Figure 58. — Ladd's combination magneto- 

 electromagnet generator as used to drive an 

 arc light. From La Lumiere electrique, 1882, 

 vol. 7, p. 13, fig. 12. 



Figure 59. — Wheatstone's dynamo of 1866. 

 From J. Dredge, Electric Illumination, London, 

 n.d. (about 1882), vol. i, p. 137. 



is magnetically saturated and no further increase in 

 current is possible at that particular speed of armature 

 rotation. The distinctive term "dynamo-electric 

 machine," in contrast to the usual term "magneto- 

 electric machine," was applied to this new kind of 

 generator by Werner Siemens in his announcement 



Figure 60. — Varley's dynamo of 1866. From 

 J. Dredge, Electric Illumination, London, n.d. 

 (about 1882), vol. I, p. 138. 



Figure 61. — Siemens' dynamo of 1866. From 

 A. Thomalen, "Zur Geschichte der Dynamo- 

 Maschine," Beitrage zur Geschichte der Technik 

 und Industrie, 1916, vol. 7, p. 141. 



of the new principle. Since then, the term has 

 been shortened to "dynamo." 



Gramme was the first to make the dynamo a success 

 commercially.*^ He was a Belgian carpenter who 

 worked with a compatriot, Joseph van Malderen, at 

 the shop of the Societe I'Alliance as model-maker. 

 As Gramme's interest in electricity grew, he left the 

 shop to further his education and to become an 

 instrument-maker by working with Ruhmkorff and 

 then Disderi (or, some say, Froment). He finally 

 turned to working out his own ideas, and his first 



89 O. Colson, "Zenobe Gramme: Sa Vie et ses oeuvres," 

 Wallonia, 1903, vol. 11, pp. 261-279; Jean Pelseneer, <;CToAe 

 Gramme, Brussels, 1944, ed. 2. 



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