Abstract: A circuit arrangement for reducing unidirectional flux component in a transformer core includes a compensation winding magnetically coupled to the transformer core, a transductor series connected with the compensation winding in a compensation current path, wherein the compensation current path has two parallel branches each containing a power winding of the transductor and an uncontrolled valve connected in series, where flow directions of the valves run counter to one another, and where each power winding is magnetically coupled to a control winding via a saturable transductor core, and includes a controller to which a detector supplies magnitude and direction information of the unidirectional flux component, and which generates a control variable supplied to each control winding such that the saturation state of the transductor core is variable such that a compensation current is formed in the compensation current path that counteracts the unidirectional flux component in the transformer core.

Abstract: A steel sheet shape control method includes, (A) setting a target correction shape of the steel sheet at a position of an electromagnet to a curved shape, (B) measuring a steel sheet shape when electromagnetic correction is performed, (C) calculating the steel sheet shape in a nozzle position based on the steel sheet shape, (D) repeating (B) and (C) by resetting the target correction shape to a curved shape having a smaller amount of warp, (E) when the amount of warp of the steel sheet shape at the position of the nozzle is less than the upper limit value, (F) calculating vibration of the steel sheet at the position of the nozzle, and (G) adjusting a control gain of the electromagnet until amplitude of vibration is less than a second upper limit value when the amplitude of the vibration is equal to or more than the second upper limit value.

Abstract: A device for reducing a magnetic unidirectional flux fraction in the core of a transformer is provided. The device has a measuring device that provides a sensor signal corresponding to the magnetic unidirectional flux fraction, a compensation winding that is magnetically coupled to the core of the transformer, a switching unit arranged electrically in a current path in series with the compensation winding in order to feed a current into the compensation winding. The action of the current is directed opposite to the unidirectional flux fraction. The switching unit can be controlled by a regulating variable provided by a control device and can be switched into a conductive state during a predefined time interval and in accordance with the regulating variable, the switch-on time being mains-synchronous. A device for limiting the current in the current path is provided and the sensor signal is fed to the control device.

Abstract: Apparatus and method for controlling the frequency of the current in the excitation coil of a handpiece of a dental magnetostrictive ultrasonic scaling unit, or a similar transducer. A microprocessor continually samples predetermined functions of the current through the excitation coil, and periodically adjusts the frequency, by performing a coarse-stepped frequency scan, followed by a fine-stepped frequency scan until the function samples are close to predetermined optimum values. The functions can include the peak of the current and the peak of a high-pass filtered version of the current. The frequency adjustment is performed each time the handpiece is energized by the practitioner, and at frequent intervals thereafter, assuring automatic optimal frequency at all times and under all conditions. Apparatus according to the invention does not require sensing coils or complex power- or impedance-sensing circuitry and covers a wide range of resonant frequencies for different handpiece- and insert types.

Abstract: A charging control apparatus comprising: a voltage control unit in a charging apparatus configured to control generation of an output voltage and a power supply voltage, the charging apparatus being an apparatus configured to generate, from a voltage of an input power supply applied through a relay, the output voltage for charging a battery and the power supply voltage for control; and a relay control unit operated by the power supply voltage, the relay control unit configured to drive the relay so as to stop applying the voltage of the input power supply to the charging apparatus, when detecting a standby state in which the battery is not being charged, and drive the relay so as to increase the power supply voltage by applying the voltage of the input power supply to the charging apparatus, when the power supply voltage decreases below a predetermined level.

Abstract: Embodiments include methods and apparatus for testing an electrical system (e.g., of an electric vehicle) that includes a high voltage (HV) energy storage system, HV contactors, one or more energy consuming components, one or more energy supplying components, an HV bus, discharge circuitry, and a control system. The control system is adapted to perform a method that includes performing a first diagnostic test to test the functionality of the HV contactors, and performing a second diagnostic test to test the functionality of the discharge circuitry. When the first and second tests have passed, the control system allows the HV contactors to be closed to enable an exchange of energy between the HV energy storage system, the one or more energy consuming components, and the one or more energy supplying components.

Abstract: Apparatus and method for controlling the frequency of the current in the excitation coil of the handpiece of a dental magnetostrictive ultrasonic scaling unit, or similar transducer. A microprocessor continually samples a predetermined function of the current through the excitation coil, and adjusts the frequency for a function maximum, performing coarse and fine frequency adjustments. The function can be proportional to the current, its time-derivative, or combination thereof. A voltage-controlled oscillator is employed, controlled by pulse-width modulation from the microprocessor. The base frequency scan is performed each time the handpiece is energized by the practitioner, assuring automatic optimal frequency adjustment at all times and under all conditions. Apparatus according to the invention does not require transformers, sensing coils, or complex power- or impedance-sensing circuitry, and covers a wide range of resonant frequencies for different insert types.

Abstract: A switchgear comprises a switching device, such as a relay, with a switching mechanism. A printed-circuit board that is provided with at least one electronic component is electrically connected to the switching device to form a supplementary electrical circuit, which receives an operating voltage supplied to the switching device.

Abstract: An uninterruptible power supply (UPS) includes a power conversion circuit and a relay. The relay is configured to couple and decouple a power source to and from an input of the power conversion circuit. The control circuit is operative to apply a coil current to the relay to sense the coil current and to detect an operational failure of the relay from the sensed coil current. Related methods of operating such UPSs are also provided.

Abstract: A fuse and filter arrangement having a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse includes of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode. The fuse and filter arrangement includes a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: The present invention relates to a safety switch on a circuit connecting a power supply to a load. The safety switch includes a diode in series between the power supply and the load where the diode is also in series between the power supply and the latching coil.

Abstract: An optical control electromagnetic wave circuit comprises a unit composed of a semiconductor layer, a transparent substrate, and a transparent grounded conductive layer and a displaying unit. The semiconductor layer is formed on the transparent substrate, and the photoconductive layer is formed on the opposite surface of the transparent substrate. The displaying unit faces the transparent grounded layer. The shape of the radio wave circuit which is displayed on the displaying unit is mapped on the semiconductor layer to form the radio wave circuit.

Abstract: A fault indicator for detecting the occurrence of a fault current in a monitored conductor includes a rotatably mounted indicator flag. The flag is positioned in either a reset indicating or a fault indicating state by a magnetic pole piece, which is magnetized in one magnetic direction or the other by momentary application of a current in one direction or the other to an actuator winding on the pole piece. An auxiliary magnetic circuit comprising an auxiliary pole piece magnetized by the actuator winding, a reed switch and a bias magnet magnetically aligned to oppose the reset magnetic orientation and reenforce the trip magnetic orientation of the magnetic pole piece provides contact closure upon occurrence of the fault current.

Abstract: A very low cost method of driving the coil of a meter disconnect switch utilizes the 60 Hz signals from an existing power supply rectifier to generate properly phased gate drive signals to SCRS, with only one stage of isolation.

Abstract: A memory card connector (10) includes an insulative housing (20) having a plurality of cavities (26) extending therethrough in a front-to-end direction for reception of a corresponding number of contacts therein. Ejection mechanism includes a pivotal lever (70) adapted to be rotatable with regard to the housing (20), and an actuation bar (80) adapted to be lengthwise moved wherein such lever (70) and actuation bar (80) are linked with each other. A pushing block (90) positioned on the actuation bar (80), has a pushing or operation surface (95) which laterally projects out of the lengthwise axis (Z) of such actuation bar (80) so that the actuation bar (80) can be rearwardly moved by easily manually approaching such operation surface (95) from an exterior, thus actuating such pivotal lever (70) to rotationally move for ejection of the memory card inserted within the connector (10).

Abstract: Detecting the inoperability of a plurality of printing element drivers without printing involving sequentially energizing each of the drivers with a shortened time duration pulse sufficient to produce a signal in indicating operability and/or inoperability but not sufficient to cause printing.