Abstract: A thyristor circuit including a primary winding and at least one secondary winding and first and second bipolar thyristor switches connected across respective connections of the secondary winding. The first bipolar thyristor switch bridges N.sub.1 turns of the secondary winding, while the second bipolar thyristor switch bridges N.sub.2 turns of the secondary winding, wherein N.sub.2 is less than N.sub.1. The product between the maximum forward current of the second bipolar switch and the number of turns N.sub.2 is greater than the product between the latching current of the first bipolar thyristor switch and the number of turns N.sub.1 thereof. The second bipolar thyristor switch thus makes it possible to short-circuit the portion of the secondary winding bridged thereby, for operation as a switchable choke, e.g. in a reactive compensator, or as a variable power supply when supplemented by additional components.

Abstract: A static VAR generator for providing reactive power compensation to an n-phase AC network subject to transient surge currents utilizing mechanically switched shunt circuits in parallel with the thyristor arrays.

Abstract: In this three-phase filter circuit system for static converter systems and particularly high-voltage direct-current short ties, at least two high-pass filters are provided which are connected in parallel. Each high-pass filter consists of a choke connected in parallel with a resistance and, in series with both, a capacitor and can be individually connected to the three-phase busbar via a switch. The filter circuits are used not only for reducing harmonics but also as compensating devices, which can be switched in steps, for the reactive power requirement of the static converters so that in the lower partial load range of the system one of the filter circuits is disconnected for reasons of reactive power balance. In order to improve the filtering effect in this lower partial load range, a bus-coupler switch connecting in each case the common junctions of capacitor, resistance and choke of the high-pass filters is closed.

Abstract: A synchro power amplifier and control circuit for an inductive load has a plurality of synchro leg amplifiers connected to the load. Each amplifier has an interstage transformer for deriving samples of current drawn by the load. A multiplicity of capacitors are respectively connectable in parallel with the (load) upstream of the amplifiers by switches in a circuit 10 responsive to the voltage/current phase angle of the power driving the load, to compensate for the inductance of the load.

Abstract: A control method of the invention is formed with the steps of when a margin angle .gamma. reaches a given minimum margin angle .gamma.min during the operation of a rectifier and inverter, a shunt reactor is disconnected from, or a shunt capacitor is connected to, an AC line of the inverter, and when the margin angle .gamma. exceeds the minimum margin angle .gamma.min by a predetermined value, the shunt reactor is connected to, or the shunt capacitor is disconnected from, the AC line.

Abstract: Power factor regulating method and an apparatus embodying the method in which each of three condensers, which are to be connected to each phase of a three phase distribution line, is preliminarily charged with approximately peak line voltage while a load connected to a distribution line is opened in order to lessen impulse waves that are brought about at the time of connection of the condenser to the appropriate phase of the power line. The present method needs no conventional discharging coil.

Abstract: A capacitively ballasted low voltage lamp comprising a main capacitor connected electrically in series with the lamp, across an alternating current source, and one or more auxiliary capacitors that can be connected electrically across the main capacitor by switching means for one or more source waveform cycles. The minimum lamp current is established by the main capacitor, with additional lamp current flowing through one or more auxiliary capacitors during one or more source waveform cycles.

Abstract: A capacitively ballasted low voltage lamp utilizing a main capacitor connected electrically in series with the lamp, across an alternating current source, and one or more auxiliary capacitors that can be connected electrically across the main capacitor by switching means for one or more source waveform cycles. Each switching means comprises a unidirectional conductive device electrically connected in parallel with an active switching device. The minimum lamp current is established by the main capacitor, with additional lamp current flowing through one or more auxiliary capacitors during a source waveform cycle or integral multiples thereof.

Abstract: The DC to AC power inverter is of the class B, C, D or E type and includes a battery, at least one power SCR and associated capacitor circuitry, at least one input winding on a main transformer core and at least one output secondary winding on the transformer core. Such inverter requires a quiescent current to establish operating current for capacitor commutation charge and includes a feedback loading circuit for feeding current generated by the quiescent current back to the battery. The inverter also includes a self-detecting load demand circuit coupled to a line from said output winding for cyclically energizing the inverter, for sensing a minimum AC load and for holding said inverter in an energized state until less than a minimum AC load is sensed during an energizing cycle.

Abstract: A power supply, operating at line frequencies, for energizing a low-voltage lamp and like loads, utilizes a main capacitor in series with the load across the A.C. line source, and an auxiliary capacitor connected across the main capacitor by a switching device during a selected portion of the source waveform cycle. The minimum load current is established by the main capacitor, with additional load current flowing through the auxiliary capacitor during those portions of the source waveform cycle when connected, whereby the load current may be adjusted over a range established by the magnitude of the main and auxiliary capacitors. An open-loop circuit is disclosed for controlling the portion of the cycle during which the auxiliary capacitor is connected.

Abstract: A power supply providing power to a low voltage lamp utilizing a main capacitor connected electrically in series with the lamp, across an alternating current source, and an auxiliary capacitor connected electrically across the main capacitor by a switching device during selected portions of the source waveform cycle. The minimum lamp current is established by the main capacitor, with additional lamp current flowing through the auxiliary capacitor during portions of the source waveform cycle when the auxiliary capacitor is electrically connected across the main capacitor. The load current is adjusted over a desired range established by the magnitude of the main and auxiliary capacitors.

Abstract: An electrical resistance heater controller is provided with a plurality of circuit branches connected in parallel with each other and in series with a heating element and an external AC power source. Each circuit branch includes the series connection of a capacitor and a solid state switch. The switches are controlled by a gating device to switch during the zero crossing of the AC source voltage waveform. Power delivered to the heating element is controlled by varying the amount of series capacitance in the circuit.

Abstract: A capacitor unit including a capacitive element connected in parallel with a discharge resistor is provided with a switch in series with the resistor. This switch responds to power frequency current flowing through the capacitive element such that it opens to remove the discharge resistor from the circuit when power frequency current is flowing through the capacitor unit and closes when power frequency current stops, thus reinserting the discharge resistor to eliminate any residual charge remaining on the capacitive element.

Abstract: A line drop compensator device for an aircraft flight line electrical distribution system has a plurality of service points connected at spaced locations along a three-phase power line and the current flow at each service point is sensed. In response to the sensed current flow, capacitance is added between the conductor lines and neutral of the power line so as to correct the voltage in proportion to the demand. Compensation is thus added proportional to the current drawn from the line.

Abstract: A DC to AC power inverter for transforming a DC voltage to an AC voltage, and supplying the AC voltage through a transformer to a load, wherein the transformer is provided with a number of taps to permit connection of a capacitor through switch means to a selected tap thereby to improve matching the load impedance with the inverter to improve efficiency by virtue of improving power factor.