It will be understood of course, that the rotation and action of the commutator must be in synchronism or in proper accord with the periods of the alternation in order to secure the desired results.
Such a disposition is represented digrammatically in Figure 3. Corresponding to the previous figures, A is the generator of alternating currents, B, B, the line and C, D, the two branches for the direct currents. In branch C are included two primary coils E, E', and in branch D are two similar primaries F, F'. The corresponding secondaries for these coils and which are on the same subdivided cores J and J', are in circuits, the terminals of which connect to opposite segments K, K' and L, L', respectively of a commutator, Brushes b b bear upon the commutator and alternately short-circuit the plates K and K' and L and L' through a connection c. It is obvious that either the magnets and the commutator or the brushes may revolve.
The operation will be understood from a consideration of the effects of closing or short-circuiting the secondaries. For example, if at the instant when a given wave of current passes, one set of secondaries be short-circuited nearly all the current flows through the corresponding primaries, but the secondaries of the other branch being open circuited, the self-induction in the primaries is highest and hence little or no current will pass through that branch.
