Patents by Inventor Kado Miyakawa

Kado Miyakawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6288461
    Abstract: In order to provide an electric rotary machine in which the cooling performance can be improved without providing specific means on the flow path of cooling gas and without increasing the flow rate of the cooling gas, a plurality of through holes 21 perforated in each of plate-shaped conductors 16 forming a winding conductor 15 are arranged in plural rows of through holes 21a, 21b in the width direction of the plate-shaped conductor, a plurality of cooling gas flow paths 20 formed in the winding conductor 15 branch off into plural rows and the cooling area for the cooling gas is increased.
    Type: Grant
    Filed: October 29, 1999
    Date of Patent: September 11, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Hideaki Mori, Tadashi Sonobe, Kado Miyakawa, Hiroshi Kimoto, Takashi Shibata, Shingo Yokoyama
  • Patent number: 5559421
    Abstract: In a generator starting apparatus, in which commercial frequency electric power supplied from an electric power system is converted into variable-voltage variable-frequency electric power to thereby start a gas turbine generator, a harmonic-component removing apparatus is provided which removes harmonic components contained in the converted variable-voltage variable-frequency electric power on the basis of the detected harmonic components. In addition, an apparatus for removing harmonic components generated in an electric power equipment is provided, wherein harmonic components contained in an electric power system are detected so that they may be removed.
    Type: Grant
    Filed: March 4, 1994
    Date of Patent: September 24, 1996
    Assignee: Hitachi, Ltd.
    Inventor: Kado Miyakawa
  • Patent number: 5469009
    Abstract: The rotor 2 of a rotating field type turbine generator is provided with slots 3 for accommodating the field windings, wedges 4 positioned at the portions of the magnetic poles on the rotor 2 for holding the field windings and wedges 5 positioned between the magnetic poles on the rotor. These wedges 4 and 5 are constituted by metal bars without joints to enhance damper effect thereby. Magnetomotive forces due to higher harmonics, which causes temperature rise of the rotor 2 and torque ripple during starting with thyristors, induces an elliptic rotating magnetic field having the longer diameter on d axis extending in the direction of magnetomotive force induced by the field windings and the shorter diameter on q axis perpendicular to d axis, and thus a larger eddy current is induced flowing along q axis on the rotor 2 than that flowing along d axis.
    Type: Grant
    Filed: June 15, 1994
    Date of Patent: November 21, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Wakui, Kazumasa Ide, Haruo Koharagi, Miyoshi Takahashi, Kado Miyakawa, Yasuomi Yagi
  • Patent number: 5459363
    Abstract: The rotor for a dynamo electric machine serving as a synchronous generator as well as being designed operable as a variable speed motor for starting a prime mover for the synchronous generator, the rotor (1) comprising a rotor core (2), a plurality of slots (4) disposed around the circumference of the rotor core (2) and extending along the axial direction of the rotor core (2), rotor windings (3) being accommodated in the slots (4) and wedges (6) being accommodated in the slots (4) over the rotor windings (3) near at the surface of the rotor core (2) for preventing the rotor windings (3) from being pushed out due to a centrifugal force caused by rotation of the rotor (1), wherein wedges (6) where an eddy current flows are formed by Cu-0.05.about.4 wt % Zr-0.3.about.5 wt % Ni-0.2.about.1.5 wt % Si having a 0.2% proof stress equal to or more than about 20 Kg/mm.sup.
    Type: Grant
    Filed: October 20, 1994
    Date of Patent: October 17, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Kado Miyakawa, Takanobu Mori, Yasuomi Yagi, Fumio Shibata