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26307-11 Transformers

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

Question 1 of 25

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

Question 2 of 25

3. Most control transformers are ________.

Question 3 of 25

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

Question 4 of 25

5. Capacitors are covered in ________.

Question 5 of 25

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

Question 6 of 25

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

Question 7 of 25

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

Question 8 of 25

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

Question 9 of 25

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

Question 10 of 25

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

Question 11 of 25

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

Question 12 of 25

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

Question 13 of 25

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

Question 14 of 25

15. Transformer cores support ________.

Question 15 of 25

16. 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 16 of 25

17. 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 17 of 25

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

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

Question 20 of 25

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

Question 21 of 25

22. 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 22 of 25

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

Question 23 of 25

24. 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 24 of 25

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

Question 25 of 25