How can you identify the lighter pot in a transformer bank?

When identifying the lighter pot in a transformer bank, the characteristic that stands out is that it has a grounded x2. In transformer configurations, particularly in three-phase systems, the grounding of the secondary side or x2 connection is an important aspect that indicates the neutral point of the transformer.

This grounding serves not only a safety purpose by providing a path for fault currents to safely dissipate, but it also stabilizes the voltage levels across the other phases. In a transformer bank, the pot that has this grounding may typically be the one that is designed to handle a smaller load or less capacity, and as a result, is considered the "lighter" pot in comparison to the others.

The other options, while they may suggest some physical or electrical properties of the pots in the bank, do not directly ensure identification based on their load or function in the system. For instance, while a pot connected at the bottom or the one that has the lowest impedance may have certain characteristics, they do not specifically indicate that it is the lighter pot. Similarly, while size might be an observable trait, it does not guarantee lighter capacity since design variations can affect physical dimensions without correlating directly to the pot's rated capacity.