If a transformer has an impedance of 2%, this means that the secondary voltage will be limited by _____% when the transformer is at full load

• A. 1%
• B. 2%
• C. 3%
• D. 4%

Answer: (B)

Impedance in a transformer is the series element that causes a voltage drop when current flows. The percent value tells you how large that drop is, relative to the rated voltage, at full-load current. A 2% impedance means the voltage drop under full load is about 2% of the rated voltage. So the secondary voltage is limited by roughly 2% when the transformer is fully loaded. The other options would imply smaller or larger drops than the defined impedance.