AC Generator Connections

AC GENERATOR OPERATION AC Generators AC Generator Connections Figure 8 Delta Connection As shown in Figure 7, there are six leads from the armature of a three-phase generator, and the output is connected to an external load. In actual practice, the windings are connected together, and only three leads are brought out and connected to the external load. Two means are available to connect the three armature windings. In one type of connection, the windings are connected in series, or delta-connected (D) (Figure 8). In a delta-connected generator, the voltage between any two of the phases, called line voltage, is the same as the voltage generated in any one phase. As shown in Figure 9, the three phase voltages are equal, as are the three line voltages. The current in any line is times the phase current. You can 3 see that a delta-connected generator provides an increase in current, but no increase in voltage. An advantage of the delta-connected AC generator is that if one phase becomes damaged or Figure 9 Characteristics of a Delta-Connected Generator open, the remaining two phases can still deliver three-phase power. The capacity of the generator is reduced to 57.7% of what it was with all three phases in operation. ES-10 Page 12 Rev. 0