What is the primary function of a rotary inverter?

The primary function of a rotary inverter is to convert direct current into alternating current, specifically into a standardized voltage and frequency required for various electrical systems, such as 115 volts at 400 cycle (or hertz) power. This capability is essential in applications where the source of electrical energy is direct current, such as batteries or DC generators, and there is a need for the more common AC power used in most equipment and systems.

A rotary inverter operates on the principle of mechanical to electrical energy conversion, often using a rotating mechanism to facilitate this change. It is designed to provide stable and reliable power output suitable for use in aircraft and other environments where alternating current is necessary.

In contrast, other choices address different electrical functions. The option about converting AC to DC describes the process of a rectifier. Generating AC from mechanical energy is primarily associated with alternators rather than inverters. The measurement of electrical power in watts involves entirely different components and tools, such as wattmeters, which do not pertain to the function of a rotary inverter. This clarification helps reinforce why the answer regarding the conversion of direct current to 115 volts, 400 cycle power aligns with the rotary inverter's main role.