Tokyo, Japan
Tokyo, Japan

Meidensha Corporation is a Japanese, Tokyo-based company, engaged in the manufacturing and selling of generators, substation equipment, water treatment equipment, electronic equipment, and information equipment. It is listed on the Tokyo Stock Exchange and is a constituent of the Nikkei 225.The company was established by Hosui Shigemune for the manufacture of electric motors in Kyobashi, Tokyo. Wikipedia.


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Patent
Meidensha | Date: 2015-02-17

An electrode material wherein Cr-containing particles are finely miniaturized and uniformly dispersed while a Cu portion, which is highly conductive component, is also finely miniaturized and uniformly dispersed. The electrode material is prepared, for example, by: a mixing step (S1) for mixing a Cr powder and a heat resistant element powder; a provisional sintering step (S2) for provisionally sintering the mixed powder to obtain a solid solution of Cr and the heat resistant element; a pulverizing step (S3) for pulverizing the solid solution of Cr and the heat resistant element to obtain a solid solution powder of Cr and the heat resistant element; a molding step (S4) for molding the solid solution powder; a main sintering step (S5) for performing main sintering of the obtained molded body to obtain a sintered body (skeleton) of Cr and the heat resistant element; and a Cu infiltration step (S6) for infiltrating the sintered body of Cr and the heat resistant element with Cu. A method for producing an electrode material, involving: (i) a step of preparing a powder of a solid solution of Cr and a heat resistant material selected from the group consisting of Mo, W, Ta, Nb, V and Zr, wherein either a peak corresponding to Cr element or a peak corresponding to the heat resistant element, which are observed by X ray diffraction measurement made on the powder of the solid solution, disappears; (ii) a step of molding the powder of the solid solution to obtain a molded body and then sintering the molded body to produce a sintered body; and (iii) a Cu infiltration step of infiltrating the sintered body with Cu.


Patent
Meidensha | Date: 2015-02-17

A method for producing an electrode material, provided to involve: (i) a provisional sintering step of sintering a mixed powder containing a powder of a heat resistant element and a powder of Cr to obtain a solid solution where the heat resistant element and Cr are dissolved; (ii) a pulverizing step of pulverizing the solid solution to obtain a powder; (iii) a main sintering step of sintering a molded body obtained by molding the powder of the solid solution, to produce a sintered body; and (iv) a Cu infiltration step of infiltrating the sintered body with Cu.


A elevator car movement control apparatus is provided to move an elevator car in a light load direction judged without using a load or torque sensor at the time of power outage. A control section of an inverter 80 supplying a voltage to an elevator drive motor 50 includes a speed control system arranged to determine a torque command value from a deviation between a speed command and a sensed speed and to control the speed of motor 50 in accordance with the torque command value, including a zero speed region, controls the speed control system in a zero speed control in an open state of a brake at the time of operation by an emergency power source due to outage of an input power source, calculates a torque command value in the speed control system at that time, to detect the light load direction of the motor decided by the weight balance between a counterweight 53 and the car 54 among the rotational directions sensed by an encoder 56, and controls the car 54 to move in the light load direction with a speed command value corresponding to the detected light load direction.


A resonant load power conversion apparatus is provided to lower a switching frequency of each switching device and to reduce the number of main circuit conductors. The conversion apparatus includes a single-phase inverter having a dc input side (Vdc) connected with a dc voltage source and an output side (Vout) connected with a resonant load and outputting a rectangular wave voltage with a resonance frequency. Upper and lower arms on the input side and output side of the single-phase inverter are connected, respective, with switch group circuits 100U, 100V, 100V and 100V each of which includes N series combinations (N is an integer equal to or greater than 2) of two switching devices, connected in parallel with each other by main circuit conductors. The switching devices of the switch group circuits are controlled in a time division switching control mode with a control section.


Patent
Meidensha | Date: 2017-05-03

The tap positions of a first and a second tap switching transformers are respectively set as a large output position and as a small output position until all of the pantographs of an electric vehicle pass through an inlet-side air section. After all of the pantographs pass through the inlet-side air section before a front-side pantograph of the electric vehicle reaches the outlet-side air section, the second tap switching transformer tap position is gradually switched in an output increasing direction while the first tap switching transformer tap position is switched in an output decreasing direction, and the tap positions of the first and the second tap switching transformers are respectively set as the small output position and as the large output position. Thus, in the central section of power supply equipment for an AC electric vehicle, power supply phase-switching is performed without a momentary power failure.


The invention relates to a monitoring device for a surge arrester comprising a means 6 for detecting a total leakage current that is flowing between the surge arrester 3 and earth, a field sensor 9 for detecting an electrical field in the vicinity of the surge arrester 3 and a communication unit 13 for the contact less transmission of data to an external device 2, the communication unit 13 being a near-field communication unit for the contact less exchange of data by means of near-field communication (NFC).


The invention relates to a method for producing a surge arrester, comprising the steps of:


When it is not possible for a power generation device to operate coupled to an electric power system, an autonomous operation of connection and disconnection of a load of the power generation device is performed along an efficiency-characteristics curve within a speed range from a rated speed to a maximum speed in the efficiency-characteristics curve of an energy source. During the autonomous operation, an aperture command is outputted to an inlet valve of a water turbine and a first converter is operated in a converter mode when an operation preparation command is outputted by a control unit, a second converter is operated in an inverter mode when a voltage is established by of a DC linkage unit, and the load is connected when the operation preparation is completed.


Patent
Meidensha | Date: 2016-06-08

A multilevel power conversion device comprises: N DC power supplies (DCC1 to DCCN) (N 1) connected in series and common to each phase; first flying capacitors (FC1, FC3, ..., FC2N-1) having one end connected to the negative electrode end of each of the DC power supplies (DCC1 to DCCN) and common to each phase; a second flying capacitors (FC2, FC4, ..., FC2N) having one end connected to the positive electrode end of each of the DC power supplies (DCC1 to DCCN) and common to each phase; and a phase module using, as input terminals, the positive and negative electrode ends of the first flying capacitors (FC1, FC3, ..., FC2N-1) and the positive and negative electrode ends of the second flying capacitors (FC2, FC4, ..., FC2N). In the phase module, a capacitor (FC1u) is connected in parallel with the two switching elements (Su7, Su8) of an output stage. This reduces the number of elements used in a multiphase multilevel power conversion device, thereby reducing the cost of the device and reducing the size of the device.


Patent
Meidensha | Date: 2016-11-02

Consumption of regenerated power by a regeneration inverter for electric railroads must rely on lighting and power supplies in yards, and can only consume a fraction of the regenerated power generated by a train. Switching switches switching a connection between electric car lines and a storage medium of a power storage device are connected respectively to the positive and negative electrodes on the direct current side of the regeneration inverter. The switching switch connected to the regeneration inverter positive electrode side performs control so as to switch to the electric car line side when charging the storage medium and to the storage medium side when discharging. The switching switch connected to the regeneration inverter negative electrode side is configured so as to switch to the storage medium charging side terminal through the regeneration inverter when charging, and to the negative electrode side of the electric car lines when discharging.

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