A CAD procedure of a cylindrical-faced electromagnet for typewriters

A computer aided design procedure is developed to design a cylindrical electromagnet used in typewriters. The main requirement is the maximum value of the kinetic energy stored in the plunger, under assigned supply conditions. The design procedure is split into three successive steps. Firstly an estimation of the core cross section is made, by maximizing a simplified function representing the convertible energy. Then a nonlinear finite element analysis is performed to define the pole geometry. Finally simulating the system behaviour, the converted energy is estimated together with the optimal initial position of the plunger. Experimental results are found to be in satisfactory agreement with the computed ones.