High-Intensity Contact Opening Under 36-V DC Voltage Application for Mild Hybrid Vehicles

Abstract

This paper concerns the study of contact opening under dc voltage in the case of high-intensity current (a few hundred amperes). The application fields are mainly automotive and aeronautical systems. An experimental device has been designed in order to study the opening of contacts under various conditions. The influence of several parameters on contact opening is studied. These are the following: the opening velocity, the current intensity through the closed contact, the nature of the contact materials (Ag, Ag-12wt%SnO 2 ), the value of the inductance in the electrical circuit. The measured parameters characterizing the opening phase are as follows: the arc duration, the value of the electrode gap when the arc extinguishes, the arc energy, the maximal value of the contact voltage during the opening phase, and the electrode erosion. The study of the erosion is achieved with the help of a 3-D profilometer enabling the measurement of mass transfer and, for instance, of the amount of molten or evaporated metal.Index Terms-Electric arc, electrical contacts, erosion, hybrid vehicle, 36-V dc.

Stability, spatial extension and extinction of an electric arc in aeronautical conditions of pressure under 540 V DC

“…For other electrode materials several authors [14] observed that for I CC smaller than 40 A the arc duration was an increasing function of I CC . Besides, the constancy of the extinction distance has already been observed at atmospheric pressure for supply voltages of the order of 40 V DC [16] and was attributed to the appearance of instabilities of electromagnetic origin which destabilize the arc. -At high current value, the error bars are large because of instabilities which induce less reproducible measurement than at low current.…”

“…For every current values considered in this work, electric arc is even more unstable as the pressure is high and the mean stability length is in the range [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] cm. The influence of arc current intensity is more pronounced for pressure values below 6 Â 10 4 Pa.…”

“…Using these values to extrapolate the arc length for U sup = 540 V DC generates an important dispersion in d max value. For instance for I arc ≈ 30 A and P = 2.5 Â10 4 Pa d max will be in the range [11][12][13][14][15][16][17][18][19][20][21][22] cm and for I arc ≈ 100 A an estimation of d max is in the range [28-38] cm.…”