WHAT MAKES THE TROLLEY CAR GO. 



327 



17. — Armature of Electuic Railway Motor. 



top by means of hinges, g g, Fig. 15, and also by a number of bolts, 

 which are not so clearly shown. The gear wheels are also located 

 within a casing, which (Fig. 16) is made so as to be readily opened 

 whenever it becomes necessary. All the vital parts of the ma- 

 chine are entirely covered, and are not easily injured by mud or 

 water. 



The construction of the armature and commutator is well illus- 

 trated 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 sur- 

 face of the armature 

 core, but, from Fig. 

 17, it will be noticed 

 that they are located 

 in grooves. A rail- 

 way 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. 



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 ex- 

 posed it can not be injured, no matter how much mud may accumu- 

 late 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 there- 

 by. Another reason is that an electric motor can, if called upon, 

 develop an amount of power two or three times greater than its 



