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公开(公告)号:US10809312B2
公开(公告)日:2020-10-20
申请号:US16462233
申请日:2017-11-16
Inventor: Tsuyoshi Ikushima , Tomokazu Nishigaki , Naoki Fukuo
IPC: G01R31/02 , G01R15/18 , G01R19/165 , G01R31/50 , H03K19/20
Abstract: A first decision unit of an AC leakage detection section outputs a first output signal with a signal level depending on the level of a corrected first voltage signal output from a correction unit relative to a first threshold value. An excitation unit of a DC leakage detection section applies, to an excitation coil, an excitation voltage having an excitation frequency. A DC component detection unit outputs a second voltage signal representing magnitude of a DC component of the voltage obtained by a current-detecting resistor. A second decision unit outputs a second output signal having a voltage level depending on the level of the second voltage signal relative to a second threshold value. The DC leakage detection section includes a low-pass filter provided between an input terminal electrically connected to a connection point between the excitation coil and the current-detecting resistor and the excitation coil.
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公开(公告)号:US11277001B2
公开(公告)日:2022-03-15
申请号:US16477501
申请日:2018-01-29
Inventor: Takashi Kawamoto , Takao Akioka , Naoki Fukuo , Shinichi Nakamura , Masahiko Kimura
Abstract: A body of a power feed control device includes a housing recess to house a module including a holder, the first sub-bus bar, the second sub-bus bar, the third sub-bus bar, and a zero-phase-sequence current transformer. Lengths of respective extended pieces of the first sub-bus bar, the second sub-bus bar, and the third sub-bus bar are different from each other. The holder includes a rod portion, a post portion, and an extended portion. The extended portion covers the respective extended pieces of the first sub-bus bar, the second sub-bus bar, and the third sub-bus bar.
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公开(公告)号:US10983174B2
公开(公告)日:2021-04-20
申请号:US16462226
申请日:2017-11-16
Inventor: Tsuyoshi Ikushima , Naoki Fukuo , Tomokazu Nishigaki
Abstract: An excitation unit applies, to an excitation coil, an excitation voltage with a voltage level alternately changing between a first high voltage value higher than a reference voltage value and a first low voltage value lower than the reference voltage value. The excitation unit includes a comparison circuit and a voltage switching circuit. The comparison circuit outputs a comparison signal having a voltage level switching between a high level and a low level depending on whether a detection voltage is greater than, or equal to or less than, a threshold voltage. The voltage switching circuit switches the voltage level of the excitation voltage between the first high voltage value and the first low voltage value according to the voltage level of the comparison signal.
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公开(公告)号:US10396544B2
公开(公告)日:2019-08-27
申请号:US15563934
申请日:2016-03-25
Inventor: Eiji Iwami , Tsuyoshi Ikushima , Naoki Fukuo , Tomokazu Nishigaki
Abstract: A magnetic core is electromagnetically coupled to two conductors that allow an AC current to flow through. An exciter is configured to supply a winding with an excitation current that is an alternating current. A current detector is configured to detect a current flowing through the winding. A DC component detector is configured to detect a DC component level from the current detected with the current detector. Two contact elements are respectively disposed along the two conductors. A discrimination controller is configured to: turn the two contact elements on when the DC component level detected with the DC component detector is less than or equal to a threshold; turn the two contact elements off when the DC component level detected with the DC component detector is greater than the threshold; and turn the two contact elements off in de-energized condition.
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公开(公告)号:US10367346B2
公开(公告)日:2019-07-30
申请号:US15501537
申请日:2015-02-26
Inventor: Naoki Fukuo , Koji Yamato , Hideki Kawahara
Abstract: The electric leakage protection device (feed control device includes an electric leakage detector, an electric leakage protector, and a self leakage generator. The electric leakage detector outputs an electric leakage detection signal when a current leaked from a main circuit exceeds a threshold value. The electric leakage protector opens a contact device interposed in the main circuit when receiving the electric leakage detection signal. The self leakage generator includes; a first short circuit having a first electric resistance component and a first switch component electrically connected in series with each other, and a second short circuit having a second electric resistance component and a second switch component electrically connected in series with each other. The first short circuit and the second short circuit are electrically connected in parallel with each other with regard to a pair of power supply paths constituting the main circuit.
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