Armature of Direct-Current Generator

Author: E.E. Kimberly

In direct-current generators, the conductors are laid in slots on the periphery of a laminated soft-steel cylinder called the armature core. Fig. 10-1 shows the rudimentary magnetic field and the armature elements, and Fig. 10-2 shows an armature.

Fig, 10-1. Rudimentary Field and Armature Elements

In all generators or those designed for Elements low voltage, each slot holds many conductors wound in long narrow coils. For simplicity, all coil sides in wiring diagrams will be shown as single conductors. See the elemental coils on the armatures of Figs. 10-6 and 10-8.

In modern generators, all conductors are not located on the same circle as in Fig. 9-1 (a), but the conductors are equally divided between two concentric circles, forming a double-layer winding as in Fig. 10-1. Inasmuch as the emf generated in a conductor of a direct-current generator need not be sinusoidal, the surfaces of the poles are made to conform almost to the circular contour of the armature, in order that the magnetic circuit may be more easily magnetized.