A 480 delta to 120/208 wye transformer connected to a 510-volt supply circuit will result in what line-to-line voltage on the secondary side?

To determine the line-to-line voltage on the secondary side of a 480 delta to 120/208 wye transformer, we need to understand how the transformer operates and how voltages are transformed from primary to secondary.

The transformer in question has a primary voltage of 480 volts (line-to-line) in a delta configuration. The secondary side is wye-configured, providing 120 volts (line-to-neutral) and 208 volts (line-to-line). When the transformer is connected to a supply circuit at 510 volts, this voltage needs to be converted to find the secondary voltage.

First, we recognize that the primary voltage will scale based on the turns ratio of the transformer due to the differing voltages between the primary and secondary. Since the primary is at 480 volts, we can calculate the necessary voltages on the secondary side using the turns ratio.

The turns ratio can be established by comparing the primary voltage to the secondary voltage. For example, the standard line-to-line voltage of the secondary, which is 208 volts, versus the 480 volts of the primary means that the transformation factor is:

[ 480\ V \text{ (primary)} / 208\ V \text{ (secondary)} \approx 2