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.


Patent
Railway Technical Research Institute and Meidensha | Date: 2016-01-13

An overhead line position measuring apparatus which also enables contactless three-dimensional position measurement using an inspection car as to an overhead line other than a contact wire. The overhead line position measuring apparatus includes: first and second three-dimensional measuring devices; first and second cameras; a region of interest setting part for setting at least one region of interest based on angle data and distance data generated by each of the first and second three-dimensional measuring devices; an image processing part for performing image processing on each of first and second image data respectively generated by the first and second cameras to mask the image except for the region of interest, and accumulating the first and second image data into amemory; an overhead line extracting part for extracting an overhead line satisfying a predetermined condition from a two-dimensional image represented by each of the accumulated first and second image data; and an overhead line position calculating part for calculating a position of the overhead line in relation to the railway vehicle based on coordinates of the overhead line extracted by the overhead line extracting part.


Patent
Meidensha | Date: 2016-12-07

A periodic disturbance suppressing control apparatus is designed to estimate and correct an inverse model of a transfer characteristic of a real system successively even in case of large condition change in the real system, and to realize a stable control system. A periodic disturbance of an object to be suppressed is outputted as a sensed periodic disturbance ISdn, Isqn of a direct current component. A difference between a signal obtained by multiplication of the sensed periodic disturbance ISdn, Isqn with a multiplier using a reciprocal Qn of a transfer characteristic, and a signal obtained by adding only a detection delay to a periodic disturbance suppressing command I^(*)dn, I^(*)qn, to estimate the periodic disturbance dI^dn, dI^qn. Thee periodic disturbance suppressing command is calculated by calculating a deviation between the estimated periodic disturbance dI^dn, dI^qn. A learning control section 29 corrects the reciprocal Qn of the transfer characteristic in accordance with a quantity obtained by diving a difference of the periodic disturbance suppressing command I^(*)dn, I*qn during one sample interval by a difference of the sensed periodic disturbance during the one sample interval.


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.


Patent
Meidensha | Date: 2016-09-14

To prevent oil from adhering to a brake disc when the oil leaks from a bearing unit. A first bearing unit (b1) of a motor (110) is disposed in a state of being inserted into a bearing unit insertion part (124) of a sheave (120), and is therefore positioned on the inner peripheral side of a rope winding part (122). The rope winding part (122) of the sheave (120) has a brake disk (D) formed integrally therewith on the motor side. In order to prevent oil from reaching the brake disk (D) when oil leaks out from the first bearing unit (b1), three systems of oil guide structures (210, 220, 230) for guiding leaked oil to a position set apart from the brake disk (D) are provided.


Patent
Meidensha | Date: 2016-11-02

Due to increase of demand for safety of device, reinforcement of insulation of exposed conductive parts is required also in power conversion device. Relay unit having optical transmission unit, signal processing unit and power generating unit is provided between control circuit unit and gate drive circuit unit which form control device for an inverter. A gate signal generated in the control circuit unit is inputted into the signal processing unit of the relay unit through the optical transmission unit, and is outputted to the gate drive circuit unit from the signal processing unit through the optical transmission unit. Further, AC power is supplied to the power generating unit of the relay unit from a control device low-voltage AC power source through high-withstand voltage transformer. AC power is supplied to the gate drive circuit unit from the power generating unit of the relay unit through high-withstand voltage transformer.


Upon turn-off of IGBT, by suppressing variations in collector-emitter voltage between IGBTs connected in series, risk of breaking IGBT due to overvoltage breakdown can be reduced. In protection circuit provided for each of the plurality of IGBTs 50 connected in series, between collector and emitter of IGBT 50, avalanche elements D1 D5, resistance R4 and avalanche element D6 are sequentially connected in series. Capacitor C1 and resistance R1 are connected parallel between both ends of the avalanche element D4, and capacitor C2 and resistance R2 are connected parallel between both ends of the avalanche element D5 . Between a common connection point of the resistance R4 and the avalanche element D6 and gate of the IGBT 50, resistance R5, a parallel circuit of capacitor C3 and resistance R6, and a series component of Zener diodes ZD1 and ZD2 whose polarities are opposite to each other, are connected in series.

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