Abstract: An air circuit breaker is provided wherein a rotational force is accurately discontinued at a movement completion time of assuming a connected position, a test position or a disconnected position by a breaker body in the process of withdrawing in and withdrawing out the breaker body from a cradle whereas a driving connection is performed if necessary, the breaker including a coupling device capable of being moved to a position where a withdraw-in and withdraw-out driving force generated by a manipulating handle is transmitted to a withdraw in and withdraw out apparatus and to a position where the withdraw-in and withdraw-out driving force is stopped of transmission.

Abstract: A resistive superconducting fault current limiter comprises: a superconducting limiter element which is in a superconductive state in the event of a normal current occurrence, and which is in a normal conductive state having a predetermined resistance when a fault current larger than a predetermined threshold current value flows; a superconducting serial coil serially connected to the superconducting limiter element so as to face each other so that a current loss can be minimized accordingly as currents flow in opposite directions thus to cancel magnetic fields, and having a threshold current value greater than the threshold current value of the superconducting limiter element by a predetermined ratio; and a normal conductor parallel coil connected to the superconducting limiter element in parallel and having a predetermined resistance smaller than the resistance of the superconducting limiter element when a fault current occurs, for preventing the superconducting limiter element from being overheated by divi

Abstract: An electric power circuit protecting apparatus using a superconductor in an electric power system needing re-closing within a predetermined time from fault current blocking, comprising a main circuit breaker; a first superconductor element connected in series to the main circuit breaker; a first auxiliary switch to switch a circuit between the first superconductor element and the main circuit breaker; a second superconductor element connected in parallel to the first superconductor element and the first auxiliary switch; a second auxiliary switch to switch a circuit between the second superconductor element and the main circuit breaker; a first monitoring unit for detecting a voltage across the first superconductor element and for supplying a first switching control signal to the first auxiliary switch to be switched to the circuit open position, and a second switching control signal to the second auxiliary switch to be switched to the circuit close position; and a second monitoring unit for detecting a volta

Abstract: Disclosed are a multi-pole circuit breaker and an apparatus for preventing deformation of a driving shaft thereof. The multi-pole circuit breaker includes: a plurality of single pole breaking units having a pair of fixed contactors, a movable contactor, and shafts; a switching mechanism disposed on a certain one of the plurality of single pole breaking units; a pair of driving shafts connected to each shaft; and a driving shaft deformation prevention unit disposed between the single pole breaking unit, spaced relatively far from the switching unit among the plurality of single pole breaking units, and the adjacent single pole breaking unit.

Abstract: Disclosed is a multi-pole circuit breaker. The multi-pole circuit breaker includes: a substrate disposed between the single pole breaking unit, spaced relatively far from the switching mechanism as compared to the other single pole breaking units among the plurality of single breaking units, and the adjacent single pole breaking unit; a link mechanism rotatably supported on the substrate; and springs having one ends supported by the substrate and the other ends supported by the link mechanism.

Abstract: Disclosed is a half-wave expulsion type superconducting fault-current limiter having an integral high speed switch module. The fault-current limiter has minimum superconducting elements and a circuit of which is formed in a hybrid type with an integral high speed switch module. The fault-current limiter supplies an electric power supplied from a power feeder to a system without loss thereof according to unique characteristics of the superconducting element when a normal current flows, and restricts an over current through a high speed switching contact point integrally inter-working with a driving coil and an arc changeover switch past a half period in a case that the over-current is generated by accidents such that electric power appliances, including circuit breakers in an electric power system, can be normally operated.

Abstract: Disclosed is a discharging control apparatus of a switching device for an inverter capable of reducing a spike voltage when the switching device is turned off and reducing a turn-off time of the switching device, the apparatus comprising, a fast discharge circuit section configured to provide a discharging path through which a gate voltage of the switching device is fast discharged at a first discharging speed, an idle discharge circuit section configured to provide a discharging path through which the gate voltage of the switching device is idly discharged at a second discharging speed slower than the first discharging speed, and a spike voltage reduction controller configured to control such that the gate voltage is discharged simultaneously via the fast discharge circuit section and the idle discharge circuit section, when the switching device is turned off in the state that a normal current flows in the switching device, so as to reduce a spike voltage and simultaneously fast turn the switching device off

Abstract: An actuator using a permanent magnet comprises: a first core and a second core facing each other with a certain gap and having a space therein; a hollow bobbin coil fixedly installed at one side of the space for generating a magnetic force at the time of a current supply; a stator fixedly installed at another side of the space with a certain gap from the bobbin coil; a mover linearly moving in the space by a magnetic force generated by the bobbin coil, and having a rod portion exposed to outside of the first core and the second core; and a permanent magnet fixedly installed at an inner surface of the space for fixing the mover. In the actuator, one bobbin coil is provided thus to lower a production cost, and a driving function is enhanced. Accordingly, the actuator can be widely applied to a vacuum circuit breaker or a high speed transfer switch requiring a fast driving.

Abstract: Disclosed is provided a hybrid-type superconducting fault current limiter for rapidly limiting a fault current, the fault current limiter having a first circuit and a second circuit which are connected in parallel with each other, wherein the first circuit includes a superconductor and a circuit breaker which are connected in series with each other, and wherein the second circuit includes a driver having a driving coil and an electromagnetic repeller, a short contact connected in parallel with the driver, and a current limiting unit connected in series with a third circuit including the driver and the short contact. The hybrid-type superconducting fault current limiter comprises a power semiconductor element switch connected in series with the first circuit, the power semiconductor element switch normally maintaining an ON state and being activated and changed into an OFF state by a fault sensing signal generated according to an inflow of the fault current.

Abstract: In a terminal of a standard, plug-in or box type molded case circuit breaker, a terminal module assembly for a molded case circuit breaker capable of being removable by easily selecting the terminal type, and a molded case circuit breaker having the terminal module assembly, the terminal module assembly comprising a plurality of terminals provided to selectively have a standard, plug-in or box type and electrically connected to fixed contactors, a plurality of terminal bases provided as many as the number of the terminals and selectively having the standard, plug-in or box type, thus to fixedly support each of the terminals, wherein each terminal is assembled to each terminal base to obtain a terminal module intermediate assembly, and a common supporting base for supporting all of the plurality of intermediate assemblies regardless of the terminal type or terminal base type, wherein the terminal module assemblies having the construction can be attached/detached to/from the molded case circuit breaker.

Abstract: A thermal overload trip apparatus capable of minimizing inferiority caused by a variation when manufacturing an adjusting means and simply adjusting sensitivity by duplicating the means for adjusting a sensitivity of a trip operation current, comprising, a trip mechanism driven to a trip position by a driving force from a shifter mechanism on occurrence of an overload on a circuit; a release lever mechanism for driving the trip mechanism to the trip position by pressing it when there is the driving force from the shifter mechanism or for releasing the trip mechanism when there is no driving force, on occurrence of the overload on the circuit; an adjusting lever for operating the release lever mechanism to be horizontally moved by rotation; an adjusting knob having an upper surface having a setting groove and a lower portion having a cam portion; and a means independently adjusting the sensitivity of the trip operation current regardless of manipulating of the adjusting knob.

Abstract: A method for adjusting a trip sensitivity in a thermal overload protection apparatus so as to effectively set and adjust a trip operation current, comprising: setting an adjusting reference point; measuring a normal position of bimetals; measuring a moving distance at a time of trip operation of a trip latch mechanism; deciding an assembling position of a shifter mechanism based on the measured moving distance at the time of trip operation of the trip latch mechanism, information on a trip distance between a pre-determined shifter mechanism and the trip latch mechanism and information on a size of the shifter mechanism; conducting a predetermined over current to the thermal overload protection apparatus; measuring a conducting time of the overcurrent until a trip occurrence; calculating a difference between the conducting time measured in the measuring step and a predetermined trip time by converting a rotation angle; and marking a graduation of a set trip operation current by the rotation angle calculated in

Abstract: A molded case circuit breaker having a contact on mechanism which can perform a trip operation and automatically rotates the handle to the on position or a position toward the on position if the handle is manipulated to move to the off (or reset) position in a state that the contacts are melt-adhered to each other, the contact on mechanism, including: a contact on plate which is vertically movable by being guided according to the operation of the switching mechanism, a trip bar that drives the restricting unit to a releasing position, a lever connected to the handle and that provides a pivot point of the handle, a lever pin fixed to the lever, for driving the restricting unit to the releasing position by pressing the trip bar, and thereby operating the switching mechanism to the trip position, and a trip spring providing an elastic driving force for enabling the switching mechanism to operate to the trip position when the restricting unit is moved to the releasing position.

Abstract: The present invention previously sets a threshold voltage, compares the set threshold voltage with a reference voltage, and judges whether a minimal pulse width of a PWM signal is obtained. When a pulse width of one PWM signal is equal to or greater than the minimal pulse width, but each pulse width of two PWM signals is less than the minimal pulse width, a sine wave voltage corresponding to one of the two PWM signals less than the minimal pulse width is varied to a threshold voltage to detect two phase currents, and a remaining one phase current is calculated based on the two detected phase currents. After the phase current was detected by varying the threshold voltage, a level difference between an original sine wave voltage and the threshold voltage is set as a compensation voltage, and the sine wave voltage is compensated by the compensation voltage.

Abstract: A movable contactor for an air circuit breaker with a contact spring protecting mechanism is provided, the movable contactor comprising a shielding plate configured to shield exposed surfaces of the contact springs for protection so as to prevent a deterioration or performance degradation in the contact springs due to arcs.

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: A time delay output apparatus for a circuit breaker includes a switch disposed at one side of a main shaft rotatable in directions to open/close a fixed contactor and a movable contactor, and a delay member disposed between the main shaft and the switch so as to operate the switch with a preset time delay, thereby simplifying the construction and reducing the size as well as enhancing operational reliability by stably obtaining a time delay.

Abstract: Disclosed is a draw in-out apparatus that is suitable for an air circuit breaker having large capacity and size, the apparatus comprising: a movable plate meshed with the thread portion of a spindle so as to be movable back and forth; rack gear installed on the movable plate so as to be movable back and forth along with the movable plate moving back and forth; pinion gear installed to be meshed with the rack gear and rotatable according to the rack gear moving back and forth; a cam rotatable by a rotational driving force transferred from the pinion gear by being provided with a teeth portion meshed with the pinion gear and having a radius larger than those of the pinion gear so as to amplify a torque transferred from the pinion gear and provided with a cam slot portion for enduring a load of the main body and a reaction force generated when the main body and the cradle are electrically connected to each other while the main body is moved to a connected position; a pivot disposed on the cradle at a position ad

Abstract: Disclosed is a control terminal automatic connection apparatus for an air circuit breaker and an air circuit breaker having the same, the apparatus comprising: a cam, a lever having one end portion that can be connected to the cam or separated from the cam and rotatable by the rotation driving force transferred from the cam when connected to the cam, a rod connected to the lever and thus movable in a vertical direction according to the rotation of the lever, a fixed control terminal module fixedly installed at the main body, and a movable control terminal module installed at the cradle and movable to a position for being connected to the fixed control terminal module of the main body and a position for being disconnected therefrom.

Abstract: An air circuit breaker having a mechanical trip indicating mechanism, in an air circuit breaker including a switching mechanism, an actuator having an output link for providing a mechanical driving force, a first link unit connected between the output link of the actuator and the switching mechanism for applying the mechanical driving force from the output link to the switching mechanism to perform a trip operation, a front surface plate provided with a manipulating unit accessible by a user, the air circuit breaker comprising: a first rotation lever connected to the first link unit, a second link unit limitedly moved by the first rotation lever, a bias spring for applying an elastic biasing force to the second link unit to be moved in one direction, a second rotation lever installed to be rotatable with coming in contact with one end portion of the second link unit, and a mechanical trip indicating mechanism supported by the front surface plate and having an indicating portion exposed to the front surface pl