SCIENCE— ADVERTISEMENTS 



Complete Dynamo Electric Machinery Apparatus 



For Demonstrating 



Direct Current Motors and Generators 

 Alternating Current Rotating Field and 



Induction Motor 

 The Rotary Converter 



The Synchronous Motor 



The Alternating Current Generator 



The Transformer and Its Principles 



Two or Three Phase Alternating Current 



Ph 



enomena 



alternating 



rk. 



sentially of two fields which may be fitted 

 ; 2, 4, or 6 poles for direct current work o 



ith poles on which are wound 

 3 or 6 poles for three phase 



A simple direct current armature is supplied for mounting 

 demonstrated a series or shunt wound motor or dynamo and ; 

 electric machinery of either 2, 4, or 6 poles. This furnishes nn 

 nections of the different poles, the direction of rotation, etc. 



n this field and with this armature may be 

 11 characteristics of direct current dynamo 

 ich valuable informaton regarding the con- 



for 



The aluminum cup for use 

 nduction motors. The rever 

 r similar important principle 



In this 

 ;al of 



ignetic field illustrates 1 

 of the field coils sho\\ 

 shown. 



The converter may bi 

 field shown on the right : 

 current motor. The brush 

 bells and may be shi 



ngs on one side 



trated by placing the armature which has slip 



iging the poles and connecting a battery so as to run it as a direct 

 11 collect alternating current and this may be used for ringing 

 meters. 



The Synchro! 

 rent generated by 

 connected to th" 



to be alternating by the use 

 motor may be shown by 



alte 



the 



atmg 



fully increasing the frequency of the alternating cur- 

 speed of the central handle and at the same time have the armature 

 d the field coils in the proper order connected to direct current. 



The alternating current generator may be demonstrated by energizing the fields by direct current 

 and using the armature that has the slip rings on it. 



One of these fields has two slots in it for holding a yoke on which are two concentric, removable 

 coils and with this may be shown all the principles of the transformer, as transformation ratio, etc. 



When used for alternating current work, that part of the apparatus which is mounted on the center 

 of the base converts direct current into alternating current and there can be obtained either single phase, 

 two phase or three phase current. 



By the use of the polyphase cu 

 mounted magnetic needle it may be sho 



mt, 

 how thi: 



minimum of parts but enables teaching practically every application of either 

 lit, dynamo-electric power apparatus. 



nplete with the two fields and the A. C. Generator moun 

 Is, 1 direct current armature, 1 direct current artnatur 

 minum cup rotor, 1 transformer yoke with both primary 



[ on a base and the follow- 

 with slip rings, 1 mounted 

 nd secondary coils. 



A SIGN OF QUALITY 



AL1TY_ 



A MARK OF SERVICE 



W. M. WELCH SCIENTIFIC COMPANY 



Manufachjrers, Importers and Exporters of 

 Scientific Apparatus and School Supplies 



1516, Orleans Street CHICAGO, ILL., U. S. A. 



