If the secondary voltage is 120/240 or 240/480 volts, what is the configuration?

The configuration for secondary voltage ratings of 120/240 volts or 240/480 volts is typically a Delta configuration. In a Delta configuration, the three phases are connected in a closed loop, forming a triangle or "delta" shape. This allows for higher line voltages and provides both 240-volt and 120-volt outputs, which is crucial for various residential and commercial applications.

In the case of 240/480 voltage systems, the Delta setup efficiently transmits power and can accommodate a range of electrical loads. The ability to tap into the phases allows for 120-volt service when necessary, making it very versatile for different electrical requirements.

While Wye and Star are often used interchangeably in some contexts, they are primarily suited for different voltage and grounding scenarios; they support lower voltage levels when necessary (e.g., neutral grounding). The Ring configuration is less common and not typically associated with standard secondary voltage ratings like those mentioned. Therefore, the Delta configuration stands out as the correct answer in this context.