Ans. It usually forms the frame of the dynamo as shown in figs. 205 and 206.
Ques. What may be said of the cores?
Ans. The cores, which are usually of circular form, carry the coils of insulated wire used to excite the magnets.
Classes of Field Magnet.—Although numerous forms of field magnet have been devised, they can be classed into two groups according to the type of pole, as:
1. Salient pole; 2. Consequent pole.
The distinction between these two types of pole is shown in figs. 201 to 203. By inspection of the figures, it will be seen that the term salient applies to poles produced when the pole pieces form the ends of the magnet, as distinguished from consequent poles, or those formed by coils wound on a continuous metal ring or equivalent.
In the salient pole bipolar magnet, the winding may be either upon the limbs, M M fig. 202, or upon the yoke, Y as shown in fig. 201. The magnetic circuit of salient and consequent poles is indicated in the figures by the dotted lines.
