Question 33Electricity & Electronics - Assistant Engineer

The correct answer is D) A few shorted turns in the primary winding. When a transformer is configured as a step-down transformer (480/120 VAC), a reduction in the primary winding voltage should result in a proportional reduction in the secondary winding voltage. However, if there are a few shorted turns in the primary winding, it would cause the primary winding voltage to drop more than expected, resulting in a lower than expected secondary winding voltage (141 VAC instead of the expected 120 VAC). The other options are incorrect because an open primary winding would result in no output voltage, and an open or shorted secondary winding would not cause the observed reduction in secondary voltage.