Abstract: A multilevel inverter using a cascade configuration with a device for equally controlling a power factor for each unit cell includes: a master controller, a plurality of power cells connected in series for each of three AC (Alternating Current) phases, a phase shift transformer for supplying a power cell input voltage, a CAN (Controller Area Network) communication network to provide a communication path between the master controller and each power cell, and cell controllers to control output voltages and output frequencies of the respective power cells according to a voltage command and a frequency command from the master controller, each cell controller having a pulse width modulator to generate a pulse width modulation control signal of a variable voltage and a variable frequency to the connected corresponding power cell, wherein each cell controller is configured to calculate a phase difference value of the corresponding power cell according to a preset total number of connected power cells and the floor n

Abstract: A data relay apparatus for communication module is disclosed, whereby a plurality of normally operative communication modules can perform data communication thereamong by allowing a data relay unit to relay data received by an input/output (I/O) port of an inoperative communication module in a case there is available an inoperative communication module among the plurality of communication modules, in a network configured by connecting the plurality of communication modules having two I/O Ethernet communication ports connected via a line topology.

Abstract: Disclosed is an instrument transformer detecting an amount of power supplied to a load via a high voltage line, wherein the instrument transformer is integrally configured with a current level converter, a voltage level converter and a power amount calculating module so that it detects an amount of power supplied via the high voltage line and transmits the detected amount of power to a power amount management unit as a digital signal to correctly detect the amount of power.

Abstract: Disclosed is an apparatus for indicating a closing operable state for an air circuit breaker and an air circuit breaker having the same. The apparatus for indicating a closing operable state for the air circuit breaker comprises a micro switch installed at a switching mechanism providing a driving force for switching contactors, provided with a lever extended into the switching mechanism so as to receive the driving force, generating and outputting an electric signal for indicating that the air circuit breaker is in a closing operable state, and provided with a signal transmitting terminal for transmitting the electric signal to a remote place, and an on coupling pressing the lever of the micro switch so that the micro switch generates and outputs the electric signal only when a closing spring for providing elastic energy for switching the contactors charges elastic energy and the air circuit breaker is opened.

Abstract: Disclosed is a frame for a circuit breaker, including: a plurality of unit frames having a plurality of inner spaces, and a connection unit coupled between two adjacent unit frames among the unit frames and connecting the two unit frames to each other, thereby reducing the manufacturing cost as well as facilitating its manufacture and reducing the manufacturing time.

Abstract: Provided are an air circuit breaker capable of allowing a closing spring to be automatically discharged at a pulled-out position in a pull-out type air circuit breaker and an automatic discharging apparatus for the closing spring in the air circuit breaker, the automatic discharging apparatus for the closing spring comprising a cam shaft rotation preventing unit installed on a cam shaft allowing the closing spring to be charged or discharged and configured to restrict the rotation of the cam shaft by an elastic restoring force of the closing spring, and a unit for releasing the cam shaft rotation preventing unit connected to the cam shaft rotation preventing unit and configured to allow the cam shaft to be rotated by the elastic restoring force of the closing spring according to positions where a main body of the air circuit breaker is pulled out of a cradle.

Abstract: An apparatus for auxiliary contact of circuit breaker is disclosed that is capable of preventing an erroneous operation of and damage to an ON/OFF switch caused by over-stroke of a linkage mounted at an auxiliary contact apparatus, and enhancing reliability despite repeated opening/closing thereof.

Abstract: A sealed cased magnetic switch includes: a first contact pressure spring having one end supported by the movable contactor and applying an elastic force to the movable contactor to provide a contact pressure in a direction in which the movable contactor is brought into contact with the fixed electrode; a spring seat member supporting the other end of the first contact pressure spring and fixedly installed on the driving shaft; and a second contact pressure spring having a diameter larger than that of the first contact pressure spring and applying an elastic force at an outer position in a radial direction compared with the first contact pressure spring to the movable contactor in a direction in which the movable contactor is brought into contact with the fixed electrode.

Abstract: Disclosed is a circuit breaker having an automatic release linkage capable of preventing damage and deformation of elements by automatic linkage release before electro-impulsive force generated from within the circuit breaker by a large short-circuit current causes the damage and deformation of open/close linkage.

Abstract: A mold cased circuit breaker is disclosed that enables a user to easily discern an actually connected state between stationary contactors and movable contactors and forcibly separates a connection therebetween if there arises electrical fault, wherein the circuit breaker comprises: a first isolation link hinged at a lower end thereof to a shaft unit and selectively engaged at an upper end thereof with a lateral surface of a lever; a second isolation link centrally formed with an oblong hole for accommodating a guide pin protruded on a side plate and linked at one end thereof to an upper end of the first isolation link; and an isolation lever adjacently positioned at one end thereof to the other end of the second isolation link, and so positioned at the other end thereof as to selectively engage with a nail, and rotatably mounted at the side plate to rotate the nail by way of operation of the second isolation link.

Abstract: Disclosed are a valve for a gas circuit breaker, and a gas circuit breaker having the same. The gas circuit breaker comprises a cylinder constituting appearance of the gas circuit breaker, and providing a gas flow path therein, a partition plate having passing holes, and configured to partition inside of the cylinder, a sleeve concentrically disposed in the cylinder, a valve body inserted into the sleeve, and mounted below the partition plate so as to perform a reciprocation along the sleeve, an elastic means configured to upwardly apply an elastic force on a bottom surface of the valve body, and a blocking plate inserted into the sleeve, and mounted between the valve body and the partition plate so as to be moveable in upper and lower directions, wherein the valve body is provided with discharge openings, and the discharge openings are open and closed by movements of the blocking plate.

Abstract: Disclosed is a slide type movable contactor for a circuit breaker with a slidable structure by which a contact pressure with the movable contactor is increased in a conduction state so as to minimize resistance and heat generation, the assembly including a movable contactor rotatable based upon a rotational shaft, connection plates configured to allow rotation of the movable contactor and simultaneously provide a conduction path by a contact with the movable contactor, and bimetal plates installed at side surfaces of the connection plates, respectively, and bends towards the connection plates in response to a temperature increase in a conduction state to press the connection plates so as to increase a contact pressure of the connection plates onto the movable contactor.

Abstract: An inverter detects whether a fault that an over current is supplied to a load is generated when the inverter supplies AC power and operates the load, and uses a voltage between a collector and an emitter of a switching element for detecting whether an over current is supplied to the load. The inverter cuts off a switching control signal, switches DC power by a plurality of switching elements supplying AC power to the load, detects the generation of the fault by a plurality of fault detecting units using the voltage of both ends of the collector and the emitter of a plurality of switching elements, generates the switching control signal by a controlling unit that outputs the switching control signal to a switching operation unit, and detects the generation of a fault by any of the plurality of fault detecting units.

Abstract: Disclosed is a transfer device for an automatic transfer switch. With the configuration of the transfer device, the transfer device, which is installed between a plurality of air circuit breakers to allow switching of a closed state and a tripped state of the plurality of air circuit breakers, can be modularized so as to be easily assembled. A length of a transmission rod can be adjusted so as to facilitate assembly and maintenance of the transfer device and also minimize the probability of occurring an assembly error, allowing accurate closing and trip operations. The transmission rod may be provided with a buffer to reduce impact noise generated upon switching of the closing and trip operations of each air circuit breaker and enhance reliability of the device.

Abstract: Disclosed is a gas insulation circuit breaker with a structure for decreasing friction. The gas insulation circuit breaker comprises: a movable side supporting plate; a cylinder mounted so as to perform a reciprocating movement in a state that an outer surface thereof comes in contact with an inner surface of the movable side supporting plate; a contact spring for conduction disposed between the movable side supporting plate and the cylinder; and a movable arc contactor and a fixed arc contactor installed at the movable side supporting plate and the cylinder, respectively, and contacting and separated from each other by movement of the cylinder, wherein an end of the cylinder is tapered, and the outer surface of the cylinder comes in contact with the contact spring for conduction after a predetermined time lapses in a state that the cylinder has started to perform a closing operation during a circuit breaking operation.

Abstract: Provided are an RFID reader reading data from an RFID tag using a wireless connection over a specified frequency bandwidth, including a transmitting unit synthesizing sequentially and cumulatively frequency control signals generated every clock, mixing the synthesized specific frequency signal and a fixed frequency signal, and as a result outputting an RF signal.

Abstract: Disclosed is a device for preventing withdrawing and inserting of a circuit breaker. The device for preventing withdrawing and inserting of a circuit breaker include: a lead screw is coupled between a carriage and a girder assembly and rotated by an external force to allow a breaker body to be closed or released while the carriage is moved with respect to a cradle, and a braking unit preventing the lead screw for operating when the girder assembly is released from the cradle. In an unstable state in which the girder assembly is not coupled to the cradle, a withdrawal handle is prevented from being inserted into the girder assembly. Therefore, an abnormal withdrawing operation can be prevented, and thus, various safety accidents, a contact resistance and temperature rise, damage to a device due to electrical breakdown can be prevented.

Abstract: The present invention is to provide a main circuit terminal assembly for a vacuum circuit breaker, which can prevent temperature increase by increasing a surface area of a main circuit conductive unit, the main circuit terminal assembly for a vacuum circuit breaker which is electrically connected to a vacuum interrupter, including: a clamp electrically connected to a movable unit of the vacuum interrupter, and configured as a pair of conductors so as to support the movable unit by clamping; a heat sink fixed to the clamp that increase a surface area of the clamp; a flexible shunt having one end thereof electrically and mechanically connected to the clamp, and configured as a flexible conductor to allow the movable unit to move; a terminal block electrically and mechanically connected to another end of the flexible shunt, and configured as an electrical conductor; and a contactor unit electrically connected to the terminal block and having a plurality of clip-shaped contactors.

Abstract: An apparatus for processing digital input signals transferred from a plurality of circuit breakers includes: a plurality of signal input terminals configured to receive a plurality of digital input signals, which are generated from the plurality of circuit breakers and indicate an ON/OFF state of the plurality of circuit breakers, in parallel; a digital input signal parallel-to-serial converting unit configured to convert the parallel digital input signals from the plurality of signal input terminals into serial digital input signals, and output the converted serial digital input signals according to a control signal; and a controller configured to receive and process the serial digital input signals transferred from the digital input signal parallel-to-serial converting unit, and transmit the control signal to the digital input signal parallel-to-serial converting unit.