Hawkins Electrical Guide v. 05 (of 10) / Questions, Answers, & Illustrations, A progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications

by N. Hawkins

Ques. What form of armature is generally used?

Ans. A stationary armature.

Ques. What difficulty is experienced with revolving armatures?

Ans. The centrifugal force being considerable on account of the high speed, requires specially strong construction to resist it, consequently closed or nearly closed slots must be used.

Ques. How is the design of the rotor modified so as to reduce the centrifugal force?

Ans. It is made long and of small diameter.

Some examples of revolving fields are shown in figs. 1,579 to 1,584. Figs. 1,577 and 1,578 show some construction details of a stationary armature of turbine alternator.

Fig. 1,583.—Westinghouse two pole parallel slot turbine alternator field.