The machine proper, as far as electrical features are concerned, is now complete, although considerable work is still necessary 01 the connections between the fields and to the terminal blocks at the side of the machine. There are, however, the mechanical features of the bearings and pedestals which are taken care of in the two following plates.
The bearings proper, Figs. 1, 2, 5, and 6, are self-aligning, that is, they are constructed so as to adjust themselves automatically to the position of the shaft. This is accomplished by making the bearing casting with a hub on the outside which is turned to a spherical shape. The bearing pedestal and caps are then constructed so as to fit these pieces into a corresponding spherical support. This makes in effect a ball-and-socket arrangement, which allows considerable adjustment in any direction, so that it is not necessary to align the two pedestals accurately, either horizontally or vertically.
The scheme for keeping oil on the bearings is one commonly used for machines of this class. The oil is contained in the receptacle in the pedestal. The bearings have slots cut through, which arrangement allows oil rings to rest on the top surface of the shaft, the bottom of the ring dipping into the oil in the receptacle. As the shaft revolves, the rings pick up oil and transmit it to the top of the shaft. Grooves are cut in the babbitt metal forming the bearing surface so that this oil can flow over the whole surface of the bearing. It will be necessary, of course, for the draftsman to detail all these parts and to arrange them so that they will be easily constructed in the shop and easily assembled at any time afterward.
It will be noted that the bearings are lined with babbitt metal and that the two halves of the iron shell are cast with ridges so arranged that when the metal is in place it is held solidly with no chance for slipping or turning. This metal, of course, is poured into the bearing with the shaft in place. It will be seen that the openings in the top half of the bearing are so arranged that the babbitt metal can be poured in conveniently.
It is necessary, of course, to cut away the metal at this point after it is cold in order to provide a peep hole and in order to clear the slots for the oil rings. The inside surfaces, being shaped to fit after the metal is cold, have grooves for oil transmission cut in after the bearing is complete. Since these operations cannot be shown in the drawing, no information is given except as to the metals being used.
The details of the two bearings are much the same but, nevertheless, they are very carefully brought out in the drawings in order to give the foundryman and shopman the necessary information. The parts of the 4½X13½ inch bearing are made larger and stronger as this bearing is subject to greater strains, being on the side where the shaft coupling is placed.