In a 3Ø transformer bank, when primary voltage is applied, which output voltage is expected?

The expected output voltage from a three-phase transformer bank when primary voltage is applied typically depends on the configuration of the transformer and the specific transformer turns ratio. In the case of a transformer bank designed for a standard 3Ø system, 120/208 volts is a common output for a wye (or star) connected secondary.

In a wye connection, the line-to-neutral voltage is typically 120 volts, while the line-to-line voltage is 208 volts for a three-phase system. This configuration is widely used in commercial and industrial applications, providing an effective way to deliver both medium and low voltage in a single distribution system.

The other voltage options, such as 120/240 volts, 277/480 volts, and 240/480 volts, relate to different transformer configurations or serve specific applications but do not align with the typical output from a standard 3Ø transformer bank designed for general use. Consequently, while those voltages can be found in various electrical distribution setups, they are not the expected outputs for a standard three-phase transformer bank with a primary voltage applied.