GB866168A - Improvements in or relating to electrical alarm and indicator circuit systems - Google Patents
Improvements in or relating to electrical alarm and indicator circuit systemsInfo
- Publication number
- GB866168A GB866168A GB2020958A GB2020958A GB866168A GB 866168 A GB866168 A GB 866168A GB 2020958 A GB2020958 A GB 2020958A GB 2020958 A GB2020958 A GB 2020958A GB 866168 A GB866168 A GB 866168A
- Authority
- GB
- United Kingdom
- Prior art keywords
- switches
- relay
- contacts
- circuits
- polarity
- 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
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
- G08B29/12—Checking intermittently signalling or alarm systems
- G08B29/126—Checking intermittently signalling or alarm systems of annunciator circuits
Landscapes
- Engineering & Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
866,168. Protective arrangements. ASTRAL SWITCHGEAR Ltd. June 16, 1959 [June 24, 1958], No. 20209/58. Class 38 (5). In an alarm or indicator system having a number of separate alarm circuits fed from a common D.C. supply, a unidirectional device is located in each circuit such that reversal of polarity of the D.C. supply simulates the operation of control switches in all the circuits for test purposes. In each circuit the operation of a control switch S1, which may respond to a fault condition in associated apparatus, causes the energizing of a relay A/3 which momentarily closes contacts A-a to energize a common bell relay B/2. The bell relay closes contacts B-a, which with the now closed contacts A-b of the relay A/3, complete the circuit for a common alarm bell B. The closing of contacts A-b also cause the operation of a " flashing " relay C/2 so that the lamps l1 are flashed over contacts A-c. To test the circuits, the operation of a changeover switch S3 reverses the polarity of the supply from a D.C. source P. A rectifier R associated with each switch S1 is now able to conduct so simultating the operation of the switches and causing the operation of all the relays. Should the circuits be arranged for control by normally closed switches, the rectifiers are connected in series with the switches so that when the polarity is reversed, the rectifiers cease to conduct and simulate the opening of the switches.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2020958A GB866168A (en) | 1958-06-24 | 1958-06-24 | Improvements in or relating to electrical alarm and indicator circuit systems |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2020958A GB866168A (en) | 1958-06-24 | 1958-06-24 | Improvements in or relating to electrical alarm and indicator circuit systems |
Publications (1)
Publication Number | Publication Date |
---|---|
GB866168A true GB866168A (en) | 1961-04-26 |
Family
ID=10142229
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2020958A Expired GB866168A (en) | 1958-06-24 | 1958-06-24 | Improvements in or relating to electrical alarm and indicator circuit systems |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB866168A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3309685A (en) * | 1964-06-16 | 1967-03-14 | Standard Electric Time Co | Supervisory circuit |
US3345565A (en) * | 1965-08-27 | 1967-10-03 | Richard W Cotter | Continuity field test bridge circuit with diode-controlled visual indicator means |
-
1958
- 1958-06-24 GB GB2020958A patent/GB866168A/en not_active Expired
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3309685A (en) * | 1964-06-16 | 1967-03-14 | Standard Electric Time Co | Supervisory circuit |
US3345565A (en) * | 1965-08-27 | 1967-10-03 | Richard W Cotter | Continuity field test bridge circuit with diode-controlled visual indicator means |
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