GB701941A - Improvements relating to electrical measuring instruments - Google Patents

Improvements relating to electrical measuring instruments

Info

Publication number
GB701941A
GB701941A GB1787851A GB1787851A GB701941A GB 701941 A GB701941 A GB 701941A GB 1787851 A GB1787851 A GB 1787851A GB 1787851 A GB1787851 A GB 1787851A GB 701941 A GB701941 A GB 701941A
Authority
GB
United Kingdom
Prior art keywords
range
relays
shunt
ammeter
closes
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
Application number
GB1787851A
Inventor
Michael Crowle Crowley-Milling
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.)
Metropolitan Vickers Electrical Co Ltd
Original Assignee
Metropolitan Vickers Electrical Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Metropolitan Vickers Electrical Co Ltd filed Critical Metropolitan Vickers Electrical Co Ltd
Priority to GB1787851A priority Critical patent/GB701941A/en
Publication of GB701941A publication Critical patent/GB701941A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H02H11/006—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of too high or too low voltage
    • H02H11/007—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of too high or too low voltage involving automatic switching for adapting the protected apparatus to the supply voltage
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/002—Switches for altering the measuring range or for multitesters

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)

Abstract

701,941. Ammeters and voltmeters. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. July 14, 1952 [Ju]y 27, 1951], No. 17878/51. Class 37 In an instrument operable over more than one range means independent of the indicating element are provided for automatically changing from a lower to a higher range when the quantity being measured exceeds a predetermined maximum value for the lower range, together with means for indicating the range for which the instrument is set. An ammeter AM and the operating coils A, B of two relays are connected in series between terminals x. These relays are set so that while the current remains below a predetermined maximum value for the low range they remain unoperated and the ammeter is not shunted. When this current is exceeded relay A operates and closes its contact a1 to connect a shunt S1 across the ammeter AM. When the current exceeds the predetermined value for the medium range relay B operates and closes its contacts b1 to connect a shunt S2 in parallel with the shunt S1 and also closes a contact b3 to connect a shunt R across the relay A to prevent overloading while maintaining it energized. The relays A, B also control the circuits of lamps indicating the range in use. As applied to a voltmeter, relays insert series resistances for the different ranges. In a modification the relays are connected in the anode circuits of thermionic valves, the grid voltage being arranged to be proportional to the quantity being measured.
GB1787851A 1951-07-27 1951-07-27 Improvements relating to electrical measuring instruments Expired GB701941A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1787851A GB701941A (en) 1951-07-27 1951-07-27 Improvements relating to electrical measuring instruments

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1787851A GB701941A (en) 1951-07-27 1951-07-27 Improvements relating to electrical measuring instruments

Publications (1)

Publication Number Publication Date
GB701941A true GB701941A (en) 1954-01-06

Family

ID=10102793

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1787851A Expired GB701941A (en) 1951-07-27 1951-07-27 Improvements relating to electrical measuring instruments

Country Status (1)

Country Link
GB (1) GB701941A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1039627B (en) * 1955-03-28 1958-09-25 Radio Patents Company Circuit arrangement for electrical measuring instruments u. Like. For automatic area selection
US3016488A (en) * 1960-11-08 1962-01-09 Rodale Electronics Inc Automatic range selector
US3052844A (en) * 1959-08-20 1962-09-04 Gen Motors Corp Double scale phase meter
DE1138559B (en) * 1955-09-13 1962-10-25 Metrawatt Ag Device for recording a measurement variable that changes over at least two partial measurement areas that almost encompass the entire writing area of the recording device
DE1140718B (en) * 1959-12-02 1962-12-06 Gossen & Co Gmbh P Light contact instrument with an upper and a lower switching point in the pointer deflection area associated with photo resistors
DE1244024B (en) * 1962-06-29 1967-07-06 Deutsche Telephonwerk Kabel Circuit arrangement for the automatic setting and setting of a measuring range of electrical current and voltage measuring devices in telecommunication and remote measuring systems
DE1266877B (en) * 1964-03-03 1968-04-25 Continental Elektro Ind Ag Device for monitoring several measuring points

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1039627B (en) * 1955-03-28 1958-09-25 Radio Patents Company Circuit arrangement for electrical measuring instruments u. Like. For automatic area selection
DE1138559B (en) * 1955-09-13 1962-10-25 Metrawatt Ag Device for recording a measurement variable that changes over at least two partial measurement areas that almost encompass the entire writing area of the recording device
US3052844A (en) * 1959-08-20 1962-09-04 Gen Motors Corp Double scale phase meter
DE1140718B (en) * 1959-12-02 1962-12-06 Gossen & Co Gmbh P Light contact instrument with an upper and a lower switching point in the pointer deflection area associated with photo resistors
US3016488A (en) * 1960-11-08 1962-01-09 Rodale Electronics Inc Automatic range selector
DE1244024B (en) * 1962-06-29 1967-07-06 Deutsche Telephonwerk Kabel Circuit arrangement for the automatic setting and setting of a measuring range of electrical current and voltage measuring devices in telecommunication and remote measuring systems
DE1266877B (en) * 1964-03-03 1968-04-25 Continental Elektro Ind Ag Device for monitoring several measuring points

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