GB727966A - Improvements in or relating to protective systems for electrical equipment - Google Patents
Improvements in or relating to protective systems for electrical equipmentInfo
- Publication number
- GB727966A GB727966A GB533951A GB533951A GB727966A GB 727966 A GB727966 A GB 727966A GB 533951 A GB533951 A GB 533951A GB 533951 A GB533951 A GB 533951A GB 727966 A GB727966 A GB 727966A
- Authority
- GB
- United Kingdom
- Prior art keywords
- contactor
- earthed
- coil
- earth
- casing
- 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
- 230000001681 protective effect Effects 0.000 title abstract 2
- 230000007935 neutral effect Effects 0.000 abstract 3
- 238000004804 winding Methods 0.000 abstract 3
- 230000004048 modification Effects 0.000 abstract 2
- 238000012986 modification Methods 0.000 abstract 2
- 239000004020 conductor Substances 0.000 abstract 1
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
- H02H3/16—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 fault current to earth, frame or mass
- H02H3/162—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 fault current to earth, frame or mass for AC systems
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
- H02H11/001—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of incorrect or interrupted earth connection
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Direct Current Feeding And Distribution (AREA)
Abstract
727,966. Protective cut-out arrangements. NALDER BROS. & THOMPSON, Ltd., SHEWAN, J. R., and ECKETT, S. W. March 21, 1952 [March 5, 1951], No. 5339/51. Class 38 (5). Normally-earthed electrical apparatus 2, e.g. a portable drill, is disconnected from supply terminals L, N by a contactor C', C', in the event of failure of the earth connection or if the apparatus winding becomes earthed. The contactor casing 1 is earthed at E and the earthed connection includes this point, a current trip coil IC, the secondary T1S of a transformer TI, an auxiliary relay CR, a pilot wire 5, the apparatus casing 2, a pilot wire 4 and the casing 1. The transformer primary TIP is connected across terminals L, N in parallel with a voltage trip coil VC through an auxiliary contact C' of the contactor, the circuit of coil VC including contacts C<SP>4</SP>, C<SP>5</SP> of relay CR. If the earth connection is interrupted, relay CR is de-energized and contacts C<SP>4</SP>, C' close to energize coil VC and open the contactor. If the apparatus winding is earthed, the excess current through coil IC opens the contactor. A non-linear impedance RI shunts the coils IC, CR and secondary TIS so that a voltage rise on the apparatus casing causes a decrease of the resistance of RI so as to delay any further voltage rise for a time, e.g. 0.05 secs., so that the contactor can open. In a modification (not shown) the winding TIP is connected between terminal L and the earth point E, the neutral N being earthed, so that if the earth at E fails, coil CR will be de-energized to open the contactor. In a further modification (not shown), the coil IC is connected between secondary TIS and the earthed neutral N, the contactor having further auxiliary contacts to control the earth circuit including the neutral conductor. According to a further arrangement, the end of coil IS is not connected directly to the earth point' E but is independently earthed elsewhere so as to include two earth points in the earth connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB533951A GB727966A (en) | 1951-03-05 | 1951-03-05 | Improvements in or relating to protective systems for electrical equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB533951A GB727966A (en) | 1951-03-05 | 1951-03-05 | Improvements in or relating to protective systems for electrical equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB727966A true GB727966A (en) | 1955-04-13 |
Family
ID=9794253
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB533951A Expired GB727966A (en) | 1951-03-05 | 1951-03-05 | Improvements in or relating to protective systems for electrical equipment |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB727966A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2922925A (en) * | 1957-03-13 | 1960-01-26 | Gerrard Michael Cornelius | Protective device for electrical circuits and apparatus |
| US3344313A (en) * | 1965-04-02 | 1967-09-26 | Electronic Safety Controls Inc | Load responsive ungrounded electrical distribution system |
| US3562588A (en) * | 1968-11-15 | 1971-02-09 | Felten & Guilleaume Schaltanl | Safety arrangement for nonstationary electrical appliances connected to grounded supply networks |
| US4083041A (en) * | 1974-12-16 | 1978-04-04 | Interroyal Corporation | Ground circuit monitor |
| GB2411300B (en) * | 2004-02-17 | 2007-07-18 | Goodwin Air Plasma Ltd | Earth connections for workpieces |
-
1951
- 1951-03-05 GB GB533951A patent/GB727966A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2922925A (en) * | 1957-03-13 | 1960-01-26 | Gerrard Michael Cornelius | Protective device for electrical circuits and apparatus |
| US3344313A (en) * | 1965-04-02 | 1967-09-26 | Electronic Safety Controls Inc | Load responsive ungrounded electrical distribution system |
| US3562588A (en) * | 1968-11-15 | 1971-02-09 | Felten & Guilleaume Schaltanl | Safety arrangement for nonstationary electrical appliances connected to grounded supply networks |
| US4083041A (en) * | 1974-12-16 | 1978-04-04 | Interroyal Corporation | Ground circuit monitor |
| GB2411300B (en) * | 2004-02-17 | 2007-07-18 | Goodwin Air Plasma Ltd | Earth connections for workpieces |
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