Experimental study of the voltage recovery characteristics of small air gaps

The electrical recovery characteristics of relatively small air gaps between 0.3 and 9 mm were determined using a two-pulse method. The first pulse was used to over-volt the gap and initiate the arc current. The second pulse was used to determine the recovery voltage of the gap. A plot of the recovery voltage with time was obtained by varying the time delay of the second pulse relative to the arc extinction time of the first arc, in the time range form 50 μs to 100 ms. It is found that the recovery characteristics are independent of the electrode materials (Cu, Al , St) and the arc current in the range from 40 to 200 A. It is also found that the shorter gaps and the rod plane gaps recover their dielectric strength faster than the longer gaps and the sphere gaps, respectively