Abstract: A DC electrical power supply system for converting AC power to DC power for various telecommunications equipment loads includes plural rectifiers mounted on one or more shelves and adapted to be inserted on and removed from said shelves, at will. One or more voltage converters may be inserted and removed from said shelves at will and include adapter plates for supporting the converters in place of a rectifier unit. The power supply system includes a frame supporting the shelves and a cabinet which includes busworks for connecting the rectifiers to circuit breaker tiers and to a battery pack. Low voltage disconnect devices may be interposed in the buswork at selected locations to provide operation in a battery protection mode, load protection mode and load shedding mode. The circuit breaker tiers, buswork, shelving, rectifier units and converters are all accessible for connection and disconnection from the front side of the power supply system.

Abstract: A power supply circuit receives and rectifies a three phase power source. A first capacitor is coupled to filter and store the rectified three phases and supply the stored energy to a DC/DC converter. The first capacitor is large enough, when all three phases are present, to filter the rectified input power and supply rated voltage to the DC/DC converter between peaks in the phases, but not too large as to adversely affect the power factor. However, when one phase drops out, additional capacitance is required to maintain rated voltage to the DC/DC converter during the periodic absence of the one phase. Thus, a switch and a second capacitor are connected in series with each other and in parallel with the first capacitor. In response to absence of one of the phases, the switch is activated to couple the second capacitor to filter and store the rectified two phases and supply the stored energy to the DC/DC converter.

Abstract: In a delta-connected power supply system, phase switching circuits are employed and are activated during the failure of one of N+1 converter units. This activation is employed even though there has been no outage in any one of the input phases. The result is two operating converters running in effect as three-phase converters. Since each of the converters then acts as a full wave three-phase bridge with a resistor load, the line currents are perfectly balanced although unity power factor is not maintained during this non-normal mode of operation. In such circumstances, higher power factor is temporarily sacrificed to achieve continuous operation and therefore higher overall system reliability.

Abstract: A snubber network for a power conversion circuit operated in discontinuous conduction mode includes a snubber capacitor, an isolation diode and an active reset circuit. The snubber capacitor is connected to the output of the isolation diode, both of which are connected across a main switch of the power conversion circuit. The active reset circuit, connected between the input and output of the isolation diode as well as the input and output of a boost diode, is responsive to a reset signal for active resetting of the snubber capacitor within the normal boost cycle of the power conversion circuit. Upon receipt of the reset signal, energy held by the snubber capacitor is recovered by the reset circuit and subsequently transferred to the output of the power conversion circuit with turn-off of the main switch of the power conversion circuit. This occurs contemporaneous with the power conversion circuit's delivery of converted power to its output.

Abstract: These and other objects are achieved by an improved active power line conditioner in accordance with the invention. The active power line conditioner includes series inverter coupled to an energy input source, and a parallel inverter coupled to a non-linear load. The non-linear load is powered by a load current which includes fundamental components and harmonic components. An energy storage element is electrically connected between the series inverter and the parallel inverter. A fault condition shorting circuit is supplied in accordance with the invention. The fault condition shorting circuit is coupled to a secondary transformer winding within the series inverter. The fault condition shorting circuit includes a diode bridge which conveys diode bridge current only in the presence of an overvoltage or overcurrent condition. A threshold device is connected to the diode bridge and conducts threshold device current in response to the diode bridge current.

Abstract: A pulse generator circuit which comprises a power supply source for outputting a high voltage signal. A first capacitor is charged with the high voltage signal output by the power supply source. A load device is supplied with the high voltage signal charged in the first capacitor. A semiconductor switch together with the first capacitor and the load constitute a closed loop. A first diode is inserted between the power supply source and the closed loop. A second diode is inserted in a closed loop and operates to suppress electrical vibrations. A second diode may have an opposite polarity to that of the first diode. A snubber circuit may also be inserted in parallel across the second diode.

Abstract: An electronic circuit senses that at least one circuit of rectifying diodes has been opened and response initiates an alarm. To sense one of the diode circuits being opened, the electronic circuit detects a temporary crossing of a low threshold by a DC voltage supplied at the rectifier output. The circuit is particularly applicable to high-power transformer-rectifiers aboard aircraft.

Abstract: A power supply including a source of AC power, a filter including inductive elements, and rectifying circuitry. Where the AC source comprises a sinewave source, the filter includes inductive and capacitive elements; and where the AC source comprises a square wave source, the filter includes only inductive elements.

Abstract: A universal pressure measurement interface ("UPMI") according to the invention enables interfacing of a multiplicity of pressure transmitters to a data acquisition system. The UPMI provides the necessary DC power and signal flow for field test measurements and is suitable for direct application in various sites with line voltage of from 100 to 240 VAC at 50-60 Hz.

Abstract: An intrinsically safe power supply unit, more particularly for face supports in mining, comprising an ac transformer connected to a rectifier and power resistors for limiting the current and connected to the dc voltage output, wherein the ac voltage transformer is a resonance transformer which stabilizes the secondary voltage, and the dc voltage occurring behind the power resistors is kept constant by three voltage limiters connected in parallel.

Abstract: A three phase loss protection circuit for a three phase rectifier. The rectifier includes a circuit which inhibits its operation when either of two of the three phases are lost. In response to the loss of the third phase, the loss protection circuit causes one of the other two phases to be lost at the input to the inhibiting circuit. The loss protection circuit does not interfere with the operation of the inhibiting circuit when either of the two phases are lost. In an alternative embodiment, the loss protection circuit includes circuitry to ensure that the rectifier is inhibited even though part of a lost phase may be recreated by the rectifier's input filter.

Abstract: A protective grounding and referencing arrangement for a high-voltage, high-energy bulk supply is provided in the present invention. Isolation from ground is provided through the use of an isolation transformer connected between the a-c utility supply and the rectifiers which are provided for conversion to d-c. The d-c bus and its energy storage capacitors are then referenced to ground by a high resistance divider network. In such an arrangement the likelihood of an insulation breakdown to ground is significantly reduced. More importantly, in the event that such a breakdown should occur from one or the other terminal of the d-c bus the fault currents that result are limited by the referencing arrangement to a safe level. The energy hazard is thus very significantly reduced for the equipment.

Abstract: A DC-DC converter of simple arrangement that effectively utilizes a negative voltage to improve loss of power. This DC-DC converter is suitable as a dc power source for an electronic flash of a camera.

Abstract: A high voltage power source for supplying a DC high voltage to a discharge tube, can detect an abnormality when created at the discharge tube side and stop its output. The high voltage power source is provided with a detector circuit which detects when the DC high voltage is larger than a predetermined reference value and a control circuit which cuts off the output of the DC high voltage in response to the above detection. When an abnormality occurs at the discharge tube, for example, non-operation or unstable operation occurs, since a load becomes lighter than normal, and the DC high voltage to be supplied to the discharge tube becomes higher than normal and is detected by the detector circuit so that the control circuit responds to the detected high voltage and cuts off the output of the DC high voltage.

Abstract: In the control apparatus of an AC/DC power converter, the occurrence of a single-phase line-open in the AC power line is detected by an open-circuit detector so that a detection signal is generated. The control angle of a converter on the side of occurrence of the single-phase line-open is kept at a given value based on the detection signal. At the same time, the current set value of the automatic current regulator is also kept at a fixed value based on the detection signal.

Abstract: A voltage limit circuit for phase controlled rectifiers avoids shoot-through and limit cycling conditions by limiting the d.c. output voltage of the rectifier bridge. The circuitry follows a voltage reference signal as long as the reference signal is less than an input derived from the a.c. voltage applied to the bridge, reduced by the volt-seconds required for commutation. Should the reference signal exceed the a.c. derived input, the a.c. derived input limits the maximum available d.c. voltage. To this end, a voltage reference signal provides an output signal corresponding to the desired output voltage of the bridge. A slew limit circuit limits the rate by which the output signal may be changed. A magnitude limit circuit is coupled to the output of the slew limit circuit and provides a reference signal for the firing circuit of the rectifier bridge. The magnitude limit circuit receives the a.c.