The core component of the on-load capacity-adjusting voltage-regulating transformer is suitable for rural power grids with large seasonal load changes and some urban commercial areas, development zones, industrial areas and other power distribution areas with significant day and night load changes. When the load of the power grid is light or close to no load, the project product will intelligently change the transformer from large capacity to small capacity operation, greatly reducing the line loss of the power grid and saving electric energy. The product includes a voltage regulating function, and the number of tap positions is 3/5.