The Design of Powerful Electromagnets Part II. The Magnetizing Coil

In Part I of this article it is shown that the efficient use of iron in electromagnets is dependent on the design of efficient magnetizing coils. The characteristics of such magnetizing coils are discussed, and it is shown that the important factors are the shape of the coil, the power available, the distribution of current density, and the efficiency of cooling. Formulae applicable to coils of various types are derived, and the main features of an efficient design are determined.