Excerpt from Page's Magazine, Vol. 5: July, 1904 Three-phase motors cannot by any Simple means be made to run continuously at various speeds. The speed does not vary With the voltage of the current, but depends approximately on the periodicity of the current supplied, and the number of pairs of poles on the motor thus the speed of a Six-pole motor per minute With a current frequency of 50 per second is found thus The number of periods per minute divided by the num ber of the pairs of poles equals the number of revolutions per minute or (50 x 60 3 revolutions per minute. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.