I
think I found out Whodunnit.
While Tesla came close with this patent, granted Oct 22 1889, [ refer specifically to Fig 5. ]
http://project-ufo.com/tesla/00413353.pdfI am confident the honor must go to Charles S Bradley of Yonkers, Westchester County, NY., another disaffected ex Edison employee who struck out on his own.
US Patent # 409450
Filed Oct 20 1888. Granted August 20 1889
http://www.google.com/patents?id=nu9gAAAAEBAJ&pg=PP1&dq=1888+Charles+Bradley#PPP2,M1
A full rotary converter scheme, all on one armature, ac supply, dc delivery.
Bradley issued a raft of patents at this time for polyphase motors and related electrical devices.
He sold his company to GEC in 1897, who by now were committed to ac generation and transmission. [Edison seems to have taken a ‘back seat’ at GEC after Niagara.]
Westinghouse Electric are recorded as frantically working on both the Columbia Expo and research into polyphase motors and a rotary converter in 1892, after ceasing research in 1890 due to funds shortages. These devices were both essential to their Niagara proposal, since they had to provide dc supplies for Buffalo as well as effective ac industrial motors if they were to succeed against Edison’s dc bid.
Alan
