34

INVENTIONS OF NIKOLA TESLA.

through the same phases as the coils in some of the generatorsalready shown, and it is obviously only necessary to utilize themin pairs or sets to operate a Tesla converter by extending thesegments of the commutators belonging to each pair of coils andcausing a collecting brush to bear on the continuous portion ofeach segment. In this way two or more circuits may be takenoff from the generator, each including one or more pairs or setsof coils as may be desired.

In Fig. 26 i i represent the armature coils, t t the poles of thefield magnet, and f the shaft carrying the commutators, whichare extended to form continuous portions a b o d. The brushes

Fig. 27.

bearing on the continuous portions for taking off the alternatingcurrents are represented by a' V c’d'. The collecting brushes,or those which may be used to take off the direct current, aredesignated by m m. Two pairs of the armature coils and theircommutators are shown in the figure as being utilized; but allmay be utilized in a similar manner.

There is another well-known type of machine in which threeor more coils, a' n' o', on the armature have a common joint,the free ends being connected to the segments of a commutator.This form of generator is illustrated in Fig. 27. In this case eachterminal of the generator is connected directly or in derivationto a continuous ring, a b c, and collecting brushes, a' b' c', bearing