Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Mitsuru Tsukima

Toshie Takeuchi

Kenichi Koyama

Hiroyuki Akita

Kazuki Takahashi

Hiroyuki Sasao

Yukimori Kishida

Takafumi Nakagawa

Toyomi Ooshige

Hidetoshi Kitanaka

Shinji Yamagata

Taehyun Kim

Takao Mitsuhashi

Masahiro Fushimi

Makoto Kanemaru

Nobumoto Tohya

Tomoko Takasuka

Mitsugi Mori

Toru Kimura

Yasushi Takeuchi

Tetsuya Matsuda

Toshiyuki Yoshizawa

Koichiro Kamei

Hitoshi Sadakuni

Toshihiro Matsunaga

Katsuhiko Horinouchi

Naohito Kaneda

Hideo Okayama

Mitsugu Takahashi

Shinichi Furutani

Yoshiharu Kobayashi

Kazunori Fukuya

Shiro Murata

Tomoko Tanabe

Akihiko Maruyama

Hitoshi Gotou

Toshihiko Miyauchi

Noriaki Moriyama

Takuya Ohkubo

In a DC feed system configured by a plurality of DC electrical circuits being combined, when an arc fault occurs, it is difficult to identify a DC electrical circuit in which an arc has occurred. For this reason, a DC electrical circuit protection apparatus includes: a plurality of DC electrical circuits, each of which has a current sensor provided in at least one of a positive or a negative electrical path and has arc noise absorbing mechanism on the upstream side of the current sensor; and an arc detection device which compares respective arc noise signal strengths of the DC electrical circuits from current signals detected by the current sensors of the DC electrical circuits, and based on the signal strengths, identifies a circuit in which an arc has occurred, wherein a DC electrical circuit in which an arc has occurred is identified.

DC electrical circuit protection apparatus and ARC detection method

The power transmission mechanism abnormality diagnostic device includes a monitoring diagnosis unit for performing determination as to abnormality of a power transmission mechanism, and a current detector connected to a power supply of an electric motor, wherein the monitoring diagnosis unit includes an analysis unit for analyzing current transmitted from the current detector and an abnormality determination unit for performing determination as to abnormality of the power transmission mechanism on the basis of a result of analysis by the analysis unit.

Abnormality diagnostic device for power transmission mechanism and abnormality diagnostic method for power transmission mechanism

In an electromagnetically moving device, a magnetic-flux variation measuring unitis placed at a position which is outside a closed magnetic path established when a movable coreand a stationary coreare being attached to each other due to permanent magnets, and at which a leakage magnetic-flux variation due to movement of the movable corecan be measured, so that a behavior of a movable part in a switch, etc. is estimated such that an inflection point time is calculated from the measurement of time-series data of the magnetic-flux variation.

Electromagnetically moving device

An electromagnetically operated device includes: a moving member of the electromagnetically operated device; a drive coil that is energized to generate magnetic flux for driving the moving member; a permanent magnet provided between a stationary member and the moving member for holding the moving member; and a holding force adjusting member for adjusting the holding force applied to the moving member by the permanent magnet, wherein the holding force adjusting member is placed at a position that will not be included in the main magnetic path of the magnetic flux caused by the drive coil so as to be removable.

Electromagnetically operated device and switching device including the same

An AC motor drive control device including: an inverter, having a plurality of switching elements subjected to on-off control, for converting a DC voltage to an AC voltage with a desired frequency to drive an AC motor; a motor opening contactor connected between the inverter and the AC motor; a switching operation beforehand detection unit for detecting a switching operation of the motor opening contactor prior to the contact or detach of main contacts and outputting a switching operation beforehand detection signal; and a control unit having an inverter control unit for performing the on-off control for the plurality of switching elements and switching control for the motor opening contactor, and controlling the inverter based on the switching operation beforehand detection signal.

AC motor drive control device

An object is to provide a driving controller for an AC motor that can prevent generation of an excessive voltage between lines of a motor and between contacts of a motor cut-off contactor and a continuous arc between contacts of the motor cut-off contactor, regardless of the type of a fault occurred, even when a phase in which a current zero point is not generated and a phase in which a current zero point is generated coexist in a fault current that flows between an inverter and the motor. A control unit is configured to open a motor cut-off contactor not at a time when a state of a detected current is determined to be abnormal but at a time when the state of the current is determined to be normal, even when a basic contactor-close command MKC0 becomes off (L level).

Driving controller for AC motor

An object is to provide gas insulated switchgear that is able to inhibit heat generation of a pressure container. Electrically-conductive members that are non-magnetic and have higher electric conductivity than that of the material of which the pressure container is made, are provided on the inside and on the outside of the pressure container, while being positioned along a main bus and being attached via a flange of the pressure container. Thus, eddy current that occurs when an electric current flows through the main bus are caused to flow through the electrically-conductive members having higher electric conductivity than that of the pressure container. Also, a current return path for the eddy current is formed by a flow path including the electrically-conductive members. Consequently, it is possible to reduce the eddy current flowing on the pressure container and to inhibit an increase in the temperature of the pressure container.

Gas insulated switchgear

In an electromagnetic switch for an auxiliary-rotation starter according to the present invention, the magnetic bypass core is disposed at a place that is an air gap portion, in a magnetic circuit, through which the plunger moves due to magnetic attractive force produced by energizing the attraction coil and the holding coil and that is between the outer circumference of the plunger and the inner circumference of the bobbin, in such a way that one end thereof makes contact with one end of the case and the other end thereof faces the end of the core by the intermediary of an air gap.

Electromagnetic switch for auxiliary-rotation starter

A three-stable oscillating electromagnetic actuator includes a cylindrical stator from which a plurality of first magnetic poles project toward a center direction, a mover that extends in a circumferential direction inside the stator and is reciprocatingly and rotatably supported along the circumference, and a plurality of coils that are wound around the first magnetic poles and bias the mover to cause it to stop in three positions, which are a first stable position that is on one end side of a rotation range of the mover, a second stable position that is on the other end side, and a neutral position that is an intermediate position. The three-stable oscillating electromagnetic actuator further includes a second magnetic pole made of a magnetic material that abuts against a rotation-direction end of the mover to stop the mover in the first stable position and the second stable position.

Three-stable oscillating electromagnetic actuator

A state grasp device that needs no optical adjustment, and can be downsized. An exciting current waveform of an opening electromagnetic coil of an electromagnetic operating set functioning to drive a moving contact of a switching device includes an inflection point appearing subsequently to a maximum value, the inflection point taking place at the time of the contact being parted. Accordingly, a wear amount of contact from the change over time can be obtained. A position of the inflection point is obtained, for example, by focusing the rate of change in current; and a wear amount of a switching contact is obtained from the change over time of a time when the inflection point takes place. With the device, the use of a mechanical detection device, such as an optical detector, can be eliminated.

State grasp device, and switching control device of power switching apparatus employing the state grasp device

A magnetic actuator includes a first yoke, an armature which is provided inside the first yoke and made movable in reciprocating motion along a first direction inside the first yoke, first and second coils fitted inside the first yoke, a pair of second yokes affixed to the first yoke along a second direction, and permanent magnets affixed to the second yokes in a manner that the permanent magnets are positioned face to face with the armature. In the magnetic actuator thus constructed, fluxes generated by the first and second coils pass through first magnetic circuits whereas fluxes generated by the permanent magnets pass through second magnetic circuits differing from the first magnetic circuits.

Magnetic actuator

In an actuator, coils are kept from being displaced along a y-axis direction as projections of coil bobbins are sandwiched between first and second iron cores along the y-axis direction. Also, the coils are kept from being displaced excessively along x- and z-axis directions due to shocks, for instance, because they are fitted in groovelike channels fitted in the first and second iron cores. Since two bearings are sandwiched and fixed between third and fourth iron cores along the x-axis direction, the bearings can be easily set on a common axis with high accuracy. It is therefore possible to prevent displacement of the coils during operation of the actuator. Slidable support plates ensure smooth movements of an armature and thereby provide improved reliability, even when the distance between the support plates and the first to fourth iron cores is reduced.

Actuator, method of manufacturing the actuator and circuit breaker provided with the actuator

In an operation circuit of an electromagnetic switching device, when electric energy is discharged by discharge switches connected in series, respectively, to opening coils and closing coils, an induction current flowing in a direction opposite to a current of the coil of the excitation side is generated. The current flows through the coil on the non-excitation side due to magnetic coupling, and a magnetic flux necessary for driving is cancelled, thereby inhibiting generation of a driving force. The operation circuit includes first and second opening and closing coils, so that a moving element may be driven between those coils. This circuit includes a circuit for suppressing an over-voltage at the moment of interrupting an excitation current of a first coil and for interrupting an induction current generated through the first coil at the time of exciting the second coil.

Operation circuit and power switching device employing the operation circuit

A switching apparatus for multiphase electric power includes switching units corresponding to different phases. Each switching unit includes an operating mechanism having a movable coil disposed between two fixed coils, and a switch portion having a movable contact operatively connected to the movable coil. A separate power supply may be provided for each switching unit to permit individual control of the different phases.

Switching apparatus

A switching device includes a pair of fixed coils and a pair of movable coils, with one pair being disposed between the other pair. Two of the coils may be connected back to back on opposite sides of a support plate to increase the stiffness of the coils and reduce damage due to impact between the fixed and movable coils. The coils include two sets of coils, each set including one of the fixed coils and one of the movable coils. The coil sets can be driven simultaneously or at different times to effect contact opening and closing.

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Tokyo, Japan

Mitsuru Tsukima