Abstract: An arrangement includes a network for connection between an AC power supply and the input of a DC power supply containing rectifiers and a filter capacitor. The network forms a third order, damped low-pass filter that waveshapes the AC input current so as to either reduce or remove the magnitude of harmonics which primarily cause distortion of the input current waveform. In a preferred embodiment, the waveshaping network includes an inductor connected in series with the input of the DC power supply. A series combination of a damping resistor and a first capacitor is connected in parallel with the series inductor. A second capacitor is connected in shunt with the input terminals of the DC power supply. The waveshaping network increases the power factor and lowers the total harmonic distortion the input of the DC power supply presents to the AC power supply.

Abstract: A power conditioner for AC power lines has a choke and capacitor coupled in series across the power lines. The choke comprises a coil terminating in a line, with the line looped back through the coil. The power lines are thereby balanced to provide greater operating efficiency. Capacitors and transient suppressors (e.g., varistors) are used for transient suppression and power factor correction.

Abstract: A waveform corrector for providing correction to three-phase electrical power to correct for transient and harmonic distortion arising from electrical power cable reactance wherein the cable head end voltage and current are sensed without load end voltage or current sensing. Phase and neutral current values are sensed and corrected with predetermined values of cable resistance and inductance to provide a corrected sine wave voltage at the load end of the cable achieved by inserting a dynamic correction voltage in series with the electrical output of the waveform corrector.

Abstract: The system uses a tunable inductor in series with the piezoelectric crystal excitation transducer in the probe which has a flux modulation coil. The bias current through this flux modulation coil is controlled by the system. It is controlled such that the inductance of the tunable inductor cancels out the capacitive reactance of the load impedance presented by the probe when the probe is being driven by a driving signal which matches the mechanical resonance frequency of the probe. The resulting overall load impedance is substantially purely resistive. The system measures the phase angle and monitors the power level. The system uses this information to adjust the bias current flowing through the flux modulation coil to maintain the substantially purely resistive load impedance for changing power levels. This information is also used to adjust the frequency of the driving signal to track changing mechanical resonance conditions for the probe at different power levels.

Abstract: A power factor correction circuit for an AC to low voltage DC power supply designed to be connected to a source of AC power includes a linear transformer having primary and secondary windings, and a capacitor. In use, the primary winding is electrically connected in series with and between the AC power source and the power supply, and the capacitor is electrically connected in series with the secondary winding across the power supply, between the primary winding and the power supply. The inductance value of the primary winding is selected to remove odd harmonics from the line current drawn by the load represented by the power supply on the AC power source, and the capacitance value of the capacitor is selected to provide the reactive power load demand of the power supply. The turns ratio between the secondary winding and the primary winding of the transformer is selected to eliminate the loss of power supply operating line range caused by the voltage drop across the primary winding.

Abstract: A driver system for an ultrasonic probe using a tunable inductor in series with the piezoelectric crystal excitation transducer in the probe. The bias current through this flux moduation coil is controlled by the system such that the inductance of the tunable inductor cancels out the capacitive reactance of the load impedance presented by the probe when the probe is being driven by a driving signal which matches the mechanical resonance frequency of the probe. The resulting overall load impedance is substantially purely resistive. The system also adjusts the frequency of the driving signal to track changing mechanical resonance conditions for the probe at different power levels. This method of operation insures substantially maximum power transfer efficiency and substantially linear power control over a range of power dissipation levels.

Abstract: An arrangement for improving the power factor at the input of an off-line switching type power supply is operative to extend the duration of the pulse current conducted by the diode rectifiers. A parallel LC ringing circuit is introduced between the AC line and the rectifier of the switching type power supply to enhance the voltage enabling conduction of the rectifying diodes and hence initiate current flow through the rectifying diodes earlier in each half cycle. This extends the conduction interval of the rectifying diodes significantly and enhances the power factor at the input to the switching type power supply.

Abstract: An apparatus for accurately determining motion of a jaw without restricting its natural motion is disclosed. The apparatus comprises upper and lower jaw motion elements, at least two sensors and a phase detecting circuit. The sensors detect a phase of an alternating current induced within them.

Abstract: A power-factor correction system for reactive power control and concomitant power factor correction adapted to cooperate with a line supplying power at a given line voltage from a power generator to an inductive load via a given path, includes a reactive power compensating device in shunt with the line supplying power, and is adapted to be connected in shunt with the inductive load.

Abstract: An electronic ballast for energizing one or more gaseous-discharge lamps and for regulating the power consumed thereby, the ballast including a power supply for providing a source of DC power between a pair of outputs, a pair of transistors connected as switches in series between the power-supply outputs, the transistors for selectively coupling to the juncture thereof positive and negative potentials, a voltage-conditioning and current-limiting network for energizing the lamp from the potential developed between the transistor juncture and a power-supply common, and a pulse generator for developing pulses for driving each of the transistors in turn whereby a potential is developed at the transistor juncture which alternates as positive-going and negative-going pulses each separated by a dead time, the pulse generator for monitoring the power consumption level of the lamp and responsive thereto operative to vary the frequency and/or the width of the transistor driving pulses whereby the lamp consumption is re

Abstract: A device generates a signal corresponding to a variable magnitude associated with the reactive power of an arc furnace, in order to control a reactive power compensator. It comprises a reactive power or voltage demodulator and a set of filters connected to the output of the demodulator. The set of filters comprises active bandstop filters having a bandwidth of .+-.F relative to frequencies of 2f.sub.O, 4f.sub.O and 6f.sub.O and narrowband active bandstop filters having a bandwidth of substantially .+-.2 Hz relative to frequencies of f.sub.O and 3f.sub.O. f.sub.O is the supply frequency and F is approximately f.sub.O /2. The device further comprises a phase advance corrector circuit operative in the frequency band O-F connected to the output of the set of filters.

Abstract: A static VAR generator for providing reactive compensation incorporating a malfunction detector. The static VAR generator comprises a reactance which is linearly responsive to a first linearized control signal and produces an output signal proportional to the reactive compensation which provides a feedback signal. A director control uses the feedback signal and an adjustable reference signal to provide the first linearized control signal based on the difference between the reference and feedback signals. A tracker controller provides a second linearized control signal based on the reference and feedback signals. The second control signal is compensated by an equalizer that determines the difference between the first and second control signals. The compensation counters the difference between the first and second control signals caused by the offset and component tolerances in the two controllers and makes the second control signal substantially equal to and track the first control signal.

Abstract: A power factor correcting system for compensating a lagging power factor reactance for an electric load plurality fed from at least one pair of incoming service lines, comprising, in combination: capacitors for producing leading reactive power; a series transformer, having primary and secondary winding, the secondary winding being connected in series with affected power lines; a variable transformer fed from the service lines and feeding the primaries of the series transformer; the capacitor instrumentality being fed from the affected incoming power lines with a voltage which varies in magnitude as needed, being the sum of the power line voltage plus/minus the variable series transformer secondary voltage; with the variable transformer through feeding of the primaries of the series transformer causing the required voltage variability in the series transformer secondary and subsequently in the feeding voltage applied to the capacitor; sensing instrumentality to detect presence of lagging reactive power requiri

Abstract: To provide a power rectifier for connection to an a-c power network which has low ripple at the d-c output, and low harmonic content at the a-c side, particularly for feeding a d-c - a-c inverter frequency generator providing output in the audio or low supersonic range for supply of gas discharge or fluorescent lamps, a wave-shaping network is connected to the a-c side of a standard bridge rectifier unit such that the a-c power applied to the rectifier is of approximately trapezoidal or rectangular or square-wave shape; a suitable network is the combination of an inductance (D) and a storage capacitor(C1) in a T-network or in a series resonant circuit, in which the quadrature VA of the choke (D), at network frequency, is about 60% of the power to be supplied by the rectifier, with a capacitor (C1) in a T-network configuration of such value that the resonant frequency of the L/C circuit is about 2.2 to 2.6 times network frequency or equal to network frequency, when in a series resonant circuit.

Abstract: The high voltage testing system contains a series resonant circuit connected to a voltage source with a continuously variable frequency, whereby the insulation, connected in series with the inductor, which is being tested, either exclusively or at least partly, forms a part of the capacitance. The inductance may consist of several high voltage inductors constructed of modular elements. It is advantageous to use bar-core chokes.Preferably, the bar-core choke is suspended in the mass center by means of a mounting plate. Suitably, the coil of the inductor consists of two windings, each having a trapezoidal cross section.A static frequency converter would be suitable as a voltage source with variable frequency; the converter could be a direct converter built to act as an oscillating circuit converter, operating within the resonance frequency and with pulse-width control. At least one high-voltage capacitor may be connected in parallel to the insulation for the adjustment of the desired frequency.