Lumped modeling of rotary transformers, heads and electronics for helical-scan recording

In this paper lumped network models of rotary transformers are presented, as used in helical-scan recording. The adopted modeling techniques are based on a hybrid (partly electrical, partly magnetic) network approach in which the permeability of magnetic parts is modeled using a relaxation description. To describe the magnetic parts use is made of the permeance-capacitance analogy. Finite element calculation results are presented to indicate the main flux and stray flux paths in a rotary transformer. Based on these results accurate lumped network models are constructed using building blocks like corners, T-parts, half-annuli, etc. Some non-trivial building blocks are described in more detail. The transformer models are characterized by geometrical and material parameters. As an example the modeling concept is applied to a two-channel coaxial rotary transformer. Some simulation results and comparisons with measurements on a practical system are discussed.<>