Question 250Electricity & Electronics - Assistant Engineer

The correct answer is B) 120 volts. In a three-phase step-down transformer with a turns ratio of 4:1, the secondary voltage will be 1/4 of the primary voltage. Since the primary voltage is 480 volts, the secondary voltage across terminals A2-B2-C2 should be 480/4 = 120 volts. The other options are incorrect because: A) 69 volts is too low for a 4:1 step-down transformer from a 480-volt primary. C) 208 volts is the line-to-line voltage, not the line-to-neutral voltage. D) 277 volts is the line-to-neutral voltage for a 480-volt, 3-phase system, but not the output of a 4:1 step-down transformer.