What is the AØ-to-CØ voltage in a 120/240-volt, 3Ø, 4-W open-delta bank of transformers?

In a 120/240-volt, 3-phase, 4-wire open-delta transformer configuration, the AØ to CØ voltage refers to the line-to-line voltage between two phases, specifically phases A and C.

In a typical 3-phase split system, the line-to-line voltage is calculated by taking the phase voltage and multiplying it by the square root of 3. However, in an open-delta configuration, the arrangement is designed to deliver 240 volts between any two phases.

For a 120/240-volt system, the phase voltage (the voltage from one phase to neutral) is 120 volts, and thus, calculating the line-to-line voltage from the phase voltages results in 240 volts between any two phases, like AØ and CØ. This is consistent with the standard voltage outputs of transformers in such setups, allowing for efficient energy distribution in residential and commercial applications.

Therefore, the AØ-to-CØ voltage in this case is indeed 240 volts.