The construction of the armature and commutator is well illustrated in [Fig. 17], which shows this part of the machine by itself. The armature is marked A, the shaft B, and the commutator C. In the diagrams, [Figs. 9, 10], [11, and 12], the wire coils are represented as wound upon the surface of the armature core, but, from [Fig. 17], it will be noticed that they are located in grooves. A railway motor armature core, when seen without the wire coils, looks very much like a wide-faced cog wheel with extra long teeth, not very well shaped for gear teeth. In [Fig. 17] the ends of the teeth are marked D, and the grooves within which the wire is wound are marked E. The coils are not wound so that their sides are on diametrically opposite sides of the armature core, but so that they may be one quarter of the circumference apart, and, as will be noticed, the wires are arranged so as to fit neatly into each other at the ends of the armature core. The bands marked F F F F are provided for the purpose of holding the wire coils within the grooves. The flanges H and I are simply shields to prevent oil, grease, or even water, if it should pass through the bearings, from being thrown upon the commutator or armature. The pinion through which the armature imparts motion to the car-wheel axle is not shown in [Fig. 17], but it is mounted upon the taper end of the shaft.
Fig. 17.—Armature of Electric Railway Motor.
An electric railway motor is a machine that is characterized by extreme simplicity (there being only one moving part), compactness, and great strength. In addition, as none of the working parts is exposed it can not be injured, no matter how much mud may accumulate upon it. One of the reasons why the electric railway motor has met with such unparalleled success is that it is a machine that can withstand the roughest kind of usage without being damaged thereby. Another reason is that an electric motor can, if called upon, develop an amount of power two or three times greater than its full-rated capacity without injury, providing the strain is not maintained too long. A steam engine or any other type of motor that has ever been used for railway propulsion if loaded beyond its capacity will come to a standstill—that is, it will be stalled—but an electric motor can not be stalled with any strain that is likely to be placed upon it. If the load is increased the motor will run slower and the current will become greater, thus increasing the pull, but the armature will continue to rotate until the current becomes so great as to burn out the insulation. A railway motor calculated to work up to twenty-five-horse power will have to develop on an average about six-or seven-horse power, but if the car runs off the track on a steep grade, and has such a heavy load that the motor is called upon to develop one-hundred-horse power for a few seconds, the machine will be equal to the occasion. This result a steam, gas, or any other type of engine can not accomplish, and it is this fact as much as anything else that has given the electric motor the control of the street-railway field.
[To be continued.]
WOMAN’S STRUGGLE FOR LIBERTY IN GERMANY.
By MARY MILLS PATRICK, Ph. D.,
PRESIDENT OF THE AMERICAN COLLEGE FOR GIRLS AT CONSTANTINOPLE.
It is during the latter part of the present century that a general movement has arisen to give women their rights in business life and in political and social affairs. It is the intention of this article to treat of this movement, especially in its relation to education, in Germany, where, of all civilized lands, it has had apparently the smallest results. Progress in the direction indicated has been, however, far greater than appears on the surface, and the movement is slowly taking shape in a form that will gain official recognition and support, and the way is being prepared for scholarly attainments among the women of Germany, superior, possibly, to those of the women of other nations.
There is, moreover, an ideal side to this movement in Germany not altogether found in other lands. The motive for advanced study is more largely joy in the study itself, and desire to supply the spiritual needs of an idle life. In order to understand this ideal tendency it is necessary to cast a glance backward over nearly three hundred years.
Let us begin with the contest which was waged so successfully for the development and protection of the German language, first against the Latin and later against the French. In this struggle women took a prominent part, especially through membership in the society called the “Order of the Palms,” which, before the beginning of the Thirty Years’ War, united the strongest spirits of Germany for this purpose. The first woman to join this society was Sophie Elizabeth, Princess of Mecklenburg, married in 1636 to the Herzog of Braunschweig. She was followed by many others, both of the nobility and the common people, and was named by virtue of this leadership “The Deliverer.”