A method for generating/transmitting a transmission-unit symbol sequence is disclosed. In the case of transmission information, the information is modulated in time and frequency domains on the basis of a predetermined transmission unit (e.g., a transmission time interval TTI or slot), simultaneous transmission of the information is made, and then a transmission unit symbol is generated/transmitted. A transmission sequence is masked in each symbol contained in one transmission unit. Symbol-unit circular shift (cyclic shift) is applied to the masked result, so that transmission efficiency increases. A control signal transmission method for supporting a variety of formats and a signal transmission method based on a prime-length sequence are also provided.

A communications transmitter includes a baseband processor configured to generate amplitude, angle, in-phase and quadrature baseband signals and a combination modulator that is configurable to modulate in the polar domain and, alternatively, in the quadrature domain. The combination modulator includes a quadrature modulator and a separate and distinct angle modulator that is configured to serve as a local oscillator for the quadrature modulator. In one embodiment of the invention the combination modulator is configured to modulate in the quadrature domain when the transmitter is operating according to a first communications condition (e.g., first transmit power level or first modulation scheme) and is configured to modulate in the polar domain when the transmitter is operating according to a second communications condition (e.g., second transmit power level or second modulation scheme).

A device for mixing multiple (N) pulse density modulated (PDM) bit streams of a bit rate, the device comprises an input logic, an error accumulation circuit, an error correction circuit and an adder of more than N bits; wherein the device is arranged to output an output PDM bit stream that represents a mixture of the multiple input PDM bit streams; wherein the output PDM bit stream comprises a plurality of output PDM bits, wherein a certain output PDM bit of a plurality of output PDM bits that form the output PDM bit stream is generated during a certain clock cycle; wherein the input logic is arranged to select, during each fraction of the certain clock cycle, a current bit of a selected PDM bit stream, wherein different PDM bit streams are selected during different fragments of the certain clock cycle; wherein the error accumulation circuit is arranged to store intermediate values during a first fraction till a penultimate fraction of the certain clock signal and to store a last value during a last fraction of the certain clock signal.

The present invention relates to a switched-mode power supply apparatus and a corresponding method. For an effective compensation of non-linearities caused by dead-time and voltage drops in the switching power amplifier of the apparatus, an apparatus is proposed comprising a switching power amplifier (14) for amplifying a signal supplied by an external signal source (11) and for supplying a load voltage and/or load current to a load (15), and a control unit (12; 12b) for controlling the switching of said switching power amplifier based on a timing setting, said control unit being adapted for simulating the behavior of the switching power amplifier by predicting the average load voltage and/or load current for at least two, in particular a plurality of, timing settings for a desired load voltage and/or load current based on state information about the present state of the switching power amplifier.

A frequency modulating path for generating a frequency modulated clock includes a direct feed input arranged for directly modulating frequency of an oscillator, and a compensating feed input arranged for compensating effects of frequency modulating on a phase error; wherein the compensating feed input is resampled by a down-divided clock that is an integer edge division of the oscillator. A reference phase generator for generating a reference phase output includes a resampling circuit, an accumulator and a sampler. The resampling circuit is for resampling a modulating frequency command word (FCW) input to produce a plurality of samples. The accumulator is for accumulating the samples to generate an accumulated result. The sampler is for sampling the accumulated result according to a frequency reference clock, and accordingly generating a sampled result, wherein the reference phase output is updated according to at least the sampled result.

Provided is a method for transmitting data in a communication or broadcasting system using a linear block code by generating a codeword by encoding input information data bits, interleaving the codeword; outputting modulation signal-constituting bits by bit-mapping the interleaved codeword using a bit-mapping table predetermined depending on a modulation scheme and a coding rate, outputting a modulation signal by modulating the modulation signal-constituting bits and transmitting the modulation signal via a transmit antenna.

A frequency modulator includes a digitally-controlled oscillator (DCO) arranged for producing a frequency deviation in response to a modulation tuning word and a phase-locked loop (PLL) tuning word. In addition, another frequency modulator includes a DCO and a DCO interface circuit. The DCO is arranged for producing a frequency deviation in response to an integer tuning word and a fractional tuning word. The DCO interface circuit is arranged for generating the integer tuning word and the fractional tuning word to the DCO, wherein the fractional tuning word is obtained through asynchronous sampling of a fixed-point tuning word.

Embodiments of digital high-speed bi-phase modulator and method for bi-phase modulation are generally described herein. In some embodiments, the digital high-speed bi-phase modulator comprises a high-speed digital divider, a high-speed digital multiplexer, and matched signal paths provided between the divider and the multiplexer. The high-speed digital divider is configured to receive a carrier signal and generate complementary output signals. The high-speed digital multiplexer is configured to switch between the complementary output signals and generate a bi-phase modulated output at a carrier frequency (fc) modulated with a bi-phase code. The bi-phase code may be provided to control inputs of the multiplexer.

An apparatus for coding a signal by means of amplitude shift keying comprises a class E amplifier including a switching transistor, to whose gate is supplied a voltage having an operating frequency for operating the class E amplifier. For achieving an amplitude shift keying in the output signal of the class E amplifier, a circuit for switching the operating frequency of the voltage supplied to the gate of the switching transistor, or the resonance frequency of the class E amplifier, between a first value and a second value is provided and in order to switch a deviation degree between the operating frequency and the resonance frequency between a first value and a second value.

A modulation apparatus for a class D switching amplifier is capable of reducing power consumption of an Electro-Migration Interface (EMI) of an output end and a gate driver end in a zero input signal. The modulation apparatus for a class D switching amplifier includes a control unit for detecting and outputting a control signal which is a common signal component of a first modulation signal modulated by using a first input signal and a second modulation signal modulated by using a second input signal; and is characterized by feedback of a first output signal, a second output signal and a common output signal outputted by using the first modulation signal, the second modulation signal and the control signal through an input of the modulation apparatus.

In a method of transmitting a data stream from a transmitter in a multiple-input-multiple-output (MIMO) wireless communication system, where the transmitter comprises a plurality of transmit antennas, a discrete Fourier transform (DFT) is applied to the data stream to generate a plurality of symbol sequences; symbols of a first symbol sequence from the plurality of symbol sequences are paired with symbols of a second symbol sequence from the plurality of symbol sequences to generate a plurality of symbol pairs, wherein the pairing results in an orphan symbol; a space-time block code (STBC) is applied to the symbol pairs to generate a plurality of sets of STBC symbols, each set of STBC symbols being associated with a corresponding one of the plurality of antennas; a cyclic delay diversity (CDD) operation is applied to the orphan symbol to generate a plurality of CDD symbols, each CDD symbol being associated with a corresponding one of the plurality of antennas; and each one of the antennas transmits the corresponding set of STBC symbols and the corresponding CDD symbol.

The present invention relates to a digital modulation method and a corresponding modulator. The modulator comprises a transcoder (110) followed by a FIFO register (120) and a 2-PSK modulator (130). The transcoder codes a binary word of fixed size into a code word of variable size using a transcoding table. The transcoding table codes at least one first binary word, leading to a first number of phase transitions at the output of the modulator, into a second word of size greater than that of the first word, leading to, at the output of the modulator, a second number of phase transitions less than the first number of phase transitions.

The present invention provides a digitally controlled, current starved, pulse width modulator (PWM). In the PWM of the present invention, the amount of current from the voltage source to the ring oscillator is controlled by the proposed header circuit. By changing the header current, the pulse width of the switching signal generated at the output of the ring oscillator is dynamically controlled, where the duty cycle can vary between 50% and 90%. A duty cycle to voltage converter is used to ensure the accuracy of the system under process, voltage, and temperature (PVT) variations. The proposed pulse width modulator is appropriate for dynamic voltage scaling systems due to the small on-chip area and high accuracy under process, voltage, and temperature variations.

Systems and methods for operating with oscillators configured to produce an oscillating signal having an arbitrary frequency are described. The frequency of the oscillating signal may be shifted to remove its arbitrary nature by application of multiple tuning signals or values to the oscillator. Alternatively, the arbitrary frequency may be accommodated by adjusting operation one or more components of a circuit receiving the oscillating signal.

A memristor-based emulator including a memristor circuit for use in digital modulation that includes a first current feedback operational amplifier (CFOA) having multiple terminals in communication with a capacitor Cd and in further communication with a resistor Ri. A second CFOA having multiple terminals is in communication with the first CFOA and is adapted to be in further communication with a voltage vM to provide an input current iM for integration by a capacitor Ci. A nonlinear resistor is in communication with the second CFOA. A third CFOA having multiple terminals is in communication with the nonlinear resistor and is in further communication with the first CFOA and a resistor Rd. The third CFOA and the resistor Rd act as an inverting amplifier associated with the nonlinear resistor to increase a current gain to increase a difference between ON and OFF values of a resistance of a realized memristor.

A method for phase modulation of a carrier signal from a transmitter to a contactless transponder in which data is coded as consecutive symbols, each corresponding to a predefined number of carrier cycles, and in which a symbol time is at least two cycles of the carrier signal includes, at the transmitter, spreading a phase jump of a symbol in relation to a preceding symbol over a first part of the symbol time. The establishment of the phase jump is completed in the first part of the symbol time. The periods of the cycles are constant during a second part of the symbol time.

A PWM signal generating circuit, printer, and PWM signal generating method are described. The PWM signal generating circuit includes: a single counter configured to count values expressed in N bits; and at least one arithmetic device configured to generate a PWM signal, each of the at least one arithmetic device including a pulse width data storage unit for storing N-bit pulse width data representing a pulse width of the PWM signal to be generated, and an adder for calculating a carry value from a most significant bit obtained when adding the count value and the pulse width data. A signal having a level corresponding to the carry value is output at every change in the count value so that the PWM signal having the pulse width of the pulse width data is generated.

A modulator which has a first terminal to receive a carrier signal, a second terminal to receive a first control signal to control a frequency band of the carrier signal and a third terminal to receive a second control signal to control a modulation depth of the carrier signal.

A circuit breaker is provided which can be filled with a quenching gas and which has two contact arrangements, which can be moved relative to one another and along a longitudinal axis of the circuit breaker. The contact arrangements form a arcing contact system and a rated current contact system connected electrically in parallel with it. One of the contact arrangements includes inner rated current contacts and outer rated current contacts of the rated current contact system, where the inner rated current contacts overhang the outer rated current contacts in the direction of the longitudinal axis, and the outer rated current contacts coaxially surround the inner rated current contacts. The circuit breaker has a high current carrying capability as well as a reliable switching-on and -off behavior, such as during and after the occurrence of a short-circuit current in the circuit breaker.

To provide an electric current switching apparatus having a fixed-side electrode unit and a movable-side electrode unit that are arranged to align central axes thereof with each other and to face each other, in which a movable contact provided in the movable-side electrode unit reciprocates on the central axis to contact or separate from a fixed-side contact provided in the fixed-side electrode unit, thereby switching electric current flowing through these electrode units, the electric current switching apparatus including a plurality of permanent magnets that are provided in at least one of the fixed-side electrode unit and the movable-side electrode unit, that have bodies arranged on the central axis to align magnetizing directions thereof with the central axis, and that are arranged to cause same poles of adjacent ones of the permanent magnets to face each other as if butting with each other.

This disclosure relates to methods and systems to reduce high voltage breakdown jitters in liquid dielectric switches. In particular, dielectric liquids have been produced that contain a suspension of nanoparticles and a surfactant to reduce the breakdown jitter. In one embodiment, the suspended nanoparticles are Barium Strontium Titanate (BST) nanoparticles.

An electromagnetic actuator comprising a core moving between a latched position and an open position, a permanent magnet, a coil designed to generate a first magnetic control flux to move the core from an open position to a latched position, and a second magnetic control flux designed to facilitate movement of the moving core from the latched position to the open position. The permanent magnet is positioned on the moving core so as to be at least partly outside the fixed magnetic circuit in which the first magnetic control flux flows in the open position, and to be at least partly inside the fixed magnetic circuit used for flow of a magnetic polarization flux of the magnet in the latched position.

A spout assembly is provided. The spout assembly includes a spout and a spout base. The spout base has a cross-sectional area that is smaller than a spout sized to enclose an electrical switching apparatus electrical coupling. That is, the spout base includes a CT support surface with a cross-sectional area that is smaller than the spout cross-sectional area. Current transformers are disposed upon the spout base CT support surface.

Disclosed is a switchgear including: a vacuum chamber; a fixed electrode having a fixed contact at an end thereof, the fixed contact being disposed within the vacuum chamber; a movable electrode having a movable contact at an end thereof, the movable contact being disposed within the vacuum chamber; a linkage assembly electrically connecting or disconnecting the movable electrode and the fixed electrode; an engaging coil spring; and a disengaging coil spring. The engaging coil spring and the disengaging coil spring are provided such that centers of the diametric directions thereof are substantially coaxial and at least a part of the engaging coil spring and a part of the disengaging coil spring overlap each other.

A switch suitable for DC applications includes: two fixed conductive contacts with first contact areas; a movable conductive bridge with two second contact areas for being connected to the two first contact areas in the on-status and for being disconnected from the two the first contact areas in the off-status; and two arc-extinguishing units configured to extinguish electric arcs occurring between the first and second contact areas after disconnecting the second contact areas from the first contact areas. First conductive arc-guiding elements extend from each first contact area into the corresponding arc-extinguishing unit and at least one second conductive arc-guiding element extends into the arc-extinguishing units suitably shaped to guide the electric arcs from each of the second contact areas of the movable bridge into the arc-extinguishing units.

In an electrical distribution cabinet a mechanism providing quick, reliable, passive arc blast control has a flue chamber surrounding the likely arc site such as an electrical connection point. The flue chamber provides a flue channel which lengthens the arc and attenuates the current and temperature until the arc is extinguished. Preferably, the flue chamber and channel are formed of opposable open-faced polyhedral structures, one fitting inside the other. The mechanism is particularly suited for draw-out circuit breaker connections in a switch gear cabinet.

A driver for a switch in a GIS (Gas Insulation Switchgear) includes a motor, a shaft connected with a moving contact of the switch, a gear connected with one terminal of the shaft and configured to transfer power of the motor to cause the shaft to reciprocate the moving contact through the shaft, a cam spline combined with the shaft and spaced apart from the gear, and a micro-switch connected with the cam spline and configured to control an operation of the motor.

A method of manufacturing a power contactor from an existing contactor having a magnetic amplifier that comprises a blowout coil and a ferromagnetic core, and an arc chute for extinguishing an arc generated by opening the existing contactor under a current load is disclosed. The method includes removing a bolt assembly from the existing contactor and at least one side plate from the existing contactor. The method also includes removing the ferromagnetic core from the existing contactor.

A three-phase disconnect switch for a power distribution system that supplies three-phase power from a source through a main circuit breaker to multiple three-phase feeder circuits, includes three pairs of contacts adapted for connection to the three phase lines of a selected one of the feeder circuits for opening and closing each of the phase lines, and a movable actuator associated with the three pairs of contacts and responsive to a signal indicating the occurrence of an arcing fault in the selected feeder circuit for initially creating a short circuit across the three phase lines of the feeder circuit and then opening the contacts.

The invention relates to a medium voltage switchgear assembly which comprises at least one disconnector and whose drive unit is disposed inside or outside a gas chamber according to the generic part of claim 1. In order to further develop a switchgear assembly of the generic type so as to render the same more compact and more functional, the disconnector is embodied as a three-position vacuum chamber switch.

A switching apparatus includes: a vacuum valve which houses a fixed side electrode fixed to a fixed current-carrying shaft and a movable side electrode fixed to a movable current-carrying shaft coaxially arranged with the fixed current-carrying shaft in face-to-face relation to the fixed side electrode; and a buffering mechanism which is coaxially disposed with the fixed current-carrying shaft on the fixed side of the vacuum valve and reduces a collision load at the time when the movable side electrode is close contact with the fixed side electrode.

The present invention relates to contactors for unidirectional DC operation with permanent magnetic arc extinguishing. In addition to the blow magnets, the contactors are equipped with compensatory permanent magnets for compensating the magnetic field in the vicinity of the contact bridge in order to prevent contact levitation, i.e., an uncontrolled opening of the contacts that is due to a magnetic force generated by a strong current flowing through the contact bridge. To this end, the compensatory permanent magnets are arranged in the vicinity of the contact bridge and polarized in the opposite direction of the blow magnets. The magnetic field of the compensatory magnets and the current flowing through the contact bridge are generating a magnetic force that acts on the contact bridge and tends to keep the electrical contacts closed.

The switchgear includes a vacuum circuit breaker that is disposed in a circuit breaker chamber compartmented by a grounded metal plate, a busbar that is disposed in a busbar chamber and connected to the vacuum circuit breaker through a conductor, a cable that is disposed in a cable chamber and connected at one end to a load side, and a grounding device that is operated by a grounding device actuator disposed in a grounding device actuator chamber, connected to the vacuum circuit breaker through a conductor, and connected to the other end of the cable. The busbar is formed by a solid-insulated busbar. The conductor connecting the vacuum circuit breaker to the busbar and the conductor connecting the vacuum circuit breaker to the grounding device are both formed by a solid-insulated conductor. The circuit breaker chamber and the grounding device have a sealed structure.

An arc runner assembly for use in a circuit interrupter provides a pair of arc runners that are situated at opposite sides of a stationary contact of the circuit interrupter. If used in a DC application, the arc runner assembly is configured to communicate a positive DC arc along one of the arc runners in a first direction away from the stationary contact and is further configured to communicate a negative DC arc along the other arc runner in another direction away from the stationary contact. The arc runner assembly additionally includes a support that is electrically engaged with a conductor of the circuit interrupter on a surface opposite that on which the stationary contact is disposed. The improved arc runner assembly advantageously facilitates extinction of electrical arc and extinguishes both positive and negative DC arcs in a DC application.

An electric switch for application to high- and very high-voltage circuit breakers and switches comprising a flexible toroidal helical spring (8) placed in a groove of a control rod (1) carrying a movable resistance-insertion contact (2), and springs (4) placed about the movable resistance-insertion contact to cause the springs to be compressed until a certain value is reached, at which value the movable resistance-insertion contact causes the flexible toroidal helical spring (8) to deform under pressure enabling the movable resistance-insertion contact (2) to be withdrawn. Among other uses, the switch is suitable for use in a resistance-inserting device that does not need additional mechanical moving parts. For application to high- and very high-voltage circuit breakers and switches.

A circuit interrupter includes, a first contact and a second contact, the second contact being moveable relative to the first contact, a drive assembly structured to move the second contact relative to the first contact, and an erosion monitoring device including a linear transducer coupled to a portion of the drive assembly. The liner transducer is structured to generate an output signal representative of an amount of linear displacement of the portion of the drive assembly, wherein the erosion monitoring device is structured to monitor a degree of erosion of at least one of the first contact and the second contact based on the output signal.

A gas circuit breaker comprising: a sealed tank; two breaking sections disposed in the sealed tank; a bracket to support movable parts of the breaking sections while enabling switching operation of the movable parts; an insulation cylinder to support the bracket through an electric field relaxation shield; an insulated operating rod disposed in the insulation cylinder movably in the axial direction and an end thereof is connected to an actuator; and a link mechanism connected to other end of the insulated rod and transmits drive force from the actuator to the movable parts of the breaking sections, wherein the electric field relaxation shield is provided with out-side groove and in-side groove on the insulation cylinder respectively, and the out-side groove and in-side groove are formed openings at the link mechanism side respectively, and end of the in-side groove is extended to near the outer surrounding of the insulated operating rod.

A sealed solenoid, magnetically operated electric power switch is suitable for use as capacitor, line and load switch operating at transmission and distribution voltages that includes no dynamically moving seals through the sealed container housing the contactor portion of the switch. The sealed solenoid switch includes a magnetically operated drive system with an actuator that magnetically couples across the container wall to avoid the use of a moving or sliding seal as part of the drive system. The sealed solenoid switch may also include a ballast resistor and resistor contact located inside the sealed container to avoid another seal as part of the ballast system. A magnetic latch holds the switch in a closed position, and a spring holds the switch in the closed position, to avoid the need for an energizing current to maintain the switch in either position.

In a vacuum circuit breaker corresponding to three-phase, which is configured by linearly arranging three pressure tanks respectively corresponding to one-phase, in which insulation gas is encapsulated, and a vacuum valve is installed, each pressure tank has a nearly longitudinal shape or a nearly square shape, viewed from a plane surface, and the vacuum valve is arranged in each of the pressure tanks in a state where a drive direction of the movable conductor is aligned with an upper lower direction, and the movable conductor is positioned lower than the vacuum valve, and keeps a sufficient insulation distance with respect to the movable-side connection conductor, and is neared to a position in one of diagonal directions or longitudinal directions of the pressure tank having a nearly square shape or nearly ellipsoidal shape, and moreover, the operation mechanism is arranged and configured at a position, which is lower than the vacuum valve.

A gas circuit breaker includes movable and fixed electrode parts arranged to face each other in an engaging/separating manner in a container filled with an insulating gas, an operating mechanism attached to a partition of the container and configured to output an operating force to the movable electrode part, an operating rod attached to the movable electrode part, a first link rotatably attached to the operating rod, a lever rotatably attached to the first link, a support bearing fixed to the partition of the container via an insulating spacer, a second link rotatably attached to the lever and also rotatably attached to the support bearing, a seal bearing connected through the partition of the container, a seal rod rotatably attached to the center of the lever and slidably supported to the seal bearing, and a third link rotatably attached to the seal rod and also attached to the operating mechanism.

A switch unit includes a plurality of switches, which are linearly disposed. The movable electrode in one switch and the fixed electrode in another switch are electrically connected to each other.

An arc chamber for a circuit breaker has first and second mounting bodies. The mounting bodies are disposed at the ends of an electrically insulating insulation section of the arc chamber. The insulation section is formed of at least two shell-shaped partial sections. The partial sections are curved concavely relative to a longitudinal axis of the arc chamber. A gap is formed between the edges of the bodies of the partial sections.

A circuit protection device is provided for use with a circuit that includes at least one pair of conductors. The protection device is configured to generate an arc. The protection device includes at least a pair of electrode assemblies electrically coupled to the at least one pair of conductors and a conductor base to support the pair of electrode assemblies. The protection device includes a cover coupled to the conductor base and defining at least one isolation chamber, wherein the electrode assemblies are disposed within the isolation chamber. The protection device includes a containment shield moveably coupled to the cover. The containment shield defines a containment chamber configured to contain charged particles produced by the arc. The containment shield is operative to move relative to the cover in response to a change in pressure produced by the arc within the containment chamber. An isolation assembly is coupled to at least one of the cover and the containment shield and configured to prevent the cover from contacting the containment shield.

A guide assembly for a switchgear assembly is provided. The guide assembly includes an elongated support member and a passage. The support member is coupled to and extends from a housing assembly rear sidewall. The support member extends in the circuit breaker assembly direction of travel. The passage is disposed on the circuit breaker assembly base and also extends in the circuit breaker assembly direction of travel. The support member is substantially aligned with the passage. In this configuration, as the circuit breaker assembly moves between a withdrawn position and an installed position, the support member moves between a first position, wherein the support member is not disposed in the passage, and a second position, wherein the support member is partially disposed in the passage. When the support member is in the second position, the support member bears a portion of the weight of the circuit breaker assembly base.

Provided is a sector gear including: a drive gear having a drive part that forms a part of a circle and has a plurality of teeth and a non-drive part that forms a remaining part of the circle and provides a non-contact angle of at least approximately 90 degrees; first and second movers forming a disconnector and a grounded breaking switch, respectively; and first and second driven gears engaged with the drive gear and respectively engaged with the first and second movers and configured to make the first mover or the second mover operate in conjunction with the drive part of the drive gear according to a direction of rotation of the drive gear, wherein an intermediate angle between the first and second movers is between approximately 90-135 degrees. The present invention can reduce the size of the gas-insulated switchgear having the sector gear.

Equipment protection systems, arc containment devices, and methods of assembling arc containment devices are disclosed. In one example, an electrical isolation structure includes a conductor base, a cover coupled to the conductor base and defining an isolation chamber, a containment shield disposed on the conductor base within the isolation chamber, and a biasing assembly positioned between the cover and the containment shield. The containment shield defines a containment chamber configured to enclose the plurality of electrode assemblies. The containment shield is configured to at least partially contain the arc products within the containment chamber. The biasing assembly is configured to permit the containment shield to move away from the conductor base to thereby define a gap between the conductor base and the containment shield to enable at least some of the arc gases to vent from the containment chamber.

An electrode assembly for a circuit breaker is provided. The electrode assembly includes a conductive assembly and a heat transfer assembly. The conductive assembly includes a stem portion and a contact portion. The heat transfer assembly includes a number of elongated bodies, a first heat transfer surface, and a second heat transfer surface. The first heat transfer surface is disposed on the conductive assembly. Each heat transfer assembly body includes a second heat transfer surface. Each heat transfer assembly body is coupled to the conductive assembly with the first heat transfer surface coupled to a number of second heat transfer surfaces.

A gas insulated switchgear includes an enclosure, a first fixed conductor, one side of the first fixed conductor being bent at a right angle and another side of the first fixed conductor being fixed on one side of the enclosure, a second fixed conductor configured to be spaced apart from the first fixed conductor and configured to be fixed on another side of the enclosure, a screw configured to form an axis on inner of the enclosure and being spaced apart from the first and second fixed conductors and a movable conductor configured to move along the axis through a rotation of the screw, one side of the movable conductor being in contact with the second fixed conductor.

A gas circuit breaker is provided, avoiding change in the position of a cover member and without weakening of the blow of gas to the arc in an arc discharge cavity even when a surface of the cover member in contact with the arc discharge cavity is damaged. The gas circuit breaker includes a contact ring, a holder attached to the contact ring, and extending to a path of arc-extinguishing gas that extinguishes an arc, and an electrically insulative cover member attached to the holder.

A flexible shunt for a vacuum circuit breaker can have a reduced straight length and improved flexibility even with an increased thickness within a predetermined accommodation space of a main circuit part. The flexible shunt comprises a pair of conductive plates, each including a clamp connecting portion configured as a flat conductive member, the clamp connecting portion being connected the clamp, a terminal side connecting portion configured as a flat conductive member, the terminal side connecting portion being connected to the terminal side, and a flexible curved portion configured to connect the clamp connecting portion to the terminal side connecting portion, the flexible curved portion being formed to be projected outwardly.