GB980415A - Improvements relating to earth leakage protective systems - Google Patents

Improvements relating to earth leakage protective systems

Info

Publication number
GB980415A
GB980415A GB718862A GB718862A GB980415A GB 980415 A GB980415 A GB 980415A GB 718862 A GB718862 A GB 718862A GB 718862 A GB718862 A GB 718862A GB 980415 A GB980415 A GB 980415A
Authority
GB
United Kingdom
Prior art keywords
transformer
current
relay
transistor
contactor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB718862A
Inventor
Harold Townley Baldwin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Baldwin & Francis Ltd
Original Assignee
Baldwin & Francis Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Baldwin & Francis Ltd filed Critical Baldwin & Francis Ltd
Priority to GB718862A priority Critical patent/GB980415A/en
Publication of GB980415A publication Critical patent/GB980415A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
    • H02H3/32—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
    • H02H3/34—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors of a three-phase system
    • H02H3/347—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors of a three-phase system using summation current transformers

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

980,415. Protective arrangements. BALDWIN & FRANCIS Ltd. May 20, 1963 [Feb. 23, 1962], No. 7188/62. Heading H2K. [Also in Division H3] An earth-leakage protective system for a polyphase apparatus M comprises a corebalance transformer CBT having an auxiliary primary winding 11 connected to an A.C. source 13 having a frequency which is relatively high with respect to the mains frequency, the secondary winding 12 of the transformer CBT controlling a transistor T which controls the current in the primary winding of an auxiliary transformer 21 having a secondary winding 22 connected to a relay R controlling a main contactor 4, 5. In the absence of an earth fault, the coupling between the windings 11, 12 provides a high frequency control current to the transistor T which provides a high frequency output. This output is amplified at 20, transformed at 21, rectified at 23 and energizes the relay R so that the contactor energizing circuit is closed by the contacts 6 of the relay R. When an earth fault occurs, a current of main frequency is induced in the secondary winding 12 of the transformer CBT and this current causes the transistor to be alternatively cut-off and overdriven so suppressing the high frequency component from the output of the transistor T. The auxiliary transformer 21 presents a much lower impedance to the mains frequency current and its output voltage comes insufficient to maintain the relay R fully energized so that contacts 6 open to open the contactor. The Provisional Specification refers to the provision of lock-out protection when the contactor is open, by injecting a small A.C. current through the fault path, the injection circuit including a further auxiliary winding on the core-balance transformer.
GB718862A 1962-02-23 1962-02-23 Improvements relating to earth leakage protective systems Expired GB980415A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB718862A GB980415A (en) 1962-02-23 1962-02-23 Improvements relating to earth leakage protective systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB718862A GB980415A (en) 1962-02-23 1962-02-23 Improvements relating to earth leakage protective systems

Publications (1)

Publication Number Publication Date
GB980415A true GB980415A (en) 1965-01-13

Family

ID=9828302

Family Applications (1)

Application Number Title Priority Date Filing Date
GB718862A Expired GB980415A (en) 1962-02-23 1962-02-23 Improvements relating to earth leakage protective systems

Country Status (1)

Country Link
GB (1) GB980415A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2555303A1 (en) * 1975-12-09 1977-06-23 Bbc Brown Boveri & Cie Fault current protective circuit - has summator transformer and has auxiliary windings feeding biasing generator and RC control
US4216516A (en) * 1978-10-26 1980-08-05 General Electric Company Portable ground fault protector

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2555303A1 (en) * 1975-12-09 1977-06-23 Bbc Brown Boveri & Cie Fault current protective circuit - has summator transformer and has auxiliary windings feeding biasing generator and RC control
US4216516A (en) * 1978-10-26 1980-08-05 General Electric Company Portable ground fault protector

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