Kazuaki Miyanaga
Akita University
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Featured researches published by Kazuaki Miyanaga.
IEICE Transactions on Electronics | 2007
Yoshiki Kayano; Tatsuya Nakamura; Kazuaki Miyanaga; Hiroshi Inoue
To clarify the mechanism of the generation of electromagnetic (EM) noise, current and radiation noise up to the GHz band generated by slowly breaking silver-compound contacts were investigated experimentally. The current and radiation noise at the GHz band were observed. It was demonstrated that the frequency spectrums of the current and radiation noise correspond to the frequency responses of the circuit admittance and radiation efficiency of the experimental setup, respectively. It was revealed that even if current noise at the GHz band is very small, it can cause a large EM radiation noise because of the high radiation efficiency. From the time-frequency domain characteristics of current noise, it was clarified that the peaks of current noise at 10 MHz band arise immediately after the initiation of the arc discharge and the transition from metallic phase to gaseous phase. On the other hand, the peak current noise above 100 MHz arises immediately after the initiation of the arc discharge.
IEICE Transactions on Electronics | 2006
Kazuaki Miyanaga; Yoshiki Kayano; Hiroshi Inoue
In this paper, the separation of heat generation and heat transfer related to temperature rise of silver palladium contact was investigated experimentally in order to predict the temperature rise of contact by the use conditions such as voltage range between 25 to 40 V, current range between 3.2 to 5.0 A and silver palladium alloy (AgPd) materials. Firstly, relationship between temperature rise of contact and supply power was discussed. The effects of heat generation and heat transfer on temperature rise were separated and quantified by least squares method. Secondly, effects of durations and integral powers of bridge and arc on temperature rise were also discussed by changing supply power. Results show that the integral power of the bridge increases when supply power increases. As the supply power increases, integral power of arc also increases. The temperature rise is dominated by integral power of bridge. Remarkable difference of bridge duration can not be seen in the five materials (AgPd 30 , AgPd4o, AgPd 50 , AgPd 70 and Pd). The supply power is increased, arc duration gets longer. As weight percent of Pd content increases, the effect of supply power on arc duration becomes larger. Consequently, the integral power of arc increases. This study is a basic consideration to realize methods predicting temperature rise of contact.
IEICE Transactions on Electronics | 2007
Kazuaki Miyanaga; Yoshiki Kayano; Hiroshi Inoue
In this paper, a method of separating the effects of the thermal diffusivity, durations and integral powers of the bridge and arc on the temperature rise of AgPd contacts was proposed. First, the effects of the Pd content on the durations and integral powers of the bridge and arc, and the temperature rise of the contacts were discussed. Because the integral power of bridge was larger than that of the arc under our experimental conditions of 40 V open-circuit, 5 A close-circuit and 100 μm/s opening velocity, the temperature rise of the contacts was dominated by the bridge. No remarked difference in bridge duration can be seen among the six materials. Although the integral power of the bridge in the case of Pd was maximum, the maximum temperature rise of the contact was observed in the case of AgPd 60 . To clarify the contribution of each factor, the effect of thermal diffusivity on the temperature rise of the contact was evaluated by the finite-difference time-domain (FDTD) method. In the case of Pd, because its thermal diffusivity was largest, heat diffused rapidly. On the other hand, the thermal diffusivity in the case of AgPd 60 was small, and heat diffused slowly to the holders. The maximum temperature rise was observed in the case of AgPd 60 . It was demonstrated that the proposed method of separating the effects of thermal diffusivity, durations and integral powers of the bridge and arc on the temperature rise of contacts is effective in enabling us to understand contact phenomena.
IEICE Transactions on Electronics | 2008
Yoshiki Kayano; Hikaru Miura; Kazuaki Miyanaga; Hiroshi Inoue
Arc discharge generated by breaking electrical contact is considered as a main source of an undesired electromagnetic (EM) noise. To clarify mechanism of generation of the EM noise, feature extraction of bridge and short-time arc waveforms generated by slowly breaking Ag contact was discussed experimentally. The short-duration time arc before the ignition of the continuous metallic arc discharge was observed. The highest probability density voltage is defined as short-arc sustainable voltage (SASV). The relationship between SASV and duration of short-time arc was quantified experimentally. It is revealed that as the arc voltage of the short-time arc is higher, its duration becomes longer.
IEICE Transactions on Electronics | 2009
Kazuaki Miyanaga; Yoshiki Kayano; Tasuku Takagi; Hiroshi Inoue
European Physical Journal-applied Physics | 2010
Hiroshi Inoue; Hikaru Miura; Yoshiki Kayano; Kazuaki Miyanaga
IEICE Transactions on Electronics | 2011
Kazuaki Miyanaga; Yoshiki Kayano; Takashi Komakine; Hiroshi Inoue; Tasuku Takagi
IEICE Transactions on Electronics | 2013
Yoshiki Kayano; Kazuaki Miyanaga; Hiroshi Inoue
IEICE Transactions on Electronics | 2010
Kazuaki Miyanaga; Yoshiki Kayano; Tasuku Takagi; Hiroshi Inoue
IEICE Transactions on Electronics | 2012
Kazuaki Miyanaga; Yoshiki Kayano; Hiroshi Inoue