For a delta bank serving mostly 120-volt loads, how much current must each transformer supply?

In a delta bank configuration serving 120-volt loads, each transformer typically supplies approximately a third of the total load current. This is due to the way the delta connection distributes current among the transformers. In a delta system, the phase voltages are equal to the line voltages, which means that each phase (transformer) only sees part of the total load current.

When calculating the load current for each transformer in a three-phase delta system, the load is divided across the three transformers. Since the current supplied by each transformer is a function of the phase relationship and load, each transformer effectively handles only one-third of the total load, assuming balanced loading. Therefore, if you had a specific total load current, you would divide that by the three phases to determine the current through each transformer.

This distribution method is efficient and helps in balancing the load among the transformers, ensuring that no single transformer is overloaded while providing adequate supply to the 120-volt loads connected to the system.