Which type of transformer bank is indicated when the secondary voltage is 240 volts?

When a system indicates a secondary voltage of 240 volts, it commonly refers to residential and light commercial applications that typically use split-phase systems. In the context of transformers, an open delta configuration can support this voltage.

An open delta transformer bank typically consists of two transformers arranged in a way that they create a three-phase output from a two-phase input. This setup is often used to supply a 240-volt output, which aligns with the common voltage levels found in many electrical systems.

In contrast, a closed delta configuration generally connects three transformers, which would typically yield different voltage outputs. A single-phase transformer would not generally provide a multiple-phase system or the specific characteristics of a three-phase system, and a three-phase transformer arrangement, while capable of operating at 240 volts under certain conditions, doesn't specifically indicate an open delta setup. Therefore, the open delta arrangement is the most relevant option when discussing a secondary voltage of 240 volts in this context.