Title:
GROUNDING CURRENT DETECTOR
Document Type and Number:
Japanese Patent JP3425004
Kind Code:
B2
Abstract:
PURPOSE: To open a circuit breaker immediately if grounding exists when the circuit breaker is closed.
CONSTITUTION: An alternating current from an AC line is rectified by a diode D3 and smoothed by a capacitor C3. A starter circuit 6 is provided between a ground current judgment circuit 2 which decides the existence of grounding in accordance with the detected voltage of a zero-phase current transformer ZCT and the capacitor C3. The starter circuit 6 has a transistor which is provided between the capacitor C3 and the power supply terminal Vcc of the ground current judgment circuit 2 and the transistor is held at an OFF-state until a voltage between both terminals of the capacitor C3 reaches the operation voltage of the ground current judgment circuit 2. Therefore, the charge in the capacitor C3 is not consumed until the capacitor C3 is sufficiently charged and hence the voltage between both terminals of the capacitor C3 can be made to rise quickly.
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Inventors:
Masataka Kanda
Hitoshi Makinaga
Yasuo Nagai
Tsukui Yuji
Hitoshi Makinaga
Yasuo Nagai
Tsukui Yuji
Application Number:
JP9556395A
Publication Date:
July 07, 2003
Filing Date:
April 20, 1995
Export Citation:
Assignee:
松下電工株式会社
株式会社日立製作所
株式会社日立超エル・エス・アイ・システムズ
株式会社日立製作所
株式会社日立超エル・エス・アイ・システムズ
International Classes:
H02H3/347; H02H3/34; (IPC1-7): H02H3/347; H02H3/34
Domestic Patent References:
| JP438116A | ||||
| JP54129447A | ||||
| JP6133447A |
Attorney, Agent or Firm:
Keisei Nishikawa (1 person outside)