Study on contact mechanism and electric resistance characteristics of twisted conductors

Abstract

AbstractThis paper analyzes the mechanical and electrical characteristics of the hand‐twisted conductor splices in communication cables. the validity of the analysis is verified by experiment. Concerning the mechanical characteristics, it is shown that in the physical contact of the conductors the central axis is twisted with an arbitrary pitch angle on a quasi‐cylinder with the radius equal to that of the conductor. Based on such representation of the contact mechanism, the contact pressure and contact width of the twisted conductors are calculated. Concerning the electrical characteristics, it is assumed that there is a similarity between the current distribution through the twisted conductor contact and the electric lines of force produced by the charge on the surface of contact. Based on such assumption, the constriction resistance of the twisted contact is calculated with consideration of the contact pressure and contact width. Estimation is also made on the growth process of the film resistance and the boundary film thickness due to the chemical substances formed on the conductors in contact. the electrical equivalent circuit for the twisted conductor contact is derived, including the constriction resistance, film resistance and conductor resistance. Using the derived equivalent circuit, an expression is derived for estimation of the contact resistance of the twisted conductors.