The spatial distributions of spectral intensity and temperature in the cross section of an arc column between separating Pd contacts

The authors have measured the distributions of spectral intensities of PdI-447 nm and PdI-540 nm and the distribution of the temperature in the cross section of a Pd arc column near the cathode contact between separating Pd contacts in circuits of DC 50 V/3.3-5.0 A, As a result, the distributions of spectral intensities in the cross section of an arc column were not symmetrical from ignition to extinguishing of a breaking arc, and the cross-sectional area of an arc column became large past the middle of a breaking arc. The total amounts of measured spectral intensities decreased slightly in case of long arc or remained constant in the case of short arc past the middle of a breaking arc. The peak value of the distributions of spectral intensities in the cross section of an arc column was strong at the beginning of the breaking arc and became weaker with development of the breaking arc. These intensities were greater in the case of a long arc than in the case of a short arc. The radial distributions of temperature in the cross section of the arc column were constant. The temperature in the position of the peak value of spectral intensity in the cross section of the arc column rose at the beginning of a breaking arc and remained constant at about 6000 K. Judging from the time dependence of spectral intensities and arc temperatures near the cathode contact, the arc duration was long when metal-vapor quantity was large and metal-vapor density was high between contacts at the beginning of a breaking arc.