File:Core-less induction coils in telephone service (1907) (14569515577).jpg

Identifier: corelessinductio00smit (find matches)
Title: Core-less induction coils in telephone service
Year: 1907 (1900s)
Authors: Smith, Claude E Stewart, Walter M
Subjects: Induction coils Telephone Telephone systems Theses
Publisher:
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
turns of #36 copx)er wire, giving a resistance of188 ohms, and as a primary, 3J turns of # 25 copper v;iro v;ound ona 39 i:ich bicycle rim. This coil when compared with the largecoreiess coil of seperate windiiigs, was found to transmit sound ofabout fourty percent loss intensity than that of the large coil.It vms however,quite distinct and clear. It is very likely thatshould v/e have wound the secondary of ten-inch diameter with asmuch and even more wire, than the twenty-eight inch secondary, wemight have had more satisfactory results. The inductive effect produced inthe secondarys of these core-less coils, was Electro-magnectic. As the current in the primaryfluctuates, the field of force about the primary becomes more in- ■tense, and will expand while the current strength is increasing.Whenever there is such a relative movement betv/een a conductor and the lines of force of a magnetic field, as to cause the conductor,( the secondary ) to cut the lines, or the lines to cut the con-
Text Appearing After Image:
7. ductor, an olectro motive force is sot up in the conductor, whichtends to cause a current to flow. The direction or the electro-motive force will depend upon the direction of the lines, and themovement of the conductor, and its value will depend on the rateof cutting. It se.iins that the most probable field for this kind of coilwould be in the high tension work, especially on inter-urban roads.The diagram here shown would present a possible way of connectingup to the high tension so as to insure some safety to the operator.There has been some experimental work carried on v/ith cored coilsover comparatively high tension , and one of the difficulties metwith was the safety of the operator. Circuit if 1* is an ordinarytelephone set communicating with circuit #2. by the usual indiic-tion coil. Circuit ^ 2, might ue grounded at some point as shown,in order to insure the operator against an excessive voltage.This circuit would very likely carry a large current and low elec-tro-motive for

Note About Images