GB857014A - Improvements in or relating to time delay circuits embodying transistors - Google Patents

Improvements in or relating to time delay circuits embodying transistors

Info

Publication number
GB857014A
GB857014A GB2828158A GB2828158A GB857014A GB 857014 A GB857014 A GB 857014A GB 2828158 A GB2828158 A GB 2828158A GB 2828158 A GB2828158 A GB 2828158A GB 857014 A GB857014 A GB 857014A
Authority
GB
United Kingdom
Prior art keywords
voltage
capacitor
diode
relay
resistor
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
GB2828158A
Inventor
Niles Fraser Schuh Jr
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.)
CBS Corp
Original Assignee
Westinghouse Electric Corp
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 Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to GB2828158A priority Critical patent/GB857014A/en
Publication of GB857014A publication Critical patent/GB857014A/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
    • H02H3/02—Details
    • H02H3/027—Details with automatic disconnection after a predetermined time
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/28—Modifications for introducing a time delay before switching

Landscapes

  • Emergency Protection Circuit Devices (AREA)

Abstract

857,014. Protective cut-out arrangements. WESTINGHOUSE ELECTRIC CORPORATION. Sept. 3, 1958, No. 28281/58. Class 38 (5). [Also in Group XL (c)] A protective circuit comprises a time delay network in which a capacitor charges through a resistor when a voltage exceeds a predetermined value, the capacitor voltage being used to control the current through a transistor and a rectifier being arranged in a discharge circuit for the capacitor to render the discharge circuit inoperative while the capacitor is charging. If the voltage from a three-phase rectifier network 21 exceeds a predetermined value a Zener diode 27 conducts and a capacitor 25 accordingly commences to charge through resistors 23 and 26. The charging continues until the voltage across the capacitor has reached a value such that a Zener diode 31 conducts and causes a transistor 32 to conduct. This causes a further transistor 33 to draw a current from an H.T. supply source 37 so operating the protective relay 35. The time delay provided by the circuit depends upon the value of the adjustable charging resistor 26 and also upon the amount by which the input voltage exceeds the breakdown voltage of the diode 27, so that short duration high voltages do not operate the relay. When the input voltage drops below the breakdown voltage of diode 27 the capacitor discharges rapidly through a diode 29 which then becomes conductive. It is stated that the relay could be replaced by a static bi-stable circuit and that resistor 26 may be replaced by a non- linear resistor such as a selenium rectifier to obtain a desired time voltage characteristic. The voltage at which charging commences could be determined by a relay instead of by Zener diode 27.
GB2828158A 1958-09-03 1958-09-03 Improvements in or relating to time delay circuits embodying transistors Expired GB857014A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2828158A GB857014A (en) 1958-09-03 1958-09-03 Improvements in or relating to time delay circuits embodying transistors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2828158A GB857014A (en) 1958-09-03 1958-09-03 Improvements in or relating to time delay circuits embodying transistors

Publications (1)

Publication Number Publication Date
GB857014A true GB857014A (en) 1960-12-29

Family

ID=10273166

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2828158A Expired GB857014A (en) 1958-09-03 1958-09-03 Improvements in or relating to time delay circuits embodying transistors

Country Status (1)

Country Link
GB (1) GB857014A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2237155A (en) * 1989-10-18 1991-04-24 Plessey Co Plc Electrical monitoring circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2237155A (en) * 1989-10-18 1991-04-24 Plessey Co Plc Electrical monitoring circuit
GB2237155B (en) * 1989-10-18 1993-08-04 Plessey Co Plc Improvements relating to monitoring circuit arrangements

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