Dimensional Changes in Wires during Coiling Operations

摘要

When evaluating the properties of coils, either the magnetic field of an electromagnetic coil or the spring-constant of a coiled spring, it is common to assume that the wire's cross section remains the same as in its linear form. In reality, however, changes in this cross section become more pronounced as the ratio of the wire's thickness, H, (in the radial direction of the coil) to that of the coil's inner diameter, ID, approaches 0.05 and above. While these changes are functions of the above-mentioned ratio, they vary between the coil's ID and its outer diameter, OD. In designing coils for high current density, the ability to compute these changes becomes pertinent, mainly because it affects the minimum available clearance between the coil's loops. (fr)