Parameter Study on the Electrical Contact Resistance of Axially Canted Coil Springs for High-current Systems

This parameter study investigates the influence of several design parameters (wire diameter, canted angle, coil height, spring diameter, number of turns) and amperage on the contact force and electrical resistance of axially canted coil springs. The correlations are quantified by a full factorial experiment that is based on a numerical finite element model. The static load deflection curve of the spring is experimentally verified by a compression load cell, which links contact forces to their corresponding spring deflections. Varying amperage and deflection are applied through a test setup with Four-terminal sensing to measure the total contact resistance. An analytical model is developed to separate the bulk and constriction resistances of spring and mating partner from the total contact resistance. The results allow the identification of an optimal spring configuration particularly for high-current contacts.