Fig. 1,916.—Diagram of elementary transformer with non-continuous core and connection with single phase alternator. The three essential parts are: primary winding, secondary winding, and an iron core.
Ques. What name is given to the coil in which a current is induced?
Ans. The secondary winding.
Similarly, the current from the source (alternator) is called the primary current and the induced current, the secondary current.
Ques. What is the objection to the elementary transformer shown in fig. 1,916?
Ans. The non-continuous core. With this type core, the flux emanating from the north pole of the bar has to return to the south pole through the surrounding air; and as the reluctance of air is much greater than that of iron, the magnetism will be weak.
Ques. How is this overcome?
Ans. By the use of a continuous core as shown in fig. 1,917.
Ques. Is this the best arrangement, and why?
Ans. No. If the windings were put on as in fig. 1,917, the leakage of magnetic lines of force would be excessive, as indicated by the dotted lines. In such a case the lines which leak through air have no effect upon the secondary winding, and are therefore wasted.