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
Application number
GB27405/30A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
British Thomson Houston Co Ltd
Original Assignee
British Thomson Houston Co Ltd
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Publication date
Application filed by British Thomson Houston Co LtdfiledCriticalBritish Thomson Houston Co Ltd
Publication of GB365139ApublicationCriticalpatent/GB365139A/en
G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
G01R5/00—Instruments for converting a single current or a single voltage into a mechanical displacement
G01R5/14—Moving-iron instruments
Landscapes
Physics & Mathematics
(AREA)
General Physics & Mathematics
(AREA)
Reciprocating, Oscillating Or Vibrating Motors
(AREA)
Abstract
365,139. Current and pressure meters. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of St. Clair, B. W. ; 18, Verona Street, Lynn, Massachusetts, U.S.A.) Sept. 13, 1930, No. 27405. Convention date, Sept. 13, 1929. [Class 37.] An alternating-current ammeter or voltmeter is compensated for frequency variations by providing the polepiece structure with a shunt path for the magnetic flux in parallel with the main flux path, the shunt path having an air-gap and being surrounded by a shortcircuited coil. As shown, an alternating- current ammeter of the moving-vane type has auxiliary polepieces 14, 15 provided with short-circuited coils 16, the arrangement being such that as the frequency increases the total flux decreases but the torque-producing flux is increased owing to the increased reluctance of the shunt flux path. Damping is effected by a vane 27 movable across symmetrically disposed poles 25 of a permanent magnet.
GB27405/30A1929-09-131930-09-13Improvements in and relating to electric measuring instruments
ExpiredGB365139A
(en)