Abstract: A number of indeterminate factors influencing the true distribution of electric current flowing through the Betzs ring specimen were enumerated. The difficulty to model Betz ring at present was introduced. The simplest hypothesis, where the electric current uniformly distributes in the Betzs ring specimen as an approximation of zero degree, was postulated. It is deduced that the geometrical dimensions of the Betzs ring had to satisfy certain relationship. Checking computations indicated that the design of the Betzs ring specimen was rational.