GB1123607A - Electrical protection system - Google Patents

Electrical protection system

Info

Publication number
GB1123607A
GB1123607A GB50523/66A GB5052366A GB1123607A GB 1123607 A GB1123607 A GB 1123607A GB 50523/66 A GB50523/66 A GB 50523/66A GB 5052366 A GB5052366 A GB 5052366A GB 1123607 A GB1123607 A GB 1123607A
Authority
GB
United Kingdom
Prior art keywords
circuit
current
supervisory
earth
dummy
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
GB50523/66A
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.)
American District Telegraph Co
Original Assignee
American District Telegraph Co
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
Priority claimed from US516896A external-priority patent/US3401384A/en
Application filed by American District Telegraph Co filed Critical American District Telegraph Co
Publication of GB1123607A publication Critical patent/GB1123607A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/02—Monitoring continuously signalling or alarm systems
    • G08B29/06—Monitoring of the line circuits, e.g. signalling of line faults
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/02—Monitoring continuously signalling or alarm systems
    • G08B29/06—Monitoring of the line circuits, e.g. signalling of line faults
    • G08B29/08—Signalling of tampering with the line circuit

Abstract

1,123,607. Alarm systems. AMERICAN DISTRICT TELEGRAPH CO. 10 Nov., 1966 [28 Dec., 1965], No. 50523/66. Heading G4H. In a protective system of the kind in which protected premises 11 are connected to a central station 10, there are two lines 12-1, 12-2 to the central station and a supervisory circuit 13-1, 13-2 for each, each supervisory circuit having a source of current 22-1, 22-2 and current sensitive relays B1-1, G1-1, B1-2, G1-2 for detecting changes of supervisory current, protection circuits 14-1, 14-2 at the protected premises arranged to pass the supervisory current to earth 18 are connected to current sensitive relays 52-1, 52-2 having contacts 51-1, 51-2 each connected to the other protection circuit and arranged to alter its resistive value and cause an alarm indication. Each earth current relay causes the other protective circuit to give an alarm if a protection circuit is replaced by a dummy circuit using a separate earth. Instead of using two separate protection circuits, an existing protection circuit and a dummy circuit may be used. The dummy consists of variable resistors one or more of which are cut out by the operation _ of the earth current relay of the protection circuit. The dummy circuit has a supervisory circuit at the central station which responds to any change of resistance.
GB50523/66A 1965-12-28 1966-11-10 Electrical protection system Expired GB1123607A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US516896A US3401384A (en) 1965-12-28 1965-12-28 Monitoring apparatus and method for electrical protection systems
US05/540,147 USRE28692E (en) 1965-12-28 1975-01-10 Monitoring apparatus and method for electrical protection systems

Publications (1)

Publication Number Publication Date
GB1123607A true GB1123607A (en) 1968-08-14

Family

ID=27058985

Family Applications (1)

Application Number Title Priority Date Filing Date
GB50523/66A Expired GB1123607A (en) 1965-12-28 1966-11-10 Electrical protection system

Country Status (2)

Country Link
US (1) USRE28692E (en)
GB (1) GB1123607A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2130445A1 (en) * 1971-06-19 1972-12-21 Telefonbau & Normalzeit Gmbh Circuit arrangement for signal lines

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999053627A1 (en) 1998-04-10 1999-10-21 Chrimar Systems, Inc. Doing Business As Cms Technologies System for communicating with electronic equipment on a network

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA758263A (en) 1967-05-02 American District Telegraph Company Electrical protection system
CA447265A (en) 1948-03-16 E. Reagan Maurice Control system
CA616363A (en) 1961-03-14 American District Telegraph Company Intruder alarm system
DE732994C (en) * 1937-01-09 1943-03-17 Hans Teodor Nicou Electric alarm system
US2895125A (en) * 1954-12-09 1959-07-14 Patrick F Henry Electrical alarm system
US3139143A (en) * 1962-07-27 1964-06-30 Automatic Sprinkler Corp Fire protection system
US3133276A (en) * 1963-03-21 1964-05-12 Miller Peter Burglar alarm system
US3252156A (en) * 1963-09-18 1966-05-17 American District Telegraph Co Alarm annunciator including detection of breaks, grounds, and a break followed by a ground on a monitored line
US3254334A (en) * 1963-12-19 1966-05-31 American District Telegraph Co Electrical protection system utilizing reverse polarity line testing with unidirectional current devices having reverse breakdown characteristic

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2130445A1 (en) * 1971-06-19 1972-12-21 Telefonbau & Normalzeit Gmbh Circuit arrangement for signal lines

Also Published As

Publication number Publication date
USRE28692E (en) 1976-01-20

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