Abstract: A valve stack for high voltages includes a number of electrically interconnected valve modules, some of which are disposed one above the other. To prevent a large fire in a valve module from spreading upwards to valve modules positioned above it, fire screens are arranged between valve modules located one above the other.

Abstract: A power supply wherein the rectified output of two or more transformer secondaries are connected in series and then parallel each half cycle of an alternating current energization signal. Logic circuitry monitors the rectified output and automatically switches from a series to a parallel connection to provide a regulated power supply output.

Abstract: In a high-voltage power device for X-ray tubes, a single magnetic circuit is used to couple a primary circuit to two separate secondary circuits. Each of these secondary circuits comprises a series of secondary windings, each connected to a rectifier-doubler circuit constituted by diodes, borne by a printed circuit, and by capacitors, borne in a cellular compartment. This arrangement makes it possible notably to double the output high voltage or to obtain perfectly symmetrical high voltages in a device that occupies less space.

Abstract: The invention relates to a new arrangement of at least one valve stack (2) for high voltage direct current in a valve hall (1). Said valve stack (2) has a voltage to ground which, in operation, increases along the stack (2). The invention comprises arranging the stack (2) in a substantially lying position at such a distance from the floor and roof (9), respectively, of the valve hall (1) that the smallest electrical flashover distance between live parts on the stack (2) and said floor and roof (9), respectively, is at least contained. Further, the electrical connection is arranged via bushings through the roof (9) of the valve hall (1).

Abstract: A high voltage high power DC source includes a magnetic flux pole structure responsive to a high frequency, relatively low voltage source inductively coupled to the pole. Multiple AC to DC converters inductively coupled to the pole are connected in series, stacked relationship with each other, to derive the high voltage, high power DC output. Each stage includes a pair of oppositely wound planar coils on opposite sides of a printed circuit board. The printed circuits of the different stages are displaced from each other and a coil driven by the high frequency source.

Abstract: With respect to their connection to snubber capacitors (C1, C2), a discharge resistor (12) connecting these snubber capacitors, and a link capacitor bank (3), inverter circuits with GTO thyristors (T1, T2) connected in series have parasitic leakage inductances which limit the level of the permissible link direct voltage. In order to reduce the leakage inductances, the snubber capacitors (C1, C2) are surrounded by effectively conducting capacitor covers (17). Sheet-metal shielding covers are fitted over the two ends of the discharge resistor (12). Parallel and series connected capacitors of the link capacitor bank (3) are connected to the positive/negative terminals (23, 24) of the GTO thyristors (T1, T2) in the middle of a heat sink connecting strainer (33), the supply leads being guided essentially parallel and the capacitors being arranged in opposite planes.

Abstract: A hybrid high voltage transformer includes three nesting cylindrical coil forms. The inner coil form supports a primary winding and the two outer coil forms support secondary windings that substantially overlie the primary winding. Each of the secondary winding coil forms includes a plurality of circumferential walls forming individual compartments for supporting a multilayered group of coil turns in a substantially uniform pattern over the coil form. The outer coil form includes an upraised central portion to permit tapping of the secondary winding thereon for a DC focus voltage at AC ground. The coil forms include protrusions for supporting connection posts for making electrical connections and supporting electrical components. The two secondary windings are wound in opposite directions.

Abstract: An X-ray imaging system includes an vacuum tube, which is biased by a high voltage power supply connected to the tube by two shielded cables. The cables collectively have a plurality of conductors which are coupled at one end to the high voltage power supply. The other end of each conductor is coupled to a component of the vacuum tube by a separate inductor. During a voltage breakdown of the vacuum tube, the inductors depress electrical current flow between the anode and the cathode of the tube to reduce the erosion of tube components which results from the discharge. This current is in part due to the energy stored in the cable, which is not depressed by conventional current limiting circuits in the high voltage power supply. Voltage limiting devices connected to the tube prevent ringing in the cables from generating excessively high voltage levels.

Abstract: A flyback transformer comprising a magnetic core assembled by joining together a pair of first and second U-shaped core halves each having two leg portions with end surfaces respectively joined in mutually abutting confrontation with respective gap spacers interposed therebetween at first and second core joint parts and a coil wound around the core joint parts. The coil includes, as an input winding, a primary winding divided into first and second primary windings which are wound at least around the two core joint parts of the core and are connected in parallel. By this arrangement, the magnetic fluxes generated at the two core joint parts cancel each other, and reduce the leakage flux field. Optionally, the two divided windings of the primary winding are each divided further into two windings wound around the leg portions on opposite sides of the spacers. At the same time, the first primary winding on the leg portion on one side and the second primary winding on the other side are connected in series.

Abstract: An improved electric power conversion system comprising a multi-phase bridge circuit composed of semiconductors such as thyristors and an associated firing circuit. It is so constructed that: if the AC input current Iac flowing in the bridge circuit is equal to or larger in value that the DC output current Idc flowing out of the bridge circuit, it will be decided than an inner defect or fault is caused, and possible expansion of inner defect will be prevented by disabling the firing circuit to extinguish the thyristors in the bridge circuit, and if the AC input current Iac is smaller than the DC output current Idc in value, the bridge is permitted to continue the operation of power conversion, thus eliminating unnecessary interruption which otherwise would be caused by exterior disturbances. Also, an improved electric power conversion system may be equipped with a device to prevent an adverse effect from being caused by abnormal rise of thyristors' temperature.

Abstract: A gate pulse generator for a static var compensator (SVC) constituted by a thyristor switched capacitor (TSC) comprises voltage detectors for respectively detecting forward and reverse voltages applied to antiparallel-connected thyristors in the TSC. The antiparallel-connected thyristors comprise a plurality of series-connected forward thyristors and a plurality of series-connected reverse thyristors. The gate pulse generator monitors the forward and reverse voltages and determines whether a period in which both the forward and reverse voltages are zero continues for a predetermined period while reverse-phase sides of the antiparallel-connected thyristors are held in conduction periods, respectively. The gate pulse generator prolongs an active period of a forward conduction period signal by the predetermined period.

Abstract: A multi-stage insulating transformer type high voltage generating apparatus comprising a plurality of magnetic cores interconnected through transmitting coils and receiving coils. The receiving coil of a first one of the magnetic cores is connected to a driver. A plurality of rectifier circuits are connected to the magnetic cores through individual secondary coils, respectively. These rectifier circuits are successively connected in series to provide a high DC voltage. Each magnetic core has a potential fixed equal or close to an output potential of the rectifier circuit of the plurality of rectifier circuits wound therearound which puts out a mean potential. A position betwen the transmitting coil and receiving coil interconnecting adjacent magnetic cores has a potential fixed equal or close to an output potential of a final rectifier circuit provided for a preceding magnetic core.

Abstract: A flyback power supply for use with a cathode-ray tube includes a flyback transformer which comprises a core having two spaced core legs, and two core units supported respectively on the core legs. Each of the coil units includes a low-voltage coil bobbin fitted over one of the core legs, a low-voltage coil wound around the low voltage coil bobbin, a high-voltage coil bobbin disposed around the low-voltage coil bobbin, and a high-voltage coil which comprises a plurality of coil layers wound successively around the high-voltage coil bobbin with insulating layers interposed between the coil layers, the low-voltage coils of the coil units being connected parallel to each other. Diodes are connected in series with the coil layers, respectively of the high-voltage coil of each of the coil units such that voltages produced across the coil layers will be in phase with each other.

Abstract: A high voltage, high power DC power supply includes a single turn primary winding driven through a resonating capacitor by an AC source having a frequency in excess of about 100 kHz. The primary winding includes a pair of concentric cylindrical metal walls having opposite ends electrically connected to each other. A volume between the walls includes plural secondary winding assemblies, having different axial positions along the walls. Each of the assemblies includes an annular magnetic core surrounding the interior wall, a winding on the core and a voltage doubler rectifier. DC voltages developed across each secondary winding assembly by the rectifier are added together to provide the high voltage, high power output. The power supply energizes an X-ray tube having a grounded anode and a cathode at a DC voltage of approximately -150 kV, with a power requirement of between 15 and 60 kW.

Abstract: A high voltage multistage cascade rectifier power supply is provided which maintains uniform potential between the stages of the rectifier, and thus uniformly grades the electric potential, by providing equipotential conductor plates on each side of each stage of the power supply. The plates include both AC and DC plates, with capacitors being provided between each pair of plates defining a stage. Discrete capacitors may be provided between each pair of plates or the plates may form part of the capacitors with dielectric material being provided between the plates. The plates are selectively interconnected by diodes to form the cascade rectifier. Stray capacitance in the cascade rectifier is compensated for with an inductor across the input to the rectifier, which inductor is selected to tune out the stray capacitance. The frequency of the input drive may be automatically adjusted to compensate for changes in the system, including changes in stray capacitance.

Abstract: The invention relates to a measuring and damping resistor arrangement for a high-voltage apparatus. The measuring resistor arrangement preferably includes several series-connected resistors which are arranged on a support and which are capacitively bridged and is electrostatically shielded by a damping resistor arrangement. Preferably, the damping resistor arrangement is formed by a resistance wire wound onto an insulating body which encloses a part of the measuring resistor arrangement at the high-voltage side.

Abstract: An EEPROM constructed in accordance with our invention includes a voltage multiplier for generating an erase voltage and a voltage regulator circuit for controlling the magnitude of the erase voltage. The voltage regulator circuit includes means for providing a first voltage proportional to the erase voltage, means for providing a reference voltage on a reference voltage lead, and means for controlling the voltage multiplier circuit so that if the first voltage is less than the reference voltage, the voltage multiplier circuit will increase the erase voltage, but if the first voltage is greater than the reference voltage, the voltage multiplier will not continue to increase the erase voltage. The voltage multiplier includes novel capacitors and transistors constructed using standard EEPROM processing to withstand high voltages without breaking down.

Abstract: In an electrical device for supplying x-ray tubes, the primary and secondary windings of the transformer are wound on circular coil forms which are adapted to fit within two half-shells. The half-shells are constituted by a recessed annular structure in which capacitors are housed. The output terminals of the secondary windings are placed on one side in order to be connected to the capacitors and to diodes over very short distances.

Abstract: Converter inverters, such as are used in the operation of alternating current machines, have turn-off reverse-conducting GTO thyristors in the bridge arms. Parallel to each GTO thyristor there is provided a series circuit composed of a turn-off load-shedding capacitor with a turn-off load-shedding diode. The common junction points of the respective turn-off load-shedding capacitors and diodes are connected in series to a choke via at least one capacitor load-shedding diode. The inductance of the choke is 2 to 3 times as large as the inductance of the circuit. The reverse-conducting GTO thyristors are directly connected in series, without the series connection of a choke. There thus arises a damping circuit of the GTO thyristor, which is very simple and, at the same time, feed back ring-around energy.

Abstract: A converter circuit includes three-phase unit converters connected in cascade in two stages for supplying electric power to a load. In a region in which the converter output voltage ratio is small, the firing phases of both converters are so set that a phase difference of 120.degree. makes appearance therebetween, while in a region in which the converter output voltage ratio is large, the firing phases are so set as to have a phase difference of 60.degree. therebetween, whereby an angular difference of 90.degree. to 30.degree. is caused to occur constantly between the phases of voltage ripple components of the unit converters. Power factor of a power supply source is improved while ripple in the output voltage of the converter circuit is reduced.

Abstract: With electric valves (7) having several series-connected thyristore (T1 . . . Tn; T1' . . . Tn'), individual thyristors may become defective, so that they do not withstand the blocking voltage applied to them. For the simplified checking of such defects, a process is specified which does not require any individual monitoring on the spot, i.e. for high potential. For this purpose, in the blocked state of the valve (7), all thyristors of one current direction, apart from at least one thyristor being tested, are triggered within a predeterminable triggering interval. If a valve current (i.sub.R) then flows, an indicating and registering device (A1 . . . An) indicates in which thyristor stage the defect has occurred. This status check is preceded by a preliminary test in which it is checked whether all thyristor triggering channels are in order. All thyristors are triggered in this test. If no valve current (i.sub.R) occurs, a triggering channel fault signal (S.sub.U0) is generated.

Abstract: An apparatus for producing a very high DC potential output from an AC input. Multiple secondary circuits, each comprised of an individual coil wound about a separate magnetic core, are positioned within the magnetic field of a single primary coil. The output of each secondary circuit is rectified. The output of all secondary circuits is combined in series to provide the high DC potential. The seconary cores are supplied in parallel from the magnetic flux of the primary coil. The primary core and coil form an essentially cylindrical shell, with the secondary cores and coils located within the cylinder interior.

Abstract: To obtain a ripple-free direct-current focusing voltage in a split-diode technology high-voltage transformer, the tap is made not at the middle point of the second section of the secondary winding but at a point determined by the ratio of the stray capacitances of the two half-windings of this section, and it is directly linked to a high-value resistor.

Abstract: The converter system couples two high voltage three-phase networks. Two converter transformers are associated with each network to be coupled. Each transformer has secondary windings. One secondary winding associated with a first network is Y-connected while the other is delta-connected. The converter transformers operate on a three-phase full wave rectifier with twelve semiconductor rectifier components. The arrangement of valve towers, a stacking of semiconductor components, is designed to keep a base area or a so-called valve housing in which the valve towers are accommodated as small as possible. The semiconductor components are arranged in uniform modular assemblies and may be stacked as modular components having insulating spacings between components which are also uniform. A tower of uniform modules is formed in association with each of the phases of the three-phase secondary windings of the converter transformers. The number of modules defines the number of stories of the tower.

Abstract: A circuit arrangement consists of one or several high voltage transformers and rectifier systems usable advantageously for the step-up transformation of medium frequency voltages, for rectification, and smoothing. With the use of the circuit arrangement according to this invention, systems can be built up having small dimensions and low weight, and usable as high voltage supply units providing low standing wave ratio and good dynamic properties. The secondary winding of the high voltage transformer exhibits a flat arrangement. Electrically connected winding systems are designed from the secondary flat windings (flat windings of a predetermined number are connected in series). The resultant AC voltage of the individual, electrically coupled winding systems is connected to the component rectifiers. The component rectifiers are series-connected on the DC side.

Abstract: In a gate pulse generator for a thyristor converter of the type in which in order to fire thyristors of the thyristor converter in which each arm is comprised of a plurality of series-connected thyristors, the gate pulses are generated in response to the gate command signal and the thyristor forward voltage signal and are converted into the light signals which in turn are transmitted to the thyristor converter, whether or not the forward voltage signal exists when the gate command signal is generated is detected and when the forward voltage signal is generated prior to the generation of the gate command signal, the pulse duration is narrowed to a minimum required for firing the thyristor.

Abstract: An improvement in a commutation control method or a control circuit for a converter comprising a plurality of converter units connected in cascade, which is provided with a circuit which maintains a phase control angle of each converter unit in an about constant angular difference within a range of a specified converter output, thereby enabling precision output control, reduction of the ripple in a delivered current to a load, and an improvement in power factor of an input fundamental wave in comparison with the symmetric control.

Abstract: A transfection high-voltage controller for directing high-voltage currents to a suspension of cells and DNA comprising a control section, a power store, and a high-joule switch. Under control of the control section, the high-joule switch directs a high-voltage current from the power store to a load such as a cuvette. The high-joule switch comprises a semiconductor controlled rectifier (SCR) having a gate coupled to the control unit for triggering the device, an anode for receiving the high-voltage current from the power store, and a cathode for delivering the high-voltage current to the cuvette. A current sink may be connected to the anode of the SCR to render it non-conductive a predetermined time after the high-voltage current appears at the cathode. Multiple SCRs may be connected in series to support voltages over 3,000 and currents in excess of 125 amperes, and a trigger control unit may be attached to the gate of each SCR in the series to effect simultaneous or serial triggering of the group.

Abstract: A fault detector apparatus for a power converter in which a plurality of GTOs, functioning at a predetermined potential, are used. The apparatus includes a first fault-detecting circuit, coupled to the gate-cathode path of one of the GTOs, for generating a first fault signal when this GTO malfunctions, a second fault-detecting circuit, coupled to the gate-cathode path of another one of the GTOs, for generating a second fault signal when this GTO malfunctions, a photocoupler for transmitting a DC-isolated optical signal corresponding to the first fault signal, and one optical fiber system for transmitting a DC-isolated output signal, corresponding to the logical sum of the optical signal transmitted by the photocoupler and the second fault signal, to external circuits set at a potential different from the potential at which the GTOs are arranged. The fault-detecting circuits are provided in the same number as the GTOs. The fault-detecting circuits are coupled by the optical signals.

Abstract: A high voltage DC/DC converter including a voltage resonance switching circuit formed by a coreless transformer, a GTO thyristor switching element connected between the primary winding of the transformer and a D.C. source, and a voltage resonance capacitor connected in parallel to the switching element. A rectifier circuit is connected to the secondary winding of the transformer to rectify an output current from the transformer circuit. The resonance frequency of the parallel resonance circuit made of the resonance capacitor and the coreless transformer is selected to be the frequency of that component of the current supplied to the circuit through the switching element, which has a greater amplitude than any other component of the current (including the fundamental frequency and other harmonic).

Abstract: An electric locomotive has two AC-DC converters which are connected in cascade, and a power factor controller is connected to one of the converters. Two automatic pulse phase shifters are provided for the two converters and controlled by a signal responding to a difference signal between a current flowing in the converters and a reference signal. One of the input signals of the automatic pulse phase shifter is regulated by a bias signal. The output from each of the automatic pulse phase shifters to each of the converters is switched when the measured speed of the locomotive exceeds a predetermined reference speed signal.

Abstract: A high-voltage thristor converter and control therefor includes a plurality of thyristor modules and a transducer for feeding a control signal to each of the thyristor modules in response to an external operation command. The transducer produces an electrical control signal which is directed to a laser beam irradiator which converts the control signal into a laser beam signal. The laser beam signal is directed to a light sensitive element in the thyristor module for converting the laser beam signal into an electric control signal to trigger a thyristor element in the module.

Abstract: A protection circuit for a power converter apparatus is disclosed which is made up of plural unit circuits, each comprising at least one fuse connected in series with a semiconductor element, such as a thyristor, and a non-linear resistor connected in parallel at least with the fuse. In this way fuses can be employed in a power converter apparatus of high voltage and current capacity. The unit circuits can be connected in series or in parallel or both to increase the current and/or voltage capacity of the power converter. Trigger fuses can be employed to halt operation of the unit in the event of fusing of one or more of the fuses.

Abstract: A device for failure detection in series-connected semiconductor rectifiers (1) comprises transformers (2) whose number is equal to that of the rectifiers (1) and which comprise input windings (3), supply windings (6), and additional parallel-connected windings (9), RC-circuits whose number is equal to that of the rectifiers (1), having resistors (4) and capacitors (5), and also a pulse generator (7), and a measuring element (8).The input winding (3) of each transformer (2) has one lead-out thereof connected to a cathode of the respective rectifier (1), and another lead-out to the capacitor (5) of the respective RC-circuit. The resistors (4) of each RC-circuit are connected to the anodes of each rectifier (1). The supply windings (6) of the transformers (2) are connected to one another in series and connected by one terminal to the first lead-out of the pulse generator (7).

Abstract: A power converter including a plurality of serially connected self-turn-off semiconductor elements, including a first control circuit for producing a plurality of control signals, and a plurality of second control circuits is connected to receive respective of the control signals to supply a non-conduction control signal to a respective of the self-turn-off semiconductor elements to turn off the respective semiconductor element. The power converter further includes a plurality of failure detectors and blocking circuits. Each of the failure detectors is connected to a respective of the self-turn-off semiconductor elements for detecting a fault thereof to produce a fault detection signal when the respective self-turn-off semiconductor elements has failed. Each of the blocking circuits is connected to the respective failure detector and to the first control circuit for blocking either the respective control signal or the respective non-conduction control signal based on the respective fault detection signal.

Abstract: The generator comprises a ferromagnetic core (1) having a primary winding (3) and a secondary winding which comprises a number of concentric secondary coils (7A-7F), which are wound with the same winding senses and have substantially the same number of turns and are provided with a layer of insulating material (9A-9E) between every two consecutive coils. The high-voltage portion of the generator is formed by a number of sections (19A, 19B, 19C), each of which comprises at least two series-arranged secondary coils (7A-7F), the number of secondary coils being equal for all sections and the last coil of each section being arranged in series with a rectifier (13A, 13B, 13C). All sections are arranged in series such that the rectifiers have the same forward directions.

Abstract: A high voltage transformer incorporates a bobbin on which the primary winding is wound. The transformer auxiliary coils are wound directly over the primary winding with no intermediate layers of insulation. The wire turns of the auxiliary coils are evenly distributed over the full traverse of the primary winding to improve magnetic coupling and simplify tuning of the transformer.

Abstract: A protection circuit for use with a thyristor having several break over diode, BOD, elements is connected between the anode and the gate of a thyristor providing static and dynamic overvoltage protection. With the exception of the BOD element connected to the gate, all the BOD elements have RC circuits connected in parallel, whose respective resistance and capacitance values are essentially identical. The BOD element connected to the gate and the cathode-gate portion of the thyristor has an additional RC circuit connected in parallel, whose resistance value is smaller or the same and whose capacitance value is smaller than the respective resistance and capacity values of the other RC circuits. Preferably, in this last RC circuit the resistance value is very small in contrast to the resistance values of the other RC circuits, and the capacitance value is negligible.

Abstract: A flyback transformer includes a bobbin and first and second holders mounted on the bobbin in a predetermined spaced relationship with each other, for holding a circuit element such as a diode. The first holder has a first surface facing the second holder and a first step formed between the first surface and the bobbin. Similarly, the second holder has a second surface facing the first holder and a second step formed between the second surface and the bobbin. Thus, the element is pressure fitted between the first and second surfaces with the opposite ends of the element being seated on the first and second steps.

Abstract: An apparatus for controlling a thyristor converter includes a plurality of voltage detectors provided for individual series-connected thyristors respectively for detecting the presence or absence of voltage applied to the thyristors, and elements for generating a thyristor triggering pulse signal representative of the logical sum of the voltage presence-absence signals from the voltage detectors and a triggering command signal commanding the desired triggering phase and on-period of the thyristor converter. The apparatus comprises a plurality of differentiation circuits differentiating the output signals of the plural voltage detectors respectively, and a signal synthesis circuit synthesizing the output signals of the differentiation circuits to generate an output signal indicative of the voltage presence or absence. By virtue of the above construction, the thyristor converter can continuously operate without being shut down even when any one of the thyristor voltage detection signals is disabled.

Abstract: The invention is a method and a circuit for the emergency firing of individual thyristors in a thyristor valve that have a protection circuit for providing an emergency gate control signal for firing the thyristor when the voltage applied thereto equals or exceeds a predetermined initial emergency voltage triggering level. In operation a thyristor is initially fired using the emergency gate control signal produced by the protection circuit when the voltage applied thereto equals or exceeds the emergency voltage triggering level. The emergency voltage triggering level is then reduced. The subsequent firing of the thyristor by the protection circuit occurs when the applied voltage equals or exceeds the reduced emergency voltage triggering level. This allows both economy of operating conditions and protection of the individual thyristor and its associated snubber circuit during prolonged emergency firing conditions.

Abstract: A gate-turn-off thyristor failure detecting circuit includes a detector which detects an off-gate signal for a gate-turn-off thyristor and a current level detector which compares the signal with a predetermined value and produces an output signal indicative of the failure of the gate-turn-off thyristor.

Abstract: A secondary winding, divided into a plurality of sections, is provided around a primary winding of the air-core type. First and second diode groups are disposed on four substrates which surround the secondary winding. Diodes in each of the first and second diode groups are disposed on two adjacent substrates so that these diodes are connected in series so as to have the same polarity direction, respectively. The first and second diode groups are respectively divided into a plurality of diode sections. Winding start ends and winding finish ends of winding sections are coupled between the respective two adjacent diode sections. The diode sections disposed on the each substrate are arranged to be spaced apart along the axial direction of the primary winding. One of the diode sections to which induced voltages of the winding sections are applied is disposed on two adjacent substrates, and the other diode section is disposed on the other two adjacent substrates.

Abstract: A high voltage thyristor valve of the air insulation type erected upright on a valve hall is disclosed, which comprises a thyristor valve body erected in the valve hall and a plurality of reinforcing means stretched between the thyristor valve body and inner walls of the valve hall, each of the reinforcing means including a wire rope and an insulator.

Abstract: A high voltage semiconductor valve has a plurality of electrically series-connected semiconductor elements, for example thyristors or diodes. These are designed for pressure contact connection and for double-sided cooling and are arranged alternately with liquid cooling bodies in a stack. At least some of the resistors included in the voltage divider of the valve are arranged with their resistive portions located in a passage in the cooling body between the contact surfaces for the two adjacent semiconductor elements.

Abstract: A device is taught for controlling the residual charge on a thyristor switched capacitor. A capacitor is in series circuit relationship with at least two bidirectional back-to-back thyristor switches which are then connected across an AC network. Each back-to-back thyristor combination is shunted by a non-linear clamping device which exhibits a very high resistance below a specified voltage level and a very low resistance above that voltage level. A pulse stretcher and a sequential firing circuit arrangement is used to prolong the conduction of one of the thyristor switches at a time to allow the shunting of its associated clamping device. During an overvoltage condition in the AC network, the residual charge on the capacitor will be limited to the breakdown voltage of the conducting clamping device. A plurality of capacitor, thyristor switch, non-linear clamping device combinations may be utilized in parallel with the AC network.

Abstract: A compact high voltage power supply includes a high voltage transformer 4 with individual concentric secondaries S1, S2, . . . , connected to form a ladder network with two series-connected assemblies of diode rectifiers R and R' respectively located on corresponding sides of the transformer winding. Next-adjacent secondaries S1, S2, . . . , are wound from the same side of the winding space but in an opposite winding sense, and each secondary comprises an odd plurality of layers. This provides a high voltage transformer arrangement without cross-connection of the diodes in which the peak and alternating voltages across the interwinding insulation is optimally reduced and the smoothing effect of stray capacitances is enhanced.

Abstract: A circuit for applying unidirectional pulses to a precipitator, in addition to a base d.c. level supplied by a transformer/rectifier set, includes a rectifier, an inverter and a transformer/rectifier set connected to charge a storage capacitor. Discharge of the capacitor into the precipitator is controlled by a chain of unidirectionally conducting devices (thyristors as shown) which are simultaneously triggered at the desired voltage at the capacitor. In other embodiments breakover diodes are used instead of the thyristors.

Abstract: A power converter utilizes first and second thyristor bridges energized by two AC power sources which are insulated from each other. The power converter includes first and second auxiliary thyristor circuits each containing plural thyristors, and a commutation circuit. The cathode of each thyristor of first auxiliary thyristor circuit is connected to one of the AC power sources, and the anode of respective thyristors are connected each other at a common node. The anode of each thyristor of second auxiliary thyristor circuit is connected to the other of the AC power sources, and the cathode of respective thyristors are connected each other at another common node. The commutation circuit is connected between the common nodes of the first and second auxiliary thyristor circuits.

Abstract: In order to increase the resonance frequency of a transformer, the secondary winding is divided into several (identical) coils, which are each connected to a corresponding individual bridge rectifier circuit. The outputs of the bridge rectifier circuits are connected in series and each coil is wound in a sense opposite to that of the immediately adjacent coil(s). Each coil is divided into two series-connected sections which are each wound in a corresponding individual winding compartment of the coil former. The series connection between the two coil sections extends through a passage at the bottom of the partition wall between the two winding compartments. Consequently, the coil ends are located on the outerside of each coil section so that it is possible to provide a simple connection with short connecting leads.