Figs. 2,161 to 2,163.—Evolution of the three phase three wire system. Fig. 2,161 is a conventional diagram of the three phase six wire system shown in fig. 2,160. A wire is connected to both ends of each phase winding, giving six conductors, or three independent two wire circuits. In place of the wires running from A, B, and C, they may be removed and each circuit provided with a ground return as shown in fig. 2,162. The sum of the three currents being zero, or nearly zero, according to the degree of unbalancing, the ground return may be eliminated and the ends A, B, and C of the three phase winding connected, as in fig. 2,163, giving the so called star point.
Fig. 2,166 is a view of an elementary three phase three wire star connected alternator.
Ques. What are the pressure and current relations of the star connected three wire system?
Figs. 2,164 and 2,165.—Three phase four wire star connected alternator and conventional diagram showing pressure and current relations.
Figs. 2,166 and 2,167.—Three phase star connected alternator, and conventional diagram showing pressure relations.
Ans. These are shown in the diagram, fig. 2,166 and 2,167.