zero voltage in zero-voltage detector for detecting zero voltage of a commercial power supply 1 is predicted and input from the zero-voltage detector 6 is received only for a given time before and after the predicted timing, whereby overvoltage and overcurrent caused by a zero point shift can be prevented. Thus, it is provided a magnetron drive power supply which is excellent in stability for change in the power supply environment such as noise or instantaneous power interruption.

Abstract: An apparatus (14) for detecting a zero-crossing of an alternating current after occurrence of a fault in a current path (2) for determining a suitable time for opening an electric switching device (2) arranged in the current path for breaking the current in the current path comprises members (15) adapted to detect the current in the current path. An arrangement (19) is adapted to calculate the dc-level of the current and the decay of the dc-level with time on the basis of values of the alternating current detected and also predict the time for a future zero-crossing of the alternating current on the basis of at least current values obtained through said current detection, the dc-level calculated, the dc-decay calculated and information about the period time of the alternating current.

Abstract: In one embodiment of the present invention, a power controller for an AC load comprises: a user interface adapted to interact with a user to produce at least one user interface signal; and a control module adapted to electrically couple a line voltage supply, electrically couple the AC load, and provide electrical power to the AC load as a function of the at least one user interface signal by implementing a low-flicker, cycle-skipping control algorithm, the control algorithm comprising a plurality of cycle patterns, the cycle patterns comprising a plurality of main power levels.

Abstract: Timing of zero voltage in zero-voltage detector for detecting zero voltage of a commercial power supply 1 is predicted and input from the zero-voltage detector 6 is received only for a given time before and after the predicted timing, whereby overvoltage and overcurrent caused by a zero point shift can be prevented. Thus, it is provided a magnetron drive power supply which is excellent in stability for change in the power supply environment such as noise or instantaneous power interruption.

Abstract: A junction box (10) is constituted by a junction box body (14), on which a fuse outlet (11e) is formed, and a casing (18) for housing the junction box body (14). The casing (18) is formed by a lower case (17) for housing the junction box body (14), and an upper case (16) for detachably covering a housing hole (17i) of the lower case (17). A cutaway portion for exposing the fuse outlet (11e) is formed on the lower case (17). Moreover, a closing portion (16d) for covering the cutaway portion is provided on the upper case (16).

Abstract: A connection box includes a wiring board. The box includes a control board connected to the wiring board. The control board including a control device and another device separated thereinto. Another device has generation heat greater than the control device.

Abstract: In one embodiment of the present invention, a power controller for an AC load comprises: a user interface adapted to interact with a user to produce at least one user interface signal; and a control module adapted to electrically couple a line voltage supply, electrically couple the AC load, and provide electrical power to the AC load as a function of the at least one user interface signal by implementing a low-flicker, cycle-skipping control algorithm, the control algorithm comprising a plurality of cycle patterns, the cycle patterns comprising a plurality of main power levels.

Abstract: A genset controller that is configurable for controlling a variety of types of gensets, as well as a method of configuring a genset controller for controlling a genset, are disclosed. The genset controller includes a memory for storing a plurality of software routines, a personality profile data set, and a user-settable data set, and further includes a processor coupled to the memory for executing the software routines and reading data from the personality profile data set and the user settable data set to control the genset. The genset controller additionally includes an input port coupled to the memory for enabling changes to the personality profile data set and the user-settable data set to be downloaded into the memory. The personality profile data set and the user-settable data set include data that configures the genset controller for operation with a particular genset.

Abstract: An arrangement provides a power supply for low voltage circuits that is connected to receive and store energy from a power electronics switch that is connected to an alternating current supply. The power supply is operative over a wide range of input and regardless of the operating status of the power electronics switch. For each half cycle of the alternating current which the power electronic switch is to be rendered conductive, the arrangement delays for a predetermined time duration the control of the power electronic switch at the zero crossing of the half cycle. During the predetermined time duration, the power supply charges an energy storage device with sufficient energy to supply the low voltage circuit until the next half cycle.

Abstract: A heating panel has a substrate with a resistive heating material disposed thereon. The substrate can be metal with an insulating layer disposed between the substrate and the heating layer. Alternatively, the substrate can be glass ceramic. The heating layer has electrodes on opposite edges connected to different phases of a multiphase power source. Another electrode on the heating layer can be connected to a neutral of the power source. Capacitive currents caused in the substrate or a metal object on the substrate by the different phases cancel each other. Thus, leakage current through a conductor connected between the substrate and ground is minimized. The heating panel can be adapted for two phase or three phase systems. Power to the panels is controlled by solid state switches or relays. Zero crossing drivers sense supply voltages and operate the switches to balance currents in the panels.

Abstract: A duty cycle based AC power control method reduces objectionable voltage fluctuations at a frequency that causes "flicker" by shifting the frequency of actuations of controlled devices to frequencies significantly greater than and/or less than the flicker sensitive frequency. The frequency of actuations may be redistributed (1) by segmenting the devices to provide approximately equal power requirements per actuation, (2) by providing one-half cycle actuation pulses rather than one cycle actuation pulses, and/or (3) by spacing the actuations evenly over a given time period and forcing the aggregate demand to follow a slowly rising/falling envelope. The result is the minimization of power distribution at the flicker frequency.

Abstract: A primary regulator having a zero-crossing detector and a voltage reference coupled to a processor is provided. The processor controls the on time of a primary transformer via a switching device isolated from the processor via a coupler A method of regulating a power supply to maintain a desired output voltage at a load including the steps of measuring an average output voltage at a load and controlling the on time of a switching device serially connected to a primary transformer input based on the measured output voltage and a zero-crossing signal.

Abstract: Apparatus and methods for AC power regulation for a wide range of complex capacitive and inductive loads which provide substantial reduction in power consumption while also providing a leading power factor. 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 main switch consisting of back-to-back MOS Controlled Thyristor devices (MCTs) and a parallel capacitor bank in series with the load. The main switch is initially turned off slightly in advance of the load current zero crossing, and this in combination with the capacitor bank allows power to be reduced in a low noise fashion. The turn-off time is advanced gradually to regulate power at a target reduced level. At the target power level, load phase angle is measured and maintained to control the power savings ratio.

Abstract: A dimmer circuit uses a triac for controlling application of power to a hot terminal where a load will be connected. A DC power supply develops DC power for powering a control circuit which includes a zero crossing detector circuit connected to an integrated circuit chip which develops a timer pulse at the appropriate time to dim the light. The timer pulse is output to a pulse stretching circuit which actually drives the triac. The pulse stretching circuit stretches the pulse to a maximum of one-half of a cycle. This ensures that the triac will be turned on even if the inductive current delays the establishment of adequate latching current. This creates a more symmetrical waveform and results in a reduced DC offset.

Abstract: A contactor for selectively connecting at least one alternating current (AC) power line to a load and sourcing an AC current having periodic zero crossings includes a fixed contact; a movable contact mechanism; an operating mechanism for engaging and moving the movable contact to an open position in the absence of a closing signal; and a synchronized opening mechanism for disabling the closing signal in synchronization with a zero crossing of the AC current. The operating mechanism is disengaged from the movable contact, in a closed position, by a gap having a predetermined length in order that the contacts are separated at the AC current zero crossing. The contactor may further include a vacuum bottle for enclosing the fixed and movable contact therein. The movable contact may be carried within the vacuum bottle by a bottle stem which protrudes from the bottle and has a surface for engagement by the operating mechanism.

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: This present invention takes advantage of the understanding that the voltage rating associated with resistive heating element can be ignored over the common line voltage range, provided the power dissipation is controlled. This is accomplished by applying a fractional amount of power to a heating element from the power source. The method consists basically of determining, or estimating, a ratio of the amount to be applied to the amount of power available. A control signal is generated with a duty cycle approximately equal to that ratio. A zero crossing switch, under control of the control signal switches half cycles to the heating element. Thus, by applying a portion of the available half cycles to the heating element, the average power dissipation by the heating element can be controlled.

Abstract: A temperature control circuit is disclosed utilizing automatically either the electric heating (or cooling) element or a separate sensor to measure the instantaneous temperature of the thermal load device. Either a pulsating dc or an ac electric power source may be used with the temperature sensing occurring at near-zero points of the source voltage waveform. The sensor forms one element of a Wheatstone bridge which when unbalanced by a value lower than a chosen reference value, causes a monostable oscillator to flip for at least several cycles of the source power. This turns on a power SCR to feed electric current to the thermal load to increase its temperature (and resistance) until the bridge is again balanced to reverse the state of the monostable oscillator and turn off the SCR. A simple, reliable two step, user friendly calibration circuit is provided for the temperature selecting component.

Abstract: An alternating current voltage regulator providing a stable RMS output voltage across a load. The voltage applied to the load being determined by controlling the firing angle of a triac, which is controlled by the pulse width of a timing signal generated in a timer circuit. The pulse width of the timing signal is controlled by an error signal. The error signal is based upon the actual triac output voltage as compared with a comparison signal. The voltage delivered to the load is compared with a RMS reference voltage to produce the comparison signal. The potential difference between the output voltage and the comparison signal is constantly monitored to produce the error signal. The error signal is thus constantly applied to vary the pulse width of the timing signal and thus vary the firing angle of the triac in accordance with the deviation of the actual output voltage from the stable RMS reference voltage.

Abstract: A switching current converter is connected in parallel with each controlled power switch in an electric circuit so that it is allowed to operate from the input voltage and transfer energy from input to output during the turn-on periods of the controlled power switch, whereby each power switch is allowed to be turned ON when a near-to-zero voltage is present across it. The switching converter serves as an active power switch stress relieving means, resulting in minimizing the switching loss in the power switch while providing the energy for operation of the power switch in a very efficient way.

Abstract: A cooking appliance adapted for energization by a standard domestic household power supply employs a power control arrangement which accommodates electric resistive heating units designed for operation at a maximum RMS voltage level less than the RMS voltage level of the output power signal of the domestic power supply. The power control system couples power pulses from the external power supply to the heating unit at one of a plurality of available pulse repetition rates, each repetition rate establishing a corresponding RMS voltage level for application of power to the heating unit. The repetition rate associated with the maximum user selectable power setting for the appliance is effective to apply an RMS voltage level to the heating unit which corresponds to the voltage level for which the heating unit was designed.

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: In a power-factor-corrected electronic ballast, an AC/DC converter comprises a half-bridge electronic self-oscillating inverter powered from non-filtered full-wave-rectified 120 Volt/60 HZ power line voltage, and its resulting amplitude-modulated 30 kHz output voltage is applied to a series-resonant L-C circuit. The 30 kHz voltage developing across the tank capacitor of this L-C circuit is rectified and applied as direct current to an energy-storing capacitor, from which a DC supply voltage is provided to a frequency-converting ballast which, in turn, provides a substantially non-modulated high-frequency AC output voltage used for powering a gas discharge lamp via a current-limiting inductor. Trigger pulses are provided to trigger the inverter into self-oscillation at the beginning of each pulse of DC voltage provided by the unfiltered rectified power line voltage. As soon as the magnitude of the DC voltage across the energy-storing capacitor exceeds a first level, the trigger pulses cease to be provided.

Abstract: A three-phase transformer is supplied by a three-phase AC line voltage. Two phases are connected via switches comprising head-to-tail connected thyristors. The third phase is connected directly to the transformer. The switches are of the zero voltage switching type. Under steady state conditions, the start of each series of cycles is obtained by closing in a fixed order a first switch at a time near the zero-crossing of the voltage across it (alternating between series of cycles the sign of the derivative of the voltage across it immediately before it is closed) and then the second switch approximately 90.degree. after the first switch. The duration of a series of cycles if 570.degree. plus a null or integer number of periods of the AC line voltage. This is achieved by counting thyristor firing command signals from pulse transformers driven by monostables.

Abstract: An induction-hardening machine for the contour hardening of machine components such as gears includes a system processor which controls thyristor power switching circuits which supply high-power signals to an RF generator. Power switching circuits include silicon controlled rectifiers of SCR's. In order to overcome the variable "on time" characteristics of SCR devices, a zero crossing detector is implemented and time periods are calculated so that the system processor activates the SCR circuits to supply power to the RF generator at predetermined times. The system processor 12 will deactivate the SCR circuits at or just prior to a zero crossing referenced from the predetermined activation time thereby effectively controlling the one time of the SCR circuits with an accuracy of up to five ten thousandths of a second. The signal produced by the RD generator is supplied to an induction heater coil which is used to case harden the gear teeth of a machine component or gear.

Abstract: An electronic controller comprising two input terminals between which an AC line and an electrical load are connected in series. A processing unit generates a command signal to control the supply of electrical power to the electrical load which closes an electronic switch also connected between the two input terminals for connecting the AC line and the load in series in a closed loop. A power supply voltage of the controller is provided by a second power supply derived from the two input terminals, consequently from the AC line through the load when the switch is open. When the command signal is generated, an electronic circuit opens the switch which is normally closed by this command signal to maintain the power supply voltage of the controller according to an adequate standard of operation. To energize the controller, the opening of the switch is activated in a temporary and repetitive manner for a certain whole number of cycles of the sector.