Ques. How is this obtained?
Ans. Because of the mechanical difficulty of accurately locating the parts, the equivalent result is secured by arranging the stationary element in one of the two machines so that it can be given a small angular shift.
Transformation of Phases.—In alternating current circuits it is frequently desirable to change from one number of phases to another. For instance, in the case of a converter, it is less expensive and more efficient to use one built for six phases than for either two or three phases.
Fig. 2,174.—View from roof of power house of the Schaghticoke-Schenectady transmission line, showing anchor poles, strain insulators, lightning arrester horn gap and line entrance bushings.
The numerous conditions met with necessitate various phase transformations, as
- 1. Three phase to one phase;
- 2. Three phase to two phase;
- 3. Two phase to six phase;
- 4. Three phase to six phase.
These transformations are accomplished by the numerous arrangements and combinations of the transformers.
Fig. 2,175.—Three phase to one phase transformation with two transformers. The diagram shows the necessary connections and the relative pressures obtained.