Influence of Voltage and Current on Arc Duration and Energy of DC Electromagnetic Contactor

In this paper, experimental results were described for a general DC electromagnetic contactor switching under a permanent magnet for arc extinguishing. The experiment circuit was a series circuit of source voltage E, resistive load R and DC electromagnetic contactor. The closed contact current Io was adjusted by R. The influence of E and Io on arc duration ta and arc energy Ea of break arc were experimented. The E had been changed within range of 50 -- 500V DC and Io was set from 5 to 30A at each voltage E. Arc voltage and current waveforms were measured with a digital oscilloscope. When E was high, arc duration ta became long. However, in 300V or more, ta shortens when Io is increased. In 200V, influence of Io on ta was not seen and arc duration became almost constant. In 50V, ta became long along with Io, it is clarified that permanent magnets doesn't influence for arc. However, shortening of the arc duration with permanent magnet was seen in 100V or more. We think that effect of Lorentz's force on the arc was different according to E and Io. In addition, when E and Io are high, it was found that arc energy Ea became large. Keywords -- DC electromagnetic contactor, arc discharge, arc duration, magnetic blast, arc energy, permanent magnet