GB1234556A - Improvements in or relating to electrical circuit protection devices - Google Patents

Improvements in or relating to electrical circuit protection devices

Info

Publication number
GB1234556A
GB1234556A GB5683469A GB1234556DA GB1234556A GB 1234556 A GB1234556 A GB 1234556A GB 5683469 A GB5683469 A GB 5683469A GB 1234556D A GB1234556D A GB 1234556DA GB 1234556 A GB1234556 A GB 1234556A
Authority
GB
United Kingdom
Prior art keywords
circuit
transistor
current
responsive means
diodes
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
GB5683469A
Inventor
Alban Edward Harris
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.)
General Electric Co PLC
Original Assignee
General Electric Co PLC
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 General Electric Co PLC filed Critical General Electric Co PLC
Publication of GB1234556A publication Critical patent/GB1234556A/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
    • H02H3/08—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 excess current
    • H02H3/087—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 excess current for dc applications
    • 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
    • H02H3/02—Details
    • H02H3/025—Disconnection after limiting, e.g. when limiting is not sufficient or for facilitating disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
    • H02H9/026—Current limitation using PTC resistors, i.e. resistors with a large positive temperature coefficient

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Protection Of Static Devices (AREA)

Abstract

1,234,556. Protective arrangements. GENERAL ELECTRIC CO. Ltd. 1 Dec., 1969 [29 Nov., 1968], No. 56834/69. Divided out of 1,233,110. Heading H2K. A protective arrangement comprises a positive temperature coefficient thermistor T1 . . . T3 connected in series with a respective circuit C1 . . . C3 and means responsive to the increased voltage drop across a thermistor consequent upon an over-current in the respective circuit. The self-heating of the transistor causes it to pass through its transition temperature with rapid increase in resistance, the resulting increase in the voltage drop causing the operation of voltage responsive means to give an alarm or to initiate a control operation. The thermistors may perform a current-limiting function or may be shunted by resistors so that they carry a fraction of the working current. Diodes D1 . . . D3 provide isolation between the respective circuits and a switch S enables a defective circuit to be identified. In an alternative arrangement the voltage responsive means is connected across the circuits C1 . . . C3 and the diodes are forward biased under overload conditions by an auxiliary source having a potential exceeding that across a circuit C1 . . . C3 when overloaded. Fig. 3 (not shown) shows a voltage responsive means as comprising a lamp in series with a transistor and zener diode, the connection from the switch S being to the base of the transistor.
GB5683469A 1968-11-29 1968-11-29 Improvements in or relating to electrical circuit protection devices Expired GB1234556A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA899457T
GB5683469 1968-11-29

Publications (1)

Publication Number Publication Date
GB1234556A true GB1234556A (en) 1971-06-03

Family

ID=72178293

Family Applications (1)

Application Number Title Priority Date Filing Date
GB5683469A Expired GB1234556A (en) 1968-11-29 1968-11-29 Improvements in or relating to electrical circuit protection devices

Country Status (2)

Country Link
CA (1) CA899457A (en)
GB (1) GB1234556A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0404692A1 (en) * 1989-06-23 1990-12-27 SAT (Société Anonyme de Télécommunications) Protection device for a voltage source against short-circuits
GB2399958A (en) * 2003-03-26 2004-09-29 Jin Wu Decorative lighting circuit with overcurrent protection

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0404692A1 (en) * 1989-06-23 1990-12-27 SAT (Société Anonyme de Télécommunications) Protection device for a voltage source against short-circuits
FR2648963A1 (en) * 1989-06-23 1990-12-28 Telecommunications Sa PROTECTION DEVICE FOR A VOLTAGE SOURCE AGAINST SHORT-CIRCUITS
GB2399958A (en) * 2003-03-26 2004-09-29 Jin Wu Decorative lighting circuit with overcurrent protection

Also Published As

Publication number Publication date
CA899457A (en) 1972-05-02

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees