What is the main function of a generator?

The main function of a generator is to convert mechanical energy into electrical energy. This process typically involves the use of a rotating component called a rotor, which interacts with a magnetic field to induce an electric current in conductors. When mechanical energy, such as that from a turbine driven by steam, water, or wind, is applied to the rotor, it causes the movement necessary for the generation of electricity.

In this context, the other options are not aligned with the primary function of a generator. For instance, converting electrical energy into mechanical energy describes the operation of devices like electric motors, while storing electrical energy for later use pertains to batteries or capacitors. Regulating voltage levels in circuits relates to transformers or voltage regulators, which serves a distinct function from that of a generator. Therefore, option B accurately captures the fundamental role of a generator in the generation of electrical power.