The up-and-down method can determine the flashover voltage of
a material such as air, which i.s self-restoring. The step-up
method is a technique to determine the impulse dielectric breakdown
voltage Y of an insulator which is not reusable after breakdown.
The up-and-down method, assuming the breakdown voltage is subjected
to the normal distribution, obtains the estimates and their errors
ofthe mean and the standard deviation. The conventional step-up
method has no standard procedure for obtaining them. On the assumption
that Y follows a normal distribution, this paper describes: (1)
a procedure for obtaining the estimates and their errors of the
mean b and the standard deviation ct by the maximum likolihood
estimation, and (2) a study of the optimum value for the minimum
required number N of specimens, the voltage difference d betwee'n
two consecutive steps, and the mln number m of repeat tests at
each voltage step. or an efficient test to obtain reliable estimates,
it is desirable thatNmin = 20, d = 0.6 - 1.2 times (~;, and rr~
= 1. 'l'his technique may be applicable to mechanical failure
tests and biological pharmaceutical tests by replacing the ter'm
'impLrlse dielectric breakdown' with 'impact failure' and 'death',
respectively.
The paper written in English is available
upon request.