Journal ArticleDOI
Air-Break Magnetic Blow-Outs For Contactors and Circuit Breakers Both A-C. and D-C
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TLDR
In this article, a blowout coil is connected in series with each pair of current-rupturing contacts, in order to avoid the possibility of gasification and explosion on heavy short circuits.Abstract:
Magnetic blow-outs have been used in contactors, circuit breakers and controllers for many years for rupturing both a-c. and d-c. power circuits, but their commercial use, particularly on alternating current has been largely confined to relatively low voltages. Oil circuit breakers and switches have been generally used for rupturing high-voltage a-c. power circuits, and their development has reached a high state of perfection. The air break has the advantage of avoiding the possibilities which attend the use of any inflammable material?like oil, with its possible gasification and explosion on heavy short circuits. While there are many different types of magnetic blow-outs this paper deals largely with the ``individual'' type, in which a blow-out coil is connected in series with each pair of current-rupturing contacts, since it is with this type that most of the progress and studies have been made in recent years. Contactors and circuit breakers with the ``individual'' type of blow-out are now used almost exclusively in the main d-c. power circuits of the 1500 and 3000-volt d-c. railway systems. Oil circuit breakers have been tried for this service, but they are rather unsatisfactory because there is no periodic zero point in the current wave at which the oil can form an insulating seal between contacts. The oil under d-c. arc conditions carbonizes rapidly and involves the possible danger from explosive gases. Recently the use of magnetic blow-out contactors on a-c. circuits has been extended to moderately high voltage and capacity. Short-circuit tests on a 6600-volt, 26,700-kv-a.read more
Citations
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Journal ArticleDOI
Extinction of a Long A-C. Arc
TL;DR: In this paper, the authors analyzed the extinction of an a-c. arc as depending on two factors, the rate of recovery of dielectric strength of the arc space after current zero, and the rate at which voltage tending to reignite the arc is applied by the external circuit.
Proceedings ArticleDOI
Fundamental characteristics of arc extinction by magnetic blow-out at DC voltages (<500V) II
TL;DR: In this paper, a model switch with three levels of magnetic blow-out and gap width and arc length at arc extinction were obtained by a high-speed camera in range of current less than 5 A and voltage lower than 500V.
Journal ArticleDOI
Observations on the Development of Arc Interrupters of Small Pysical Volume for Industrial Circuit Breakers with Large Interrupting Ratings
TL;DR: In this article, an interrupter was developed for a 50-ka (kiloamperes) 600-volt industrial circuit breaker, capable of being mounted, four-high, in a switchboard with a height of 90 in.
Journal ArticleDOI
The Development, Design, and Performance of Magnetic-Type Power Circuit Breakers
L. J. Linde,B. W. Wyman +1 more
TL;DR: In this paper, the treatment of the arc in this breaker to obtain a high are resistance is explained in some detail, and design practices and operating characteristics of the final magnetic type breaker are reviewed.
Journal ArticleDOI
Performance Criteria of D-C Interrupters
E. W. Boehne,M. J. Jang +1 more
TL;DR: In this article, a new approach to the analysis of the performance of d-c interrupters has been made in which the arc voltage of the interrupter is considered on an equal footing with the generated voltage, and the effect of variations in the circuit constants as well as circuit breaker speed and arc voltage wave shape and magnitude are evaluated on a quantitative basis.