150 Electrical Power Systems Technology
Voltages are developed in each stator winding as the electromagnetic field
rotates within the enclosure that houses the stator coils.
Three-Phase Connection Methods
In Figure 68, poles A’, B’, and C’ represent the beginnings of each of
the phase windings of the alternator. Poles A, B, and C represent the ends
of each of the phase windings. There are two methods that may be used to
connect these windings together. These methods are called wye and delta
connections.
Three-phase Wye-connected Generators
The windings of a three-phase generator can be connected in a wye
configuration by connecting either the beginnings or the ends of the wind-
ings together. The unconnected ends of the windings become the three-
phase power lines from the generator. A three-phase wye-connected gen-
erator is illustrated in Figure 6-10. Notice that the beginnings of the wind-
ings (poles A’, B’, and C’) are connected together. The other ends of the
windings (poles A, B, and C) are the three-phase power lines that are con-
nected to the load to which the generator will supply power.
Three-phase Delta-connected Generators
The windings of a three-phase generator may also be connected in
a arrangement, delta as shown in Figure 6-11. In the delta configuration, the
Figure 6-10. Simplified drawing of the stator of a three-phase generator that is
connected in a wye configuration