GB565134A - Improvements in or relating to protective arrangements for electrical circuits - Google Patents

Improvements in or relating to protective arrangements for electrical circuits

Info

Publication number
GB565134A
GB565134A GB6564/43A GB656443A GB565134A GB 565134 A GB565134 A GB 565134A GB 6564/43 A GB6564/43 A GB 6564/43A GB 656443 A GB656443 A GB 656443A GB 565134 A GB565134 A GB 565134A
Authority
GB
United Kingdom
Prior art keywords
relay
thermistor
resistance element
series
resistance
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
GB6564/43A
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.)
STC PLC
Original Assignee
Standard Telephone and Cables 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 Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Publication of GB565134A publication Critical patent/GB565134A/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
    • H02H3/085—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 making use of a thermal sensor, e.g. thermistor, heated by the excess current

Landscapes

  • Emergency Protection Circuit Devices (AREA)
  • Control Of Electrical Variables (AREA)

Abstract

565,134. Protective cut-out arrangements. STANDARD TELEPHONES & CABLES, Ltd., SCULLY, C. T., and HOUGHTON, L. W. April 23, 1943, No. 6564. [Class 38 (v)] The inverse time-limit feature of an overload relay is derived from a thermistor, the properties of which are described in Bell Laboratories' Record, Vol. XIX, p. 106. In a simple form, Fig. 1 (not shown), the relay is energized in series with a negative temperature-coefficient resistance element of the thermistor from a current transformer in the line, or if a thermistor having a resistance element of positive temperature coefficient is employed, the relay and resistance are in parallel. The response characteristics may be varied by additional series or parallel resistance, or by employing a heater connected to an adjustable and independent source. In Fig. 2, a negative temperaturecoefficient thermistor T2 has its resistance element R2 connected in series with relay RY to a source S, and its heater r2 connected to the line current-transformer CT. To control the operating current of the relay, constantload attenuators A1, A2 are included in the respective circuits, but instead of employing A2, the relay may itself be made adjustable. The relay may be of the slow-release type so as to reclose the breaks automatically after a timedelay, or arranged to be locked out after one or more operations. The Specification discusses the effects of ambient temperature and refers to time-grading in " distance " protection. Specification 251,275, [Class 37], is referred to.
GB6564/43A 1943-04-23 1943-04-23 Improvements in or relating to protective arrangements for electrical circuits Expired GB565134A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB252220X 1943-04-23

Publications (1)

Publication Number Publication Date
GB565134A true GB565134A (en) 1944-10-27

Family

ID=10224178

Family Applications (1)

Application Number Title Priority Date Filing Date
GB6564/43A Expired GB565134A (en) 1943-04-23 1943-04-23 Improvements in or relating to protective arrangements for electrical circuits

Country Status (4)

Country Link
BE (1) BE472807A (en)
CH (1) CH252220A (en)
FR (1) FR942456A (en)
GB (1) GB565134A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2914747A (en) * 1953-01-30 1959-11-24 Bell Telephone Labor Inc Lockout circuits utilizing thermistor-gas tube combinations
US3002128A (en) * 1957-08-29 1961-09-26 Gen Electric Overload protective means for electrical apparatus

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2802059A (en) * 1954-07-08 1957-08-06 Bell Telephone Labor Inc Telephone ring-up circuit
FR2210000B1 (en) * 1972-12-13 1976-01-30 Saparel Fr

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2914747A (en) * 1953-01-30 1959-11-24 Bell Telephone Labor Inc Lockout circuits utilizing thermistor-gas tube combinations
US3002128A (en) * 1957-08-29 1961-09-26 Gen Electric Overload protective means for electrical apparatus

Also Published As

Publication number Publication date
FR942456A (en) 1949-02-09
CH252220A (en) 1947-12-15
BE472807A (en)

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