TAP Services(865) 919-6674

26307-11 Transformers

1. A three-phase, four-wire system that has the advantage of providing three-phase power and allowing lighting to be connected between any of the secondary phases and the neutral would have a(n) ________.

Question 1 of 25

2. Transformer cores support ________.

Question 2 of 25

3. To ensure maximum safety in a control transformer, the secondary control circuit is ________.

Question 3 of 25

4. Which of the following types of transformers must be installed in a vault?

Question 4 of 25

5. Most control transformers are ________.

Question 5 of 25

6. Which section of the NEC® contains transformer nameplate requirements?

Question 6 of 25

7. Which of the following refers to the condition in which two circuits share the energy of one of the circuits?

Question 7 of 25

8. Refer to the figure above. Which taps should be connected to increase the secondary voltage by 5%?

Question 8 of 25

9. What is the voltage of the secondary in a transformer with 200 turns in the primary, 20 turns in the secondary, and an input voltage of 2,400V?

Question 9 of 25

10. Which of the following types of transformers can be ventilated, air-cooled, or sealed?

Question 10 of 25

11. The NEC® requires that conductors connected to the high leg of a four-wire delta system be color-coded with what color of insulation or tape?

Question 11 of 25

12. What type of transformer provides 120V between the center -tapped terminal and each ungrounded terminal on either side and 240V across the full winding of each phase?

Question 12 of 25

13. What type of transformer has more turns in the primary than the secondary?

Question 13 of 25

14. To improve the power factor of a circuit that has high inductive reactance, which of the following would be added to the circuit?

Question 14 of 25

15. The secondary voltage in a transformer can be increased or decreased by connecting various ________.

Question 15 of 25

16. A lagging current for a motor or inductive device is represented by a power factor of ________.

Question 16 of 25

17. When voltage is stepped down in a transformer, what happens to the current in the same circuit?

Question 17 of 25

18. Other than surge capacitors or capacitors that are part of another apparatus, the chief use of capacitors is to ________.

Question 18 of 25

19. Refer to the figure above. A multi-tap transformer has 1,620 turns in the primary. There are 40 turns between each tap. Taps 6 and 3 are connected. Which taps must be connected to reduce output voltage by 5%?

Question 19 of 25

20. What components are installed to increase the power factor and decrease the cost of electricity caused by large inductive loads?

Question 20 of 25

21. What forces are always present in an AC circuit?

Question 21 of 25

22. The installation of resistors and reactors is covered in ________.

Question 22 of 25

23. Which winding of a transformer is connected to the load?

Question 23 of 25

24. Capacitors are covered in ________.

Question 24 of 25

25. Which of the following best describes a transformer that increases the voltage on the primary from 120V to 1,200V?

Question 25 of 25