Question 520Electricity & Electronics - QMED

70% to pass

In figure "2" of the diagram shown in the illustration, the three phase power transformer has a step-down turns ratio of four to one. If a three-phase 440 volt supply is connected to terminals 'A1-B1-C1’, what voltage should develop across terminals 'A2-B2-C2'? Illustration EL-0084

Diagram for USCG Electrical QMED: In figure "2" of the diagram shown in the illustration, the three phase power...

A64 volts

B110 volts

C190 volts

D762 volts

AI Explanation

The correct answer is B) 110 volts. The key information provided is that the three-phase power transformer in the diagram has a step-down turns ratio of 4:1. This means that for every 4 turns on the primary winding (connected to the 440 volt supply), there is 1 turn on the secondary winding. With a 4:1 turns ratio, the output voltage on the secondary winding (terminals A2-B2-C2) will be 1/4 of the input voltage of 440 volts, which equals 110 volts. This is the correct answer. The other options are incorrect because they do not correctly apply the 4:1 step-down turns ratio to calculate the expected secondary voltage.