In a closed wye/delta bank, the "lighter" transformer carries what fraction of the single-phase load?

In a closed wye/delta transformer bank, each transformer in the bank works together to share the load equally. However, when referring to a "lighter" transformer, which typically indicates a transformer that is carrying less load compared to the others, it is essential to understand how load is distributed in such systems.

For a three-phase system, the total load can be divided among the three transformers. Each transformer can carry up to one-third of the total load, but in a scenario where a transformer is designated as "lighter," it means that not all transformers are carrying equal loads.

In the case of a "lighter" transformer, it typically carries 2/3 of the total load, which is characteristic when considering how loads are distributed in a delta configuration where one transformer may handle a slightly lower share while still being utilized significantly. This way, the remaining two transformers would compensate for the load, allowing the configuration to maintain balance while ensuring that the entire system operates effectively.

Ultimately, this approach to load distribution emphasizes the capacity of each transformer to share the overall load and the principle that in such configurations, when one unit is lighter, it commonly would carry approximately 2/3, with the expectations that the remaining transformers would manage the rest of the