Temperature and metal vapor near the cathode in copper breaking arcs according to spectroscopic measurement

The spatial distribution of the intensities of two spectra are measured using the optical filtering spectroscopic method for breaking arcs in air between copper electrodes interrupting circuits of dc 50 V and 2.5 to 5.0 A, and the temperature and the metal-vapor quantity in the cross section of the arc column near the cathode are calculated from these intensities. Results show the distribution of spectral intensities in the cross section of the arc column is nearly symmetrical from the ignition to the extinction of the breaking arc. The total measured spectral intensities and the peak values of spectral intensities in the cross section of the arc column increase at the beginning and thereafter decrease gradually with the development of the breaking arc. At the fluctuation of the arc voltage wave, which occurs in a copper breaking arc, the total values of the measured spectral intensity and the peak intensity increase rapidly and the metal-vapor quantity also increases by a large amount, but change in temperature is slight.