Multi-phase Currents

—Multi-phase currents are two or more separate and distinct of currents not differing in any way from the low current derived from an ordinary “single phase” alternator. Their peculiarity lies in the fact that they have different strengths at a given instant of time. Ta the two-phase system, when one of the currents is at zero value, the other has its maximum value, or the currents are displaced in phase, whence the expre ton two-phase. If two identical simple alternators have their armature shafts coupled in such a manner, but when a given armature coil on one is directly under a field pole, the corresponding coil on the other is midway between two poles of its field, the two currents generated will differ in phase by a half alternation, and will be two-phase currents; similarly, three-phase currents could be generated by coupling the armatures cf three simple alternators so that the corresponding coils on each are equally ‘‘staggered’’ with respect to each other. Two-phase and three-phase currents differ in this respect; the two-phase system requires four wires to connect the generators with the motors, and their action is that of two distinct and separate circuits through which are pa ing simple alternating currents of electricity which act upon the revolving part of the motor like the two cranks on a cro connected engine at right angles Se other, or one 90 degrees in advance of the other. The three-phase method of employing the alternating current requires only three wires, and for transmitting electrical energy in large amounts long distances for power purposes it is an ideal system.