GB797672A - Improvements relating to balanced electrical protective apparatus - Google Patents
Improvements relating to balanced electrical protective apparatusInfo
- Publication number
- GB797672A GB797672A GB198255A GB198255A GB797672A GB 797672 A GB797672 A GB 797672A GB 198255 A GB198255 A GB 198255A GB 198255 A GB198255 A GB 198255A GB 797672 A GB797672 A GB 797672A
- Authority
- GB
- United Kingdom
- Prior art keywords
- relay
- coils
- coil
- contacts
- current
- 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
- H02H3/26—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
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
797,672. Protective cut-out systems. FERRANTI, Ltd. April 20, 1956 [Jan. 22, 1955], No. 1982/55. Class 38 (5). In a balanced protective system the three relay coils 11, 12, 13 in the separate phases are combined into one D.C. relay. Rectifiers 15, 16, 17 ensure that currents flow in these coils in one direction only and the rectifier 17 is reversed so that a force proportional to the current in the coil 13, which has twice as many turns but the same resistance as 11 or 12, is balanced against that of the other two coils. When the relay operates its contacts 18, 19 disconnect the load 14 and connect indicating lamps 21, 24 and resistors 23, 25 to phase C to hold the contacts in this position. A push switch 22 restores the relay to normal. In Fig. 2 the cores 26, 27 of a magnetic amplifier are each provided with six coils arranged for full-wave rectification and two control coils 28, 29 in a relay circuit so that saturation of the cores on unbalance reduces the impedance of coils 28, 29 and hence increases the current in one coil 49 of the relay 43, which opposes closing coil 54 for contacts 41, 42. The effect of increased current in the coil 49 is thus to open contacts 41, 42 which remain open until a start switch 46 is actuated. Additional windings 51 in the circuit of the coil 49 assist the winding sets 32 in phase B so as to equalize the sensitivity of the amplifier in the various conditions of unbalance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB198255A GB797672A (en) | 1955-01-22 | 1955-01-22 | Improvements relating to balanced electrical protective apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB198255A GB797672A (en) | 1955-01-22 | 1955-01-22 | Improvements relating to balanced electrical protective apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB797672A true GB797672A (en) | 1958-07-09 |
Family
ID=9731493
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB198255A Expired GB797672A (en) | 1955-01-22 | 1955-01-22 | Improvements relating to balanced electrical protective apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB797672A (en) |
-
1955
- 1955-01-22 GB GB198255A patent/GB797672A/en not_active Expired
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