Patents by Inventor Naohiro Takakamo

Naohiro Takakamo 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: 7353123
    Abstract: A measurement method is disclosed for measuring the resistance component leakage current. The signal waveform of at least one AC cycle is sampled in the resistance component leakage current measurement, and the resistance component leakage current is measured. A zero-cross detecting circuit for detecting a voltage zero-crossing point of the target measurement circuit and outputting a sampling start signal is provided, voltage digital data of the sine wave form whose effective value is 1 and the output signal of the zero-phase current transformer are sampled, and the products of multiplication are averaged by synchronizing the sampled output signal value and the voltage digital data to obtain an active leakage component current of leakage currents.
    Type: Grant
    Filed: July 11, 2005
    Date of Patent: April 1, 2008
    Assignee: Hitachi, Ltd.
    Inventors: Naohiro Takakamo, Sakai Kuniyoshi, Nobuyuki Kawauchi
  • Patent number: 7161354
    Abstract: A method for measuring the resistance component current included in the leakage current is provided. In a monitoring apparatus and system for measurement the signal waveform of at least one AC cycle is sampled. The resistance component leakage current is measured by dividing the average of integrated value of the instantaneous leakage current values and the instantaneous voltage values by the square root of average of squared instantaneous voltage values. In addition, a voltage signal of the target measurement circuit is obtained the waveform of the leakage current signal and the voltage signal for one cycle is sampled and stored; the leakage current signal and the voltage signal are expanded to N-th higher harmonic wave component respectively, and the resistance component that relates to the leakage current is calculated.
    Type: Grant
    Filed: March 23, 2005
    Date of Patent: January 9, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Naohiro Takakamo, Kuniyoshi Sakai, Yoshikazu Terakami
  • Patent number: 7110895
    Abstract: A method for measuring the resistance component current included in the leakage current is provided. In a monitoring apparatus and system for measurement the signal waveform of at least one AC cycle is sampled. The resistance component leakage current is measured by dividing the average of integrated value of the instantaneous leakage current values and the instantaneous voltage values by the square root of average of squared instantaneous voltage values. In addition, a voltage signal of the target measurement circuit is obtained the waveform of the leakage current signal and the voltage signal for one cycle is sampled and stored; the leakage current signal and the voltage signal are expanded to N-th higher harmonic wave component respectively, and the resistance component that relates to the leakage current is calculated.
    Type: Grant
    Filed: October 4, 2002
    Date of Patent: September 19, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Naohiro Takakamo, Kuniyoshi Sakai, Yoshikazu Terakami
  • Publication number: 20060020406
    Abstract: A measurement method is disclosed for measuring the resistance component leakage current included in the leakage current and the resistance value that is an insulation resistance to monitor the insulation state of a distribution system. The signal waveform of at least one AC cycle is sampled in the resistance component leakage current measurement from the leakage current signal and the voltage signal of a current transformer of target measurement circuit, and the resistance component leakage current is measured by dividing the average of integrated value of the instantaneous leakage current values and the instantaneous voltage values by the square root of average of squared instantaneous voltage values.
    Type: Application
    Filed: July 11, 2005
    Publication date: January 26, 2006
    Applicant: Hitachi, Ltd.
    Inventors: Naohiro Takakamo, Kuniyoshi Sakai, Yoshikazu Terakami, Nobuyuki Kawauchi
  • Publication number: 20050225909
    Abstract: The system makes it possible to monitor various electrical variables by using a simple structure at low cost with ease and with high reliability by a circuit breaker which jointly includes a current transformer to detect current, a transformer to detect voltage, and a zero-phase current transformer to detect leakage current, in addition to the switch controller to perform the basic function of the circuit breaker. Moreover, the system also provides a function to display various measured values, obtained as described above, by a display unit that can be detached and installed separately from the measuring section to display data sent in digital form by data transmission.
    Type: Application
    Filed: August 18, 2004
    Publication date: October 13, 2005
    Applicant: Hitachi Industrial Equipment Co., Ltd.
    Inventors: Akio Yoshizaki, Naohiro Takakamo, Satoko Gotou, Hideki Hayakawa, Tetsunori Watanabe, Haruki Shibuya
  • Publication number: 20050200364
    Abstract: A method for measuring the resistance component current included in the leakage current is provided. In a monitoring apparatus and system for measurement the signal waveform of at least one AC cycle is sampled. The resistance component leakage current is measured by dividing the average of integrated value of the instantaneous leakage current values and the instantaneous voltage values by the square root of average of squared instantaneous voltage values. In addition, a voltage signal of the target measurement circuit is obtained the waveform of the leakage current signal and the voltage signal for one cycle is sampled and stored; the leakage current signal and the voltage signal are expanded to N-th higher harmonic wave component respectively, and the resistance component that relates to the leakage current is calculated.
    Type: Application
    Filed: March 23, 2005
    Publication date: September 15, 2005
    Applicant: Hitachi, Ltd.
    Inventors: Naohiro Takakamo, Kuniyoshi Sakai, Yoshikazu Terakami
  • Patent number: 6922643
    Abstract: A method for measuring the resistance component current included in the leakage current is provided. In a monitoring apparatus and system for measurement the signal waveform of at least one AC cycle is sampled. The resistance component leakage current is measured by dividing the average of integrated value of the instantaneous leakage current values and the instantaneous voltage values by the square root of average of squared instantaneous voltage values. In addition, a voltage signal of the target measurement circuit is obtained the waveform of the leakage current signal and the voltage signal for one cycle is sampled and stored; the leakage current signal and the voltage signal are expanded to N-th higher harmonic wave component respectively, and the resistance component that relates to the leakage current is calculated.
    Type: Grant
    Filed: May 27, 2004
    Date of Patent: July 26, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Naohiro Takakamo, Kuniyoshi Sakai, Yoshikazu Terakami
  • Publication number: 20040220759
    Abstract: A method for measuring the resistance component current included in the leakage current is provided. In a monitoring apparatus and system for measurement the signal waveform of at least one AC cycle is sampled. The resistance component leakage current is measured by dividing the average of integrated value of the instantaneous leakage current values and the instantaneous voltage values by the square root of average of squared instantaneous voltage values. In addition, a voltage signal of the target measurement circuit is obtained the waveform of the leakage current signal and the voltage signal for one cycle is sampled and stored; the leakage current signal and the voltage signal are expanded to N-th higher harmonic wave component respectively, and the resistance component that relates to the leakage current is calculated.
    Type: Application
    Filed: May 27, 2004
    Publication date: November 4, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Naohiro Takakamo, Kuniyoshi Sakai, Yoshikazu Terakami
  • Publication number: 20030112015
    Abstract: A method for measuring the resistance component current included in the leakage current is provided. In a monitoring apparatus and system for measurement the signal waveform of at least one AC cycle is sampled. The resistance component leakage current is measured by dividing the average of integrated value of the instantaneous leakage current values and the instantaneous voltage values by the square root of average of squared instantaneous voltage values. In addition, a voltage signal of the target measurement circuit is obtained the waveform of the leakage current signal and the voltage signal for one cycle is sampled and stored; the leakage current signal and the voltage signal are expanded to N-th higher harmonic wave component respectively, and the resistance component that relates to the leakage current is calculated.
    Type: Application
    Filed: October 4, 2002
    Publication date: June 19, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Naohiro Takakamo, Kuniyoshi Sakai, Yoshikazu Terakami