Abstract: A coil-driving apparatus of an electro magnetic contactor is disclosed, which replaces the main units in an analog scheme with those in a digital scheme using a PWM controller of low power consumption to reduce the number of the analog components, minimize power consumption, and controls a constant voltage that flows on the coil by receiving the feedback current flowing on the coil, whereby error and defect generation rates are reduced, and deterioration and burning of components are prevented.

Abstract: Disclosed is a plug interlock device for a vacuum circuit breaker. Only after a plug is completely mounted to a connector, an insertion or withdrawal operation by a vacuum circuit breaker is performed. Accordingly, while a breaker body is moved to a ‘RUN’ position from a ‘TEST’ position, or when an operation is performed at a ‘RUN’ position, the plug may be prevented from being separated from the connector. This may prevent an accident.

Abstract: Disclosed is an RFID-based reader configured to allow a UHF band RFID reader unit to recognize an RFID tag in a short distance, and to minimize an erroneous recognition, the reader including a gate frame discretely installed at both sides of an entrance and exit, a parabolic surface type reflective plate perpendicularly installed inside of the gate frame, an array antenna arranged on the reflective plate for receiving a tag information transmitted from an RFID tag, and an RFID reader unit for controlling an operation of the array antenna and converting the tag information received from the array antenna to a tag data.

Abstract: An apparatus for controlling operation of inverter system configured to drive a motor by using an inverter, and to normally operate the motor in a resonance-generated frequency band if the resonance occurs, and a method thereof are disclosed, wherein the method includes detecting a current outputted by an inverter system to a motor, if an operation frequency of the motor is in a resonance frequency band, converting the detected current to a d axis current and a q axis current, calculating a difference between the converted d axis current and pre-sampled d axis current (magnetic flux portion), multiplying the calculated difference by a preset comparative control gain to calculate a comparative control voltage, and adding the calculated comparative control voltage to a torque portion voltage responsive to an operation frequency of the motor to generate a driving voltage of the motor.

Abstract: Disclosed is a vacuum circuit breaker. A rotation link provided between a rotation shaft which transfers a rotation force of a driving force, and a moveable link which performs a linear motion by a rotation force of the rotation shaft is configured to receive a tensile force to be pulled to a direction of the rotation shaft when a driving unit performs a closing operation. This may prevent the moveable link from being buckled during a closing operation, and thus prevent lowering of the reliability due to deformation of sliding levers.

Abstract: Provided herein is a power transmission mechanism of a four poles circuit breaker in which the contact points of a neutral pole thereof are brought into contact earlier at the time of closing and separated later at the time of opening than those of the other poles thereof, and according to the present invention, there is disclosed a power transmission mechanism of a four poles circuit breaker comprising: a switching shaft configured to provide a driving force for switching to the movable contactors of the poles; an arm provided to correspond to the four poles to transfer the rotational torque of the switching shaft; and a link configured to transfer the rotational torque of the arm to the movable contactor as a switching force, and provided to correspond to the four poles, wherein the sum of the length of the arm and the link in a neutral pole is longer than the sum of the length of the arm and the link in the poles excluding the neutral pole.

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 herein is an abnormal current detection circuit for circuit breaker, comprising a full-wave amplifier, a positive wave-period comparator for comparing a positive wave-period amplification voltage signal with a positive wave-period reference voltage signal to output a pulse signal, a negative wave-period comparator for comparing a negative wave-period amplification voltage signal with a negative wave-period reference voltage signal to output a pulse signal, a combining circuit for combining pulse signals outputted from the positive wave-period comparator and the negative wave-period comparator to output a full-wave combining signal, a reference voltage generator for generating a reference voltage signal, and a comparative driving circuit section for comparing the combining signal with the reference voltage signal to output a signal for controlling a circuit breaker to be driven to a circuit breaking position when the combining signal is greater or equal to the reference voltage signal.

Abstract: An electromagnetic contactor is provided an electromagnetic contactor including an upper frame having a fixed contact point and a guide rail; a cross bar comprising a sliding portion engaged with the guide rail, a movable contact point contacting and separating with respect to the fixed contact point while sliding along the guide rail, and a movable core; and a lower frame comprising a fixed core disposed adjacent to the movable core, an excitation coil magnetizing the fixed core by an electromotive force, and a return spring exerting an elastic force to the cross bar, wherein the sliding portion is configured separately from the cross bar, and a material forming the sliding portion has a friction coefficient against the guide rail less than that of the cross bar.

Abstract: Disclosed is a switching mechanism for a mold cased circuit breaker, capable of indicating a contacts status by a position of a handle.

Abstract: The present disclosure relates to a mobile rack for a library and an RFID (Radio Frequency Identification) system for a library including the same, wherein the mobile rack includes a plurality of racks configured to keep books each attached with an RFID tag and mounted with an RFID reader for recognizing tag information stored in the RFID tag, a moving unit configured to move at least one of the plurality of racks, a server configured to manage the books that are inputted, outputted and stacked, and a controller configured to control the moving means in response to a user command through the server or the tag information and to adjust a discrete distance between racks.

Abstract: An vector modulator using a time delay and a phase shifter is disclosed, the vector modulator including a time delay (110) varying a phase of an input signal by time-delaying the input signal; a first coupler (120) converting the signal outputted in changed phase through the time delay to an I channel signal and a Q channel signal each having a 90° phase difference and outputting the I/Q channel signals; a first phase shifter (130) varying the phase of the I channel signal outputted from the first coupler within a predetermined phase range and outputting the phase-variable I channel signal; a second phase shifter (140) varying the Q channel signal outputted from the first coupler within a predetermined phase range and outputting the phase-variable Q channel signal; and a second coupler (150) coupling phase-variable I/Q channel signals and outputting the coupled signals.

Abstract: A maximum power point tracking method is provided. The method includes temporarily determining a next voltage command using voltage and power measured at current and previous time points. When an increase or decrease in voltage command is continued predetermined times or more, it is decided that the next voltage command temporarily determined to be increased is decreased or that the next voltage command temporarily determined to be decreased is increased. The output voltage of a solar cell is regulated based on the decided next voltage command.

Abstract: The invention provides a micro strip antenna used for both a near-field region and a remote-field region. A micro strip antenna comprises: a first dielectric substrate; a main patch, having a triangle shape under the first dielectric substrate, configured to feed a radiation current; a second dielectric substrate over the first dielectric substrate; and a sub patch, formed under the second dielectric substrate, configured to desert a current from the main patch to provide a vertical magnetic field.

Abstract: The present disclosure relates to an RFID (Radio frequency identification) system using circular polarized antennas, wherein a reader emits electromagnetic wave through reader antennas to recognize a tag and to read out customer information if a customer proximity is detected, where the reader antennas are installed at a kiosk body and at a rear proximity position of a floor surface on which a customer using the kiosk stands, and the reader antennas installed at the rear proximity position of the floor surface emits circular polarizing wave toward the kiosk, whereby the tag can be accurately recognized regardless of position of the tag of the customer.

Abstract: Provided herein is an interlock apparatus for preventing the drawing-in or drawing-out of a vacuum circuit breaker main body in interlock with the ground operation of a ground switch in a vacuum circuit breaker, and the ground switch interlock apparatus of the vacuum circuit breaker comprising: a drive spindle; a movable plate movable to a manipulation handle connection allowance position or a manipulation handle connection prohibition position; a first interlock plate that moves the movable plate to the manipulation handle connection allowance position or the manipulation handle connection prohibition position; and a second interlock plate to be moved to a position for locking the first interlock plate at the manipulation handle connection prohibition position when the ground switch is at a ground position and a position for releasing from the restraint of the first interlock plate when the ground switch is not at the ground position.

Abstract: Disclosed is a keylock device for a circuit breaker. The keylock device for a circuit breaker comprises a closing lever configured to generate a closing operation of a mechanism, a trip lever configured to generate a trip operation of the mechanism, and a locking unit configured to allow a locked state of the locking unit to be maintained when the mechanism is in an ‘ON’ state, but to allow the locked state of the locking unit to be converted into a released state when the mechanism is in an ‘OFF’ state. Under these configurations, it is impossible to convert the current state of the keylock device into a locked state unless the mechanism of the circuit breaker is converted into an ‘OFF’ state. This may prevent the occurrence of an accidence due to the operator's unintentional ‘OFF’ state of the mechanism.

Abstract: A circuit breaker comprises a latching plate rotatably coupled to a moveable plate, and tensile type latching springs, each latching spring having two ends fixed to the latching plate and the moveable plate, respectively. Time taken for a moveable contact to be lifted up from a contact time point between the moveable contact and a fixed contact may be shortened, and thus a time duration for which an accident current flows may be reduced. Accordingly, the amount of energy applied to the circuit breaker may be reduced, and a breaking function of the circuit breaker may be enhanced. Furthermore, since a contact pressure between the moveable contact and the fixed contact has a constant change, a reliability on a conductive state of the moveable contact and the fixed contact may be enhanced.

Abstract: A circuit breaker having a stopping groove engaged with part of the main shaft and a rebound preventer rotatably installed in the circuit breaker. The stopping groove includes first and second contact surfaces contactable with the part of the main shaft upon the rotation of the main shaft. Further, an extending line of a force applied from the part of the main shaft to the second contact surface passes through the center of the rotation of the rebound preventer upon a reverse rotation of the main shaft.