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It has been observed in our tests that the post arc current near the breaking limit of a CO<sub>2</sub> circuit breaker is 10 A or more, and the post arc current of a SF<sub>6</sub> circuit breaker is approximately 0.3 A. We explain this major difference in the post arc current with calculations using two serially-connected arc models. We prove that the arc(More)
[1] In order to investigate the characteristics of Pi 2 propagation observed in the highlatitude region, ground magnetometer data obtained at high-latitude CPMN stations were analyzed. The power of magnetic perturbation, (DH ) + (DD), were calculated for Pi 2 events observed at four stations from 11 February through 20 April 1996 and for Pi 2s observed at(More)
Multispacecraft data from the upstream solar wind, polar cusp, and inner magnetotail are used to show that the polar ionosphere responds within a few minutes to a southward IMF turning, whereas the inner tail signatures are visible within ten min from the southward turning. Comparison of two subsequent substorm onsets, one during southward and the other(More)
AE technology has been applied to gas leak detection and inspection. However, it is difficult to detect and inspect the gas leak consistently because measured AE waveforms are different from leak pressures and shapes of leak parts. In this report, first of all the effect of the pinhole diameter on AE characteristics during gas leak was investigated. The(More)
We present the first results of a data analysis method, developed by Sonnerup and Hasegawa (2011), for reconstructing three-dimensional (3-D), magnetohydrostatic structures from data taken as two closely spaced satellites traverse the structures. The method is applied to a magnetic flux transfer event (FTE), which was encountered on 27 June 2007 by at least(More)
A three-dimensional time-dependent computational magnetohydrodynamics (MHD) code has been developed for research and development of a rotary-type gas circuit breaker. A test computation of arc-plasma flows under externally applied magnetic field in a small chamber has been carried out by using the developed computational code. The computational results have(More)
The test to verify the making performance of high voltage switchgear is required and the standard also requires the making test. We have developed a large current making switch (rated voltage of 180 kV, trigger energy of 5.5 kJ) to mainly apply to making tests of high voltage switchgears, such as short-circuit making and out-of-phase. In this kind of test(More)
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