Ques. How are the coils attached?
Ans. Where the pole pieces are simply extensions of the cores without enlargement, the coils can be slipped over the ends, but some kind of clamping device is necessary to hold them in place, as for instance, the method shown in fig. 244.
In case the pole piece be made larger than the core and separate therefrom, it is put into position after the coils are in place, thus serving the double purpose of pole piece and clamp.
Ques. Describe the coil connections.
Ans. Coils are generally united in series so that the same magnetizing current may flow through all of them. The coils should be so connected that they produce alternate north and south poles.
If all the coils be similarly wound with respect to the terminals, and similarly placed; that is, so placed that the winding, considered from the coil terminal nearest the pole face, starts in all the coils in the same direction, then the connections will come at the north end and at the south end of the spools.
