GB987974A - Improvements in or relating to electrical protective relays - Google Patents
Improvements in or relating to electrical protective relaysInfo
- Publication number
- GB987974A GB987974A GB25283/60A GB2528360A GB987974A GB 987974 A GB987974 A GB 987974A GB 25283/60 A GB25283/60 A GB 25283/60A GB 2528360 A GB2528360 A GB 2528360A GB 987974 A GB987974 A GB 987974A
- Authority
- GB
- United Kingdom
- Prior art keywords
- relay
- capacitor
- transistor
- motor
- resistor
- 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
- H02H3/093—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 with timing means
-
- 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
- H02H3/26—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 difference between voltages or between currents; responsive to phase angle between voltages or between currents
- H02H3/32—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 difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
- H02H3/34—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 difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors of a three-phase system
- H02H3/343—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 difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors of a three-phase system using phase sequence analysers
Landscapes
- Protection Of Generators And Motors (AREA)
Abstract
987,974. Protective arrangements. ENGLISH ELECTRIC CO. Ltd. July 14, 1961 [July 20, 1960], No. 25283/60. Heading H2K. [Also in Division H3] A polyphase time-overcurrent relay arrangement, e.g. for an induction motor RL, comprises a phase sequence filter, rectifiers Bp, Bn and a series-parallel resistance network R7 . . . R9 for deriving a unidirectional relay operating current dependent on a combination of the positive and negative phase sequence components of the current taken by the motor. When a capacitor C3 is charged by the relay operating current to a predetermined value, the transistor amplifier T2, T3 of Specification 958,774 energizes a protective relay AUX. The charging of the capacitor C3 is controlled by a transistor T1 which under normal load conditions is conducting, due to a positive bias applied to its base by means of resistors R15 ... R17, and permits the capacitor to acquire a standing charge dependent on the voltage across a resistor R14 and a diode D3 in series with the transistor T1. When an overload occurs, a sufficiently high negative potential exists across a resistor R11 and diode D1 to stop the transistor T1 conducting and the capacitor C3 is charged fully by the relay operating current to effect operation of the relay AUX. When the motor is switched off, any charge in the capacitor C3 is slowly discharged through a diode D4 and a resistor P6 providing a long time reset. Thus should an overload fault condition exist when the motor is first switched on, the transistor T1 does not conduct and as the capacitor has no standing charge, a longer time elapses before relay operation occurs. Thus the relay arrangement provides " hot " and " cold " characteristics similar to those of a thermal overload relay.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB25283/60A GB987974A (en) | 1960-07-20 | 1960-07-20 | Improvements in or relating to electrical protective relays |
FR868566A FR1303031A (en) | 1960-07-20 | 1961-07-20 | Protection relay systems |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB25283/60A GB987974A (en) | 1960-07-20 | 1960-07-20 | Improvements in or relating to electrical protective relays |
FR868566A FR1303031A (en) | 1960-07-20 | 1961-07-20 | Protection relay systems |
Publications (1)
Publication Number | Publication Date |
---|---|
GB987974A true GB987974A (en) | 1965-03-31 |
Family
ID=68621071
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB25283/60A Expired GB987974A (en) | 1960-07-20 | 1960-07-20 | Improvements in or relating to electrical protective relays |
Country Status (2)
Country | Link |
---|---|
FR (1) | FR1303031A (en) |
GB (1) | GB987974A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2306569A1 (en) * | 1975-04-01 | 1976-10-29 | Gen Electric | FILTER FOR SYMMETRICAL COMPONENTS AND DEVICE INCORPORATING SUCH FILTERS |
-
1960
- 1960-07-20 GB GB25283/60A patent/GB987974A/en not_active Expired
-
1961
- 1961-07-20 FR FR868566A patent/FR1303031A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2306569A1 (en) * | 1975-04-01 | 1976-10-29 | Gen Electric | FILTER FOR SYMMETRICAL COMPONENTS AND DEVICE INCORPORATING SUCH FILTERS |
Also Published As
Publication number | Publication date |
---|---|
FR1303031A (en) | 1962-09-07 |
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