Question 251Electricity/Electronics - Assistant Engineer70% to pass
The turns ratio of the tapped step-down transformer shown in figure "C" of the illustration is four to one and all taps are evenly spaced. If 120 volts were applied to terminals 'H1' and 'H3', what would appear at 'X1' and 'X2'? Illustration EL-0082
AI Explanation
The correct answer is A) 15 volts.
In a tapped step-down transformer, the turns ratio determines the output voltage. With a turns ratio of 4:1, the output voltage will be one-fourth of the input voltage. Since the input voltage is 120 volts, the output voltage across terminals X1 and X2 will be 120 volts / 4 = 15 volts.
The other options are incorrect because B) 30 volts is double the actual output, C) 480 volts is four times the input voltage, and D) 960 volts is eight times the input voltage, all of which do not match the 4:1 turns ratio of the transformer.
Related Questions
#249 In figure "1" of the diagram shown in the illustration, the three phase step-down power transformer has a 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 #250 In figure "2" of the diagram shown in the illustration, the three phase step-down power transformer has a turns ratio of four to one. If a three-phase 480 volt supply is connected to terminals "A1-B1-C1", what voltage should develop across terminals "A2-B2-C2"? Illustration EL-0084 #252 In figure "4" of the diagram in the illustration, the three phase step-down power transformer has a turns ratio of five to one. If a three-phase 4160 volt supply is connected to terminals "A1-B1-B2", what voltage should develop across terminals "A2- B2-C2"? Illustration EL-0084 #253 If the motor shown in the illustration will not start when the "off-run" switch is placed in the run position, which of the listed components should be checked FIRST? Illustration EL-0017 #254 The motor fails to start on an attempted startup. With the start button depressed, a voltmeter reading between 1 and 5, as in figure "A" shown in the illustration, indicates line voltage available to the control circuit, what should be your next step in the troubleshooting process? Illustration EL-0007