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A Comparison of Arc Characteristics in Switching in Vacuum and in Oil


Harness, George Thomas, Jr. (1933) A Comparison of Arc Characteristics in Switching in Vacuum and in Oil. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/29CA-HX70.


This thesis describes the results of an investigation of the arc end glow discharges occurring between the contacts when an alternating current is interrupted by an oil circuit breaker; and a comparison with similar phenomena in the vacuum circuit breaker is made. This investigation was made by taking cathode-ray oscillograms of the variation of voltage across the contacts, and the current through the discharge, with time, and the variation of the voltage across the contacts with the current through the discharge. Circuit voltages of 15,000 and 2300 were used, and currents up to 45 amperes were interrupted.

The discharges across the separating contacts of an oil circuit breaker are discussed in detail, and an analysis of the variations near the zero of the current wave is made. This investigation shows that for a brief period, of the order of 300 microseconds, at the end of each half cycle of the current wave the current between the contacts is of a very small magnitude, and may be considered essentially zero. During this interval the voltage completes a part of an oscillation, the frequency of which is apparently determined by the constants of the connected circuit, and rises in the reverse direction until a certain maximum is reached. After this value is reached current again flows end the usual glow and arc phenomena are observed.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Mechanical Engineering
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Mechanical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Unknown, Unknown
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1933
Record Number:CaltechTHESIS:02282017-092613459
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10072
Deposited By: Benjamin Perez
Deposited On:01 Mar 2017 15:50
Last Modified:16 Aug 2023 23:07

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