Lesson 1/Learning Event 2
Alternate polarity occurs on successive poles. Pole excitation current is obtained through slip rings.
The advantages of the wound-pole alternator are a wide-speed range: output current windings are
stationary, and the slip rings carry low field excitation current. Disadvantages are: brushes and slip
rings wear, are affected by contamination, produce contaminating carbon dust, may cause voltage
modulation, and are not reliable for high-temperature, high-altitude, or high-speed applications.