In AC generators, slip rings serve to transfer current without reversing polarity.

In AC generators, slip rings serve to transfer current without reversing polarity.

• A. Coils
• B. Wires
• C. Brushes
• D. Slip rings

Answer: (D)

The concept being tested is how an AC generator delivers the alternating current from a rotating coil to the outside circuit. In an alternator, the ends of the rotor coil are connected to two conducting rings that rotate with the coil. Stationary brushes press on these slip rings to carry the current away. Because the coil’s induced EMF reverses every half turn, the current that reaches the external circuit also reverses, giving AC, while the slip rings themselves simply provide a continuous connection without flipping the polarity. If a commutator were used instead, it would switch connections to the external circuit to produce DC, which is not what AC generators aim for.

The concept being tested is how an AC generator delivers the alternating current from a rotating coil to the outside circuit. In an alternator, the ends of the rotor coil are connected to two conducting rings that rotate with the coil. Stationary brushes press on these slip rings to carry the current away. Because the coil’s induced EMF reverses every half turn, the current that reaches the external circuit also reverses, giving AC, while the slip rings themselves simply provide a continuous connection without flipping the polarity. If a commutator were used instead, it would switch connections to the external circuit to produce DC, which is not what AC generators aim for.