Dynamic model of solenoids under impact excitation, including motion and body currents. II

For pt.I see ibid., p.142-8 (1988). Modeling of solenoids activated from a DC source (impact excitation) is difficult because of the coupling of a nonlinear magnetic system, which includes eddy currents, with a mechanical system that involves a time-varying airgap. The finite-element method (in two dimensions) has been successfully implemented to solve this complex problem. However, the large number of successive iterations involved makes it inconvenient when repeated design trials are made, for instance, during optimization. It is shown that the problem geometry, including eddy currents, can be satisfactorily approximated using only one dimension. The resulting set of equations is solved using the finite-difference method. Comparisons with test data and with 2-D finite-element calculations are conclusive.<>