On a transformer nameplate, what HV number indicates the rated secondary voltage?

The rated secondary voltage on a transformer nameplate is indicated by the lower voltage rating, also referred to as the "little number." This number reflects the voltage output that the transformer will provide at its secondary winding when the primary side is energized. In power transformer applications, the high-voltage (HV) side is typically the primary side, while the low-voltage (LV) side is the secondary.

Thus, in the context of transformer nameplates, the lower voltage rating corresponds to the secondary voltage, which is critical for ensuring that electrical devices connected to the transformer receive the appropriate voltage. Understanding this allows linemen and electrical professionals to properly select transformers for specific applications in systems where voltage requirements must be met to ensure safety and functionality.