What is the primary effect of "single-phasing" on a three-phase transformer bank?

The primary effect of "single-phasing" on a three-phase transformer bank is that it can lead to complete inoperability of the transformer bank. Single-phasing occurs when one of the three phases loses power or is disconnected. In a three-phase system, the balance among the phases is crucial for the proper operation of transformers. When one phase is lost, the transformer bank cannot function effectively, often leading to equipment shutting down or failing to operate altogether.

In addition to inoperability, single-phasing can cause significant safety and performance issues within the electrical system. While issues such as overheating and voltage imbalance may also arise from single-phasing, the immediate and most critical impact is the inability of the transformer bank to serve its intended function, which is why inoperability is the most direct consequence.