Which statement regarding the factors that determine the frequency of an alternator is correct?

The correct statement is that the frequency of an alternator involves both slip rings and rotor speed. The frequency produced by an alternator is determined by the speed at which the rotor spins and the number of poles in the stator winding of the alternator. As the rotor rotates, it generates an alternating current in the stator, and the speed of this rotation directly influences the frequency of the AC output.

The slip rings play a role in facilitating the flow of current from the rotor to the external circuit, but they do not impact the frequency directly. Instead, it is the combination of rotor speed (the speed at which the magnetic field rotates) and the design of the alternator (such as the number of poles) that ultimately determines the frequency. The relationship can be expressed in the formula:

Frequency (in Hz) = (Poles × RPM) / 120

This formula clearly indicates that both the rotor speed and the number of poles are critical factors in determining the frequency of the generated current. Understanding this relationship is important for both the operation of alternators and for maintaining their efficiency and functionality in electrical systems.