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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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:


A plurality of carrier patterns, which are a carrier pattern A and a carrier pattern B, are formed by dividing triangular wave carrier signals every 1/2 cycle at a timing when the triangular wave carrier signals cross each other. A carrier pattern by which a neutral point potential is balanced is selected from the carrier pattern A and the carrier pattern B on the basis of an upper arm DC voltage detection value Ea, a lower arm DC voltage detection value Eb and an output current detection value Iout. By performing a PWM operation that compares the selected carrier pattern with an output voltage command Vref, an ON/OFF signal for the each switch is generated. With these operations, in a single-phase NPC inverter, a neutral point potential of a DC voltage is controlled without changing a switching timing.


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: 2015-06-17

Considering a case that a device requiring electric power is arranged in a room where an actuator such as an automatic driving device is disposed, a power cable, a control signal cable, and an electric power cable for the actuator are arranged in parallel and extended in one direction, and thereby a flat part is formed. In a cable side connector provided at both ends of the flat part, a connection terminal of the control signal cable is held at a position where a connection terminal of the electric power cable is put between the connection terminal and a connection terminal of the power cable.


What is disclosed is an electrode material including a sintered body containing a heat resistant element and Cr and being infiltrated with a highly conductive material. A powder mixture of a heat resistant element powder and a Cr powder is subjected to a provisional sintering in advance, thereby causing solid phase diffusion of the heat resistant element and Cr. After a Mo-Cr solid solution obtained by the provisional sintering is pulverized, the pulverized Mo-Cr solid solution powder is molded and sintered. A sintered body obtained by sintering is subjected to a HIP treatment. The highly conductive metal is disposed on the sintered body after the HIP treatment, and infiltrated into the sintered body by heating at a predetermined temperature. By conducting the HIP treatment, the withstand voltage capability and current-interrupting capability of the electrode material are improved.


Patent
Meidensha | Date: 2017-08-02

A line measurement device that has three line-sensor cameras (1, 2, 3) for imaging overhead lines (8, 9) disposed on both sides and in the center of a vehicle (10) and measures the heights and deviations of the overhead lines (8, 9) through image processing using an image processing device (100) that uses stereo measurement of the images of the overhead lines (8, 9) imaged by the three line-sensor cameras (1, 2, 3), said line measurement device being characterized in that the line sensor camera (3) disposed in the center of the vehicle (10) has, as the imaging range thereof, the entirety of a range (E) in which a crossing line (9) is present as an overhead line and the line sensor cameras (1, 2) disposed on both sides of the vehicle (10) each have, as the imaging range thereof, a range of one half of the crossing line range (E) halved by a center line (C) of the vehicle (10).

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