Abstract: A method and apparatus are directed to a dynamic means for correcting imbalance and harmonic distortion in an electrical system. In one embodiment, the device includes an imbalance and harmonics measurement module configured to measure power parameters for determining imbalance and harmonics within the electrical three-phase system. Within this system a series of capacitors are configured to respond to measured demands reported and designated to correct for imbalance and harmonics distortion. The device is networked among various source load controllers are responsible for designating master and slave relationships within the closed system.

Abstract: A device for improving efficiency of an induction motor soft-starts the motor by applying a power to the motor that is substantially less than the rated power of the motor then gradually increasing the power while monitoring changes in current drawn by the motor, thereby detecting when maximum efficiency is found. Once maximum efficiency is found, the nominal motor current is found and operating ranges are set. Now, the phase angle between the voltage and the current to the motor is measured and power to the motor is increasing when the phase angle is less than a minimum phase angle (determined during soft-start) and power to the motor is decreased when the phase angle is greater than or equal to the minimum phase angle as long as the voltage does not fall below a minimum voltage determined during soft-start.

Abstract: The invention relates to a method for operating an electric motor (2) having a phase angle control with the following steps: Applying an AC voltage to a series connection of the electric motor (2) and a switching element (4), particularly a triac, wherein the switching element (4) connects through by applying an ignition signal and suppresses the flow of a current if the amount of current falls below a holding current; determining the time of a zero crossing of a virtual motor current that would flow if the switching element (4) were connected through; and turning on the switching element (4) at an activation time that is dependant on the time of the zero crossing of the virtual motor current.

Abstract: A vertical SCR switch to be controlled by a high-frequency signal having at least four main alternated layers. The switch includes a gate terminal and a gate reference terminal connected via integrated capacitors to corresponding areas. In the case of a thyristor, having on its front surface side a main P-type semiconductor area formed in an N-type gate semiconductor area, a first portion of the main area being connected to one of the main areas, a second portion of the main area is connected to one of the control terminals via a first integrated capacitor, and a portion of the gate area being connected to the other of the control terminals via a second integrated capacitor.

Abstract: A driving circuit for electrical nailing gun is disclosed to include a capacitive charging/discharging unit formed of a first resistor, a first diode, and a capacitor connected in series and connected with two opposite ends thereof to the positive and negative poles of AC power source, an excited field unit formed of a first coil and a first electrically-controlled switch connected in series and having two opposite ends connected in parallel to the capacitor, and a control unit electrically connected to the first electrically-controlled switch for activating the first electrically-controlled switch.

Abstract: A method for controlling an SCR-type switch, consisting of applying on the switch gate several periods of an unrectified high-frequency voltage, the power of one HF halfwave being insufficient to start the SCR-type switch.

Abstract: A method for controlling fault interruption in a high voltage electrical energy transmission system semiconductor high voltage electrical energy transmission switching system which includes a multiple stack of power semiconductor SCR thyristor circuit sections arranged for single phase or three-phase operation with each section of the stack comprising; a pair of input and output terminals, a plurality of switching thyristors connected in series between the input and output terminals, an auxiliary power transformer having at least three windings with first and second windings interconnecting the input and output terminals of one section to the respective output and input terminals in each adjacent section of the stack such that the voltage difference between the first and second transformer windings is limited to the maximum voltage across the section.

Abstract: An AC transfer switch (ATS) is provided for switching a system load between at least two AC lines. A first bridge rectifier is connected to a first AC line for providing a first full wave rectified AC waveform. A first pair of oppositely poled silicon controlled rectifiers (SCRs) is coupled to the first bridge rectifier and to the system load. A second bridge rectifier is connected to a second AC line for providing a second full wave rectified AC waveform. A second pair of oppositely poled silicon controlled rectifiers (SCRs) coupled to the second bridge rectifier and to the system load. Control logic is coupled to a gate input of the first pair of oppositely poled silicon controlled rectifiers (SCRs) and a gate input of the second pair of oppositely poled silicon controlled rectifiers (SCRs) for applying one of the first full wave rectified AC waveform or the second full wave rectified AC waveform to the system load.

Abstract: An analog voltage pulse generator, including a first break-over component of Shockley diode type to activate a rising edge of a pulse on an output terminal and a second component of thyristor type to block the first component and deactivate the pulse.

Abstract: An integrated ringing access switch circuit for telecommunications switching applications that provides improved dV/dt sensitivity at low operating power by using a pilot controlled rectifier, such as an SCR, that conducts at low ringing signal currents and operates to steer a bias current for causing a relatively larger controlled rectifier in parallel therewith to become conductive during higher load current operation. Also included is circuitry for preventing inadvertent turn-on of the SCRs in response to transient signals.

Abstract: A solid state relay includes a power semiconductor controlled by a gate electrode. A current detector provides a signal which is a function of the absolute value of the current through the power semiconductor. An evaluation circuit coupled to the current detector receives the current signal. The current detector may include a ferromagnetic core surrounding a conductor coupled to the power semiconductor, a coil wound around the core, and an oscillator generating a carrier signal and a detection circuit, both coupled to the core. The current detector is used to control latching of the relay and to generate status signals if predetermined parameters are exceeded.

Abstract: An apparatus for protecting an integrated circuit against damage from electrostatic discharges (ESD) includes a single ESD bus that is connected to multiple input pads through a respective diode. The ESD bus is isolated from the positive power supply bus V.sub.DD. The ESD bus is coupled to the negative power supply bus V.sub.SS by a FET-triggered SCR circuit. ESD charge on an input pad forward biases the respective diode and charges the ESD bus. When the voltage of the ESD bus reaches a predetermined threshold voltage, the FET breaks down, and triggers the SCR circuit to shunt the charge on the ESD bus to V.sub.SS. The threshold voltage is selected such that, in normal operation, voltages higher than V.sub.DD may be applied to the input pad without input leakage current.

Abstract: A key switch control device includes a gate controller and a load connected in series to AC power supply, a control circuit connected to the key switch to receive from it a pulse signal for controlling the gate controller and the load, enabling AC power supply to be connected to the load when the key switch is clicked once, or disconnected from the load when the key switch is clicked at least twice. The control circuit includes an oscillator, a time pulse counter, a periodic comparator, a power modulation recognizer, and an output drive.

Abstract: An SCR firing circuit is provided which includes a plurality of opto-couplers, diodes, a capacitor and an SCR, utilized to control the AC power applied to a load, such as a vibratory feeder. In various embodiments of the invention, one or more opto-couplers act as solid state switches and also isolate a control signal from the AC line voltage. The capacitor is charged from an AC power source through the diode during a half cycle of the AC line voltage, and remains charged until the SCR is triggered. In response to a control signal rendering the opto-couplers conductive, the capacitor is discharged through the opto-couplers to fire the SCR and provide AC power to the load. A back-to-back SCR firing circuit is also provided which fires a first SCR when a line voltage is positive and which fires a second SCR when the line voltage is negative, which may be utilized to adjust the frequency of the application of power to the load independently of the frequency of the AC power supply.

Abstract: A gate drive circuit for a silicon controlled rectifier (SCR) connected in an a-c power circuit includes a voltage divider network connected between a d-c voltage source and the SCR for developing a varying voltage on a control node, depending upon whether the anode-to-cathode a-c voltage of the SCR is positive or negative. A first switching transistor, responsive to the control node voltage, controls conduction of a second switching transistor connected between the d-c voltage source and a voltage regulated driver circuit. In this way, a constant drive current is applied to the SCR gate only while the anode-to-cathode voltage of the SCR is positive.