CHAPTER IV SMALL POWER MOTORS
In order for a motor to develop any appreciable amount of power it must be much larger than any of those which have been described in these pages so far, and must be constructed in a most painstaking manner. It will be necessary to use a great deal more iron in the field and armature and also to make the space between them as small as possible. A motor having a small separation between the field poles and the armature will develop more power than one having a greater separation.
FIG. 59.—A Vertical Battery Power Motor.
The most efficient types of small power motors have laminated field and armature frames, that is, they are built up of a large number of thin metal punchings. The amateur experimenter who has limited facilities for carrying out his work would find it difficult to make parts of this sort to good advantage and so the motors described here have been designed with cast iron armatures and field frames.
Those who wish to secure a set of castings from their own patterns can possibly save part of the expense if they do not consider the extra labor of first making the patterns.
Two types of motors are described, one vertical and the other horizontal. Both are intended to operate on a battery current of 3-6 volts and if carefully built will deliver a surprising amount of power.
FIG. 60.—Details of the Field Frame of the Vertical Motor.