Fig. 186.—The Transformer completely Wound and ready for Assembling.
The regulating switches, two in number, are mounted on the lower part of the base. The contact points and the arm are cut out of sheet-brass, one-eighth of an inch thick. It is unnecessary to go into the details of their construction, because the dimensions are plainly shown in Figure 188.
The contacts are drilled out and countersunk so that they may be fastened to the base with small flat-headed wood screws.
Each switch-arm is fitted with a small rubber knob to serve as a handle. The arm works on a small piece of brass of exactly the same thickness as the switch-points. Care must be taken that the points and this washer are all exactly in line, so that the arm will make good contact with each point. There are five points to each switch, as shown in Figure 190.
Fig. 187.—Wooden Strips for mounting the Transformer on the Base.
The switch, D, is arranged so that each step cuts in or out twenty turns of the secondary, the first point being connected with the end of the winding. The second point connects with the first tap, the third contact with the second tap, the fourth contact with the third tap, and the fifth contact with the fourth tap.
Fig. 188.—Details of the Switch Parts.