Which of the following is an advantage of using a three-phase motor?

Using a three-phase motor offers several benefits, one of which is more uniform torque delivery. This is primarily due to the nature of three-phase power. In a three-phase system, power is delivered continuously, which results in a smoother and more consistent torque output compared to single-phase motors. The three phases of current interact at different angles, creating a rotating magnetic field that improves the motor's efficiency and performance. This characteristic is particularly advantageous in applications that require reliable and consistent operation, such as conveyor systems or industrial machinery.

In contrast, while options like lower operating costs, ease of maintenance, and smaller physical size can also be considered benefits under certain conditions, they are not inherent advantages specifically tied to the operation and performance dynamics of three-phase motors. For example, while three-phase motors can be more efficient, operating costs also depend on other factors like energy prices and system design, and maintenance routines can vary widely. Additionally, the physical size of three-phase motors isn't necessarily smaller; in fact, they may be larger than their single-phase counterparts for the same power output. Thus, option B stands out as the most defining characteristic of three-phase motors.