GB1345869A - Electrical current measuring instruments - Google Patents
Electrical current measuring instrumentsInfo
- Publication number
- GB1345869A GB1345869A GB1345869DA GB1345869A GB 1345869 A GB1345869 A GB 1345869A GB 1345869D A GB1345869D A GB 1345869DA GB 1345869 A GB1345869 A GB 1345869A
- Authority
- GB
- United Kingdom
- Prior art keywords
- current
- line
- taps
- transistors
- core
- 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
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/18—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using conversion of DC into AC, e.g. with choppers
- G01R19/20—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using conversion of DC into AC, e.g. with choppers using transductors, i.e. a magnetic core transducer the saturation of which is cyclically reversed by an AC source on the secondary side
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Resistance Or Impedance (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
1345869 Measuring direct current DEFENCE SECRETARY OF STATE FOR 30 Nov 1971 [30 Nov 1970] 56771/70 Heading G1U In order to measure the direct current i 3 , Fig. 5, through a line L 3 , a magnetic core M is cyclically driven around its hysterisis loop by a multivibrator comprising transistors Q 1 , Q 2 , and oppositely wound coils L 1 , L 2 , and the difference in the average currents through the two transistors Q 1 , Q 2 , is measured, this being a measure of the unknown current i 3 . This arises because in the absence of current i 3 in the line L 3 , a potentiometer RV is adjusted so that the conduction pattern of the transistors Q 1 , Q 2 is symmetrical, and therefore a voltmeter R5, A, reads zero, whereas once a current i 3 is present the conduction pattern becomes asymmetrical to an extent which is proportional to i 3 . In a modification, rather than the asymmetry being determined by an averaging-volt meter R5, A, a voltage representing the asymmetry is derived by a filter F and an amplifier Da, Fig. 7, and used to apply a compensating current i 4 to the core in a direction which opposes i 3 . In a further modification Fig. 6, (not shown), an additional core (M') is coupled to the line L 3 and windings on it are energized in such a way as to cancel signals induced in the line by the main core. Range changing may be effected either by taps on the coils L 1 , L 2 , Fig. 5, Fig. 7, (the taps not being shown) or by taps on the compensating winding.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB5677170 | 1971-11-30 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1345869A true GB1345869A (en) | 1974-02-06 |
Family
ID=10477501
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1345869D Expired GB1345869A (en) | 1971-11-30 | 1971-11-30 | Electrical current measuring instruments |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB1345869A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2339247A1 (en) * | 1976-01-23 | 1977-08-19 | Siemens Ag | CIRCUIT BREAKER |
FR2458165A1 (en) * | 1979-05-31 | 1980-12-26 | Merlin Gerin | Static inverter ground fault protection - using differential and DC level toroid detection transformers |
FR2533317A1 (en) * | 1982-09-17 | 1984-03-23 | Inst Komplektnogo Elektropri | Apparatus for measuring the instantaneous value of a current |
EP0137347A1 (en) * | 1983-09-15 | 1985-04-17 | Danfysik A/S | A detector circuit for current measurements |
CN102866283A (en) * | 2012-09-12 | 2013-01-09 | 北京东方计量测试研究所 | Superimposed large-current bias alternative-current (AC) current measuring device |
-
1971
- 1971-11-30 GB GB1345869D patent/GB1345869A/en not_active Expired
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2339247A1 (en) * | 1976-01-23 | 1977-08-19 | Siemens Ag | CIRCUIT BREAKER |
FR2458165A1 (en) * | 1979-05-31 | 1980-12-26 | Merlin Gerin | Static inverter ground fault protection - using differential and DC level toroid detection transformers |
FR2533317A1 (en) * | 1982-09-17 | 1984-03-23 | Inst Komplektnogo Elektropri | Apparatus for measuring the instantaneous value of a current |
EP0137347A1 (en) * | 1983-09-15 | 1985-04-17 | Danfysik A/S | A detector circuit for current measurements |
CN102866283A (en) * | 2012-09-12 | 2013-01-09 | 北京东方计量测试研究所 | Superimposed large-current bias alternative-current (AC) current measuring device |
CN102866283B (en) * | 2012-09-12 | 2015-05-20 | 北京东方计量测试研究所 | Superimposed large-current bias alternative-current (AC) current measuring device |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |