﻿58 Mr. H. Wilde on a Property of the Magneto -electric Current. 



mum effect of the combined current was obtained. It will there- 

 fore be evident that this property of the current, to maintain the 

 synchronism of the armatures, renders it unnecessary to employ 

 mechanical gearing of any kind for that purpose. 



Proceeding further in this investigation, 1 found that, in order 

 to produce synchronous rotation, it was not at all essential that 

 the circuit which conveyed the combined currents for producing 

 the light should be completed, provided that the ends of the 

 coils of each armature were connected respectively with the same 

 metal plates which formed the polar terminals of the machines. 

 In this case the armatures adjusted themselves to their normal 

 positions even more readily than when the current was produ- 

 cing the light. The accompanying diagram will assist in ex- 

 plaining these observations more fully. 



E 



-o I* 1 o 



G 



—4-^ H o- 



Let D and D represent the two armature-coils, which, though 

 each 280 feet long, may virtually be represented by a single 

 turn; E E the two outer extremities of the coils, both connected 

 by means of the metal rings and brushes with the metal termi- 

 nal plate F ; G Gr the inner extremities of the same coils, simi- 

 larly connected with the terminal plate H. The synchronous ro- 

 tation of the armatures and coils T> and D, as I have said, occurs 

 either when the light is produced by the combined, currents 

 transmitted from the polar terminals F and H, or when the cir- 

 cuit which conveyed these combined currents is broken. 



The synchronism, however, is no longer preserved when a 

 short circuit is made between the terminals F and H by substi- 

 tuting a good conductor for the carbon points, or for the long 

 piece of iron wire which was melted. Nor, again, was this syn- 

 chronism preserved when contact between the metal plate H and 

 one of the ends (G) of the coil was broken. In the latter case 

 it was observed that, whenever contact between G and H was 

 made and broken, a bright spark appeared at the point of dis- 

 junction so long as the rotation was not synchronous ; but when 

 the synchronism was reestablished, only a trifling residual spark 

 was visible. 



Although the synchronous rotation was preserved when the 

 terminals F H, from which the combined current was trans- 

 mitted, were disconnected from the electric lamp, yet it will be 

 seen, from an inspection of the diagram, that a complete metallic 

 circuit was in fact always formed between these terminals through 



