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Featured researches published by Kazuaki Miyanaga.


IEICE Transactions on Electronics | 2007

Current and radiation noise up to GHz band generated by slowly breaking silver-compound contacts

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

A Study on Separation of Heat Generation and Heat Transfer Related to Temperature Rise of Silver Palladium Contact

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

Effect of the Thermal Constant on Temperature Rise of Silver Palladium Alloy Contacts

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

The Relationship between Voltage and Duration of Short-Time Arc Generated by Slowly Breaking Silver Contact

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

Effect of Heating Value on Contact Diameter at Low Speed Breaking Contact

Kazuaki Miyanaga; Yoshiki Kayano; Tasuku Takagi; Hiroshi Inoue


European Physical Journal-applied Physics | 2010

Current noise up to GHz band generated by slowly breaking silver-compound contacts with external dc magnetic field

Hiroshi Inoue; Hikaru Miura; Yoshiki Kayano; Kazuaki Miyanaga


IEICE Transactions on Electronics | 2011

Effect of Heat Conductivity on Bridge Break at Different Material Contact Pairs

Kazuaki Miyanaga; Yoshiki Kayano; Takashi Komakine; Hiroshi Inoue; Tasuku Takagi


IEICE Transactions on Electronics | 2013

Experimental Analysis of Arc Waveform Affected by Holder Temperature Change at Slowly Separation of Silver-Tin Dioxide Contacts

Yoshiki Kayano; Kazuaki Miyanaga; Hiroshi Inoue


IEICE Transactions on Electronics | 2010

Effect of Holder Heat Capacity on Bridge Shape at Low Speed Breaking Contact

Kazuaki Miyanaga; Yoshiki Kayano; Tasuku Takagi; Hiroshi Inoue


IEICE Transactions on Electronics | 2012

A Method for Suppressing Duration and Electromagnetic Noise of Contact Breaking Arc by Applying Pressure

Kazuaki Miyanaga; Yoshiki Kayano; Hiroshi Inoue

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