Inductive and Transformative Transducers with Short-Circuiting Ring

An ideal short-circuiting ring (R = 0) represents an infinite magnetic resistance for magnetic flux. A core of suitable shape allows an influence to be exercised upon the path of magnetic flux in a ferromagnetic circuit by displacing a short-circuiting ring. This fact may be utilized to construct transformative or inductive transducers. Two practical arrangements are described, and the effects on the characteristics of various parameters such as short-circuit resistance, core geometry, frequency of the energizing current, etc., are explained. The transducers examined attain a linearity error of 0.3 percent for displacement of 10 cm. The transducers, as described, do not show any wear, and the force of the short-circuiting ring exerted on the object of measurement remains a factor of 1000 below the force of the transducer used previously. Consequently, transducers (for linear travel or angular rotation) with short-circuiting rings are suitable both for use as rugged shop instruments and for precision transducers in metrology and control.