Title:
【発明の名称】漏電保護システム
Document Type and Number:
Japanese Patent JP3121570
Kind Code:
B2
Abstract:
PURPOSE:To increase safety by allowing a sensitivity current frequency characteristic of a rapid and highly sensitive leakage circuit breaker to fall below the threshold value stipulated by IEC479-2. CONSTITUTION:When a leakage current having a frequency higher than a commercial one, a rapid and highly sensitive leakage circuit breaker ELB4 cuts off its circuit since the value of the leakage current exceeds the sensitivity current value of the breaker ELB4. Medium sensitive leakage circuit breakers ELB1, ELB2 which are cascade-connected above another rapid and highly sensitive leakage circuit breaker ELB3 do not cut off their own circuits at that high frequency leakage current since the leakage current value does not reach the value of the sensitivity current of the breakers ELB1, ELB2 which has sharply risen. Therefore, a leakage current which exceeds the threshold value of IEC479-2 that is dangerous to human body is cut off and this grounding failure does not spread to the other devices as protection coordination is taken. Consequently, safety is increased.
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Inventors:
Yukio Suzuki
Hideki Hayakawa
Tomiyoshi Kiryu
Hiroshi Ikeda
Hideo Ishii
Wataru Teraoka
Hideki Hayakawa
Tomiyoshi Kiryu
Hiroshi Ikeda
Hideo Ishii
Wataru Teraoka
Application Number:
JP27268097A
Publication Date:
January 09, 2001
Filing Date:
October 06, 1997
Export Citation:
Assignee:
株式会社日立製作所
日立テクノエンジニアリング株式会社
日立テクノエンジニアリング株式会社
International Classes:
G01R31/02; H02H3/16; H02H3/33; H02H5/12; H02H7/30; (IPC1-7): H02H3/33; H02H3/16; H02H5/12
Domestic Patent References:
| JP61128719A | ||||
| JP50161653A | ||||
| JP1148015A |
Attorney, Agent or Firm:
Masami Akimoto