GB1234556A - Improvements in or relating to electrical circuit protection devices - Google Patents
Improvements in or relating to electrical circuit protection devicesInfo
- 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
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.
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)
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 |
-
0
- CA CA899457A patent/CA899457A/en not_active Expired
-
1968
- 1968-11-29 GB GB5683469A patent/GB1234556A/en not_active Expired
Cited By (3)
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 |