ABSTRACT
This chapter describes the basic principles of electromagnets and shows how to calculate the performance of several different magnets. It also shows that how to calculate the properties of direct current (DC) magnets, including force, inductivity, reluctance, ampere-turns, and flux. The chapter compares to DC magnets the properties of several alternating current (AC) magnets and discusses the energy losses due to hysteresis, iron core, eddy currents, and rivets. It also describes several shading coils which are used to reduce vibration in AC magnets and explains the effect of the shading coil on magnetic flux and force calculations. The chapter also discusses some other techniques for reducing vibrations in AC magnets. Several types of magnets have more than one yoke-to-armature surface. However, in many of these magnets, there is only one air gap in the direction of the stroke.
