GB647050A - Improvements in or relating to electrical protective arrangements - Google Patents

Improvements in or relating to electrical protective arrangements

Info

Publication number
GB647050A
GB647050A GB2820048A GB2820048A GB647050A GB 647050 A GB647050 A GB 647050A GB 2820048 A GB2820048 A GB 2820048A GB 2820048 A GB2820048 A GB 2820048A GB 647050 A GB647050 A GB 647050A
Authority
GB
United Kingdom
Prior art keywords
current
phase
resistor
pairs
transformers
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
GB2820048A
Inventor
Thomas Robert Rayner
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.)
Automatic Telephone and Electric Co Ltd
Original Assignee
Automatic Telephone and Electric 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 Automatic Telephone and Electric Co Ltd filed Critical Automatic Telephone and Electric Co Ltd
Priority to GB2820048A priority Critical patent/GB647050A/en
Publication of GB647050A publication Critical patent/GB647050A/en
Expired legal-status Critical Current

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
    • H02H3/44—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 the rate of change of electrical quantities

Landscapes

  • Emergency Protection Circuit Devices (AREA)

Abstract

647,050. Protective cut-out systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd. Oct. 30, 1948, No. 28200. [Class 38 (v)] In an arrangement for controlling the switching-in of phasecomparison equipment of the carriercurrent, lock-in type, means is provided for detecting a fault in cases where the maximum permissible load under some conditions is greater than the three - phase fault current in other conditions. For this purpose, potentials dependent on the currents in the different phases are balanced in pairs, so that if the difference potential of any pair is sufficiently great, the control relays operate. Three current transformers RT, YT, BT supply the primaries of six transformers RF1, RF2, YF1, YF2, BF1, BF2 over a summation transformer SCT, the secondary outputs being rectified by bridges RR1, RR2, YR1, YR2, BR1, BR2, the outputs of which are connected to resistors RA1, RC2, RB1, RA2, RC1, RB2, respectively. Normally, the voltages in the pairs of resistors RA1, RA2, RB1, RB2 and RC1, RC2 balance and the control relays LS, HS are de-energized. On lack of balance, due, e.g. to a single-phase fault, one or other of the resistor pairs will be unbalanced and the relays will operate. One resistor of each pair is shunted by a condenser QA-QC so that on a sudden increase of current, the voltage across that resistor will build up more slowly than the other, so that operation will ensue. The secondaries of the transformers RF1 &c. are shunted by non-linear resistors RN1, RN2, YN1, YN2, BN1, BN2, the characteristics of which are different for the two members of a pair, so that a difference potential is produced at a predetermined overload. The low-set relay LS controls the phase-comparison equipment, but the actual tripping of a circuit-breaker cannot occur until the high-set relay HS operates. The phase-comparison equipment is connected across the secondary of transformer SCT whereby carrier current may be applied to the line.
GB2820048A 1948-10-30 1948-10-30 Improvements in or relating to electrical protective arrangements Expired GB647050A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2820048A GB647050A (en) 1948-10-30 1948-10-30 Improvements in or relating to electrical protective arrangements

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2820048A GB647050A (en) 1948-10-30 1948-10-30 Improvements in or relating to electrical protective arrangements

Publications (1)

Publication Number Publication Date
GB647050A true GB647050A (en) 1950-12-06

Family

ID=10271883

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2820048A Expired GB647050A (en) 1948-10-30 1948-10-30 Improvements in or relating to electrical protective arrangements

Country Status (1)

Country Link
GB (1) GB647050A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6466663B1 (en) 1997-09-30 2002-10-15 Don Ravenscroft Monitoring system client for a call center

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6466663B1 (en) 1997-09-30 2002-10-15 Don Ravenscroft Monitoring system client for a call center

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