Fig. 1,752.—Fairbanks-Morse squirrel cage armature with cast-on rings showing inspection grooves. The method consists in fusing the ends of the inductors into an end ring of a special composition, thereby producing a perfect electrical and mechanically strong joint. In this process the armature with its bars in place is put into a mould and the molten metal poured around the inductors, melting their ends and effectually fusing them into the body of the ring. The ring is then turned down to finished size and polished. An inspection groove is cut as shown to indicate that the fusion is complete and the joint perfect.
Fig. 1,753.—Section of Fairbanks-Morse "cast-on" joint showing union of end ring and inductor. The view shows the V-shape inspection groove as described in fig. 1,752.
Broadly, the field magnets of induction motors consists of:
- 1. Yoke or frame;
- 2. Laminæ, or core stampings;
- 3. Winding.
Fig. 1,754.—Richmond field construction for polyphase induction motors, showing style of winding for use with squirrel cage and wound armature types.
Ques. What is the construction of the yoke and laminæ?
Ans. They are in every way similar to the armature frame and core construction of revolving field alternators.