The document describes a step-down transformer with a primary voltage of 6.6kV that has dropped to 6270V due to load and distance. The transformer has a ratio of 25:1 and is asked to calculate the secondary voltages at the principal tap and -5% tap. At the principal tap the secondary voltage is 250V, and at the -5% tap the secondary voltage is 264V to maintain the rated output with the lower primary voltage.