Effect of voltage type and polarity on the gas temperature of an arc over an ice surface

The rotational temperatures of arcs propagating over an ice surface, under DC-positive, DC-negative and AC applied voltages, have been measured and compared. The spectra of the emitted light during the arc propagation were collected and analyzed using a spectroscopic system. A strong diatomic molecular band of OH was observed from the captured spectra with two distinct peaks at about 307 nm and 309 nm. The rotational temperature was derived from the relative intensities of two groups of rotational lines corresponding to the peaks of the OH (A-X) (0, 0) vibrational band. From the comparison of arc temperatures under different applied voltages, it was found that the DC-positive arc is hotter than the DC-negative one. The arc temperature under AC applied voltage was found to be close to that of DC-negative voltage.