SCIENCE— ADVERTISEMENTS 



Complete Dynamo Electric Machinery Apparatus 



For Demonstrating 



Direct Current Motors and Generators 

 Alternating Current Rotating Field and Induc- 

 tion Motor 

 The Rotary Converter 



The Synchronous Motor 

 The Alternating Current Generator 

 The Transformer and Its Principles 

 Two or Three Phase Alternating Current Phe- 

 nomena 



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This apparatus consists essentially of two fields which may be fitted with poles on which are wound coils and 

 these fields may have 2, 4, or 6 poles for direct current work or 3 or 6 poles for three phase alternating current work 



A simple direct current armature is supplied for mounting in this field and with this armature may be demon- 

 strated a series or shunt wound motor or dynamo and all characteristics of direct current dynamo electric machinery 

 of either 2, 4, or 6 poles. This furnishes much valuable information regarding the connections of the different poles, 

 the direction of rotation, etc. 



The aluminum cup for use in this magnetic field illustrates the principles of the closed circuit rotor for induction 

 motors. The reversal of one of the field coils shows reversal of direction of rotation and other similar important 

 principles may be shown. 



The converter may be demonstrated by placing the armature which has slip rings on one side in the field shown 

 on the right and arranging the poles and connecting a battery so as to run it as a direct current motor. The brushes 

 underneath will collect alternating current and this may be used for ringing bells and may be shown to be alternating 

 by the use of meters. 



The Synchronous motor may be shown by carefully increasing the frequency of the alternating current generated 

 by increasing the speed of the central handle and at the same time have the armature connected to this alternating 

 "rrent and 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 

 1 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 current, a rotating field may be produced, and by the use of the mounted magnetic 

 needle it may be shown how this needle is whirled around as the field rotates. 



This set contains a minimum of parts but enables teaching of practically every application of either alternating 

 or direct current, dynamo-electric power apparatus. 



This outfit is complete with the two fields and the A. C. Generator mounted on a base and the following parts: 

 6 field coils, i direct current armature, i direct current armature with slip rings, i mounted magnetic needle, 1 aluminum 

 cup rotor, i transformer yoke with both primary and secondary coils. 



cA Sign of ^ality ^^^ffiSjJ c^ Mark of Service 

 W. M. WELCH SCIENTinC COMPANY 



Manufacturers, Importers and Exporters of 

 Scientific Apparatus and School Supplies 



1516 Orleans Street 



CHICAGO, ILL., U.S.A. 



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