TWO-FREQUENCY APPROACH TO DETERMINE A TORCH DISCHARGE RESISTANCE WITHIN M.S. NEIMAN EQUIVALENT CIRCUIT WITH ADDED EQUIVALENT INDUCTANCE OF THE DISCHARGE

摘要

The practical value of the study presented is obvious due to the great potential of torch discharge (TD) for a variety of applications though being hindered by a substantial lag in its practice-oriented theoretical research. This paper considers a new approach suggested by the author to measure a TD resistance ( i R _( d ) ) with the discharge inductance i L being taken into account. The approach is backed-up with formulae enabling one to calculate i R _( d ) from the data measured at two frequencies, which are values of function i α , a voltage relation, at which the electrical and geometrical characteristics of the torch discharge remain unchanged. In particular, through this formula for i R _( d ) , an inequality was found allowing us to estimate the definition domain of i α . It is established that the frequency dependence of i α has its minimum at the resonance frequency of the discharge circuit i ω _( r ) , which becomes an asymptote at i L → 0 for a similar dependence of i α at i L ≡ 0. It is shown that in cases, when the effect of i L cannot be neglected, the minimum of function a is always located above the asymptote at the ordinate axis. A conclusion was made that the measured value of i α should correlate with the accuracy of the measuring equipment including devices that control the constancy of geometrical parameters of the torch discharge excited at two frequencies. Therefore, the measured value of a has to be as low as possible. It is feasible if the excitation frequencies are significantly spaced apart. The proposed approach provides a higher industrial resource efficiency.