File:Britannica Dynamo 39.jpg

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Summary

Description
English: Quarter-phase alternator. If the phases be diagrammatically represented by the relative angular position of the coils in this figure, the current in the coils A and B differs in phase from the current in the coils C and D by a quarter of a period or 90°; hence if the two wires b and d be replaced by the single wire bd, this third wire will serve as a common path for the currents of the two phases either outwards or on their return. At any instant the value of the current in the third wire must be the vector sum of the two currents in the other wires, and if the shape of the curves of instantaneous E.M.F. and current are identical, and are assumed to be sinusoidal, the effective value of the current in the third wire will be the vector sum of the effective values of the currents in the other wires; in other words, if the system is balanced, the effective current in the third wire is √2, or 1.414 times the current in either of the two outer wires.
Date
Source Encyclopædia Britannica, 1911
Author Encyclopædia Britannica, Volume 8, Slice 9., available freely at Project Gutenberg

Licensing

Public domain This image comes from the 13th edition of the Encyclopædia Britannica or earlier. The copyrights for that book have expired in the United States because the book was first published in the US with the publication occurring before January 1, 1929. As such, this image is in the public domain in the United States.
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current20:16, 17 February 2011Thumbnail for version as of 20:16, 17 February 2011405 × 151 (12 KB)Keith Edkins=={{int:filedesc}}== {{Information |Description={{en|Quarter-phase alternator. If the phases be diagrammatically represented by the relative angular position of the coils in this figure, the current in the coils A and B differs in phase from the current i

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