March 25th, 1890
George W. Clapp, Esq.,
No. 373 Atlantic Avenue
Boston, Massachusetts
Dear Sir:-
In reply to the question proposed in your letter under date of 12th instant, addressed to Mr. Edison, would say:- At the moment of removing the battery, the only energy possessed by the system would be that due to the momentum of the revolving dynamo and motor armatures. These would continue to run until brought to rest by friction. If the two armatures were not in electrical communication, and their magnets not omitted, this would be a purely mechanical problem at the time occupied in coming to rest would be determinable from a knowledge of the amount of bearing friction in each machine. If the armatures were in electrical communication as described, then the friction of the electromagnetic nature as described, then the friction of electromagnetic nature due to the mutual influence of magnets and currents would enter the problem; but it is certain that the time occupied in coming to rest, would be less in this case, owing to the increase of retarding friction due to electrical action. In no case could the motor and dynamo continue to run indefinitely as a self-supporting system, [illegilbe] they receive a dynamo and continually dissipate energy in friction which itself cannot practically be indefinitely reduced.
Yours very truly,
A.O. Tate
Private Secretary

Download CSV | JSON