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NT[_2_] NT[_2_] is offline
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Default Could you be an electrician in 1912?

On Jul 27, 6:17*pm, NT wrote:
Could you be an electrician in 1912? Check your knowledge - Wiring &
lighting questions

http://chestofbooks.com/architecture...ry-Building-7-...

Review Questions On The Subject Of Electric Wiring

1. Explain the three-wire system of wiring.

2. In case a test shows excessive leakage, or a ground or short
circuit, how would you locate the trouble and remedy it?

3. Describe the construction and use of outlet-boxes.

4. What is the principal difference between alternating and direct-
current circuits, so far as concerns the wiring system?

5. Compare the advantages of the two-wire and three-wire systems of
wiring.

6. Under what general heads are approved methods of wiring classified?

7. A single-phase induction motor is to be supplied with 25 amperes at
220volts; alternations 12,000 per minute; power factor .8. The
transformer is 200 feel from the motor, the line consisting of No. 4
wire, 9 inches between centers of conductors. The transformer reduces
in the ratio 2,500/ 250, has a capacity of 30 amperes at 220 volts,
and, when delivering this current and voltage, has a resistance-E.M.
F. of 2.5 per cent, and a reactance E. M. F. of 5 per cent. Calculate
the crop. (Use table and chart.)

8. What are the distinctive features of the different kinds of metal
conduit?

9. Suppose power to be delivered, 300 K. W.; E. M. F. to be delivered,
2,200 volts; distance of transmission, 15,000 feet; size of wire, No.
00; distance between wires, 24 inches; power factor of load, .7;
frequency, 100 cycles per second. Calculate line loss and crop in per
cent of E, M. F. delivered. (Use table and chart.)

10. In installing A. C. circuits, what requirements are insisted on as
to the placing of conductors in conduits?

11. Describe the manufacture, use, and special advantages of the
different kinds of armored cable.

12. Describe three different methods of testing? Which is to be
preferred?

13. What conditions determine whether a two-wire or three-wire system
of wiring should be used?

14. In locating cut-out cabinets and distributing centers, what
requirements should be fulfilled?

15. What is "knob and tube" wiring? Explain its use and discuss its
advantages or disadvantages.

16. How far apart should insulators be placed?

17. What tests should be made before an electric wiring equipment is
finally passed for acceptance? Give reasons.

18. What regulations govern the use of fibrous tubing?

19. What is meant by mutual induction?

20. What are the advantages and disadvantages of overhead linework as
compared with underground linework?

21. Describe and illustrate by sketches proper methods of supporting
and protecting conductors.

22. Discuss the advantages of running conductors exposed on
insulators.

23. Illustrate by diagram, proper and improper methods of grouping
conductors of two two-wire circuits.

24. What dangers are inherent in the use of moulding? What precautions
should be taken to avoid them?

25. Describe the proper methods of laying out branch circuits, (a) in
fireproof buildings; (b) in wooden frame buildings. Give sketches.

26. What methods of installing wiring are best adapted for the
following classes of buildings, (a) fireproof structures; (b) mills,
factories, etc.; (c) finished buildings; (d) wooden frame buildings?

27. What is skin effect? Its bearing on the problem of wiring?

28. In selecting runways for mains and feeders, what precautions
should be taken?

Review Questions On The Subject Of Electric Lighting

1. State the current, voltage, candle-power, and efficiency of the
incandescent lamp most commonly used.

2. What do you understand by the "smashing pint"?

3. Give the main points of difference between the three forms of arc
lamp mechanism.

4. Mention the three principal parts of the Nernst lamp.

5. Describe with sketch the anti-parallel system of feeding.

6. Prove the law that illumination varies inversely with the square of
the distance.

7. Why is arc light photometry a more difficult .problem than
incandescent?

8. Calculate the illumination three feet above the floor at the center
of a room 18 feet square and 12 feet high, lighted by four 10-candle-
power lamps 9 feet above the floor at the center of the side walls,
assuming the coefficient of reflection to be 50%.

9. What material is used for the filament of incandescent lamps?
Explain why.

10. From the curve given in Fig. 4, determine the efficiency which
corresponds to the temperature of 1300o Centigrade.

11. What is the object of double carbons in an arc lamp?

12. What is meant by mean spherical candle-power?

13. What is the function of the heater in the Nernst lamp?

14. Describe the Bunsen Photometer.

15. How does the lighting of public halls differ from that of
residences?

16. Why cannot platinum wire be used for the filament of incandescent
lamps?&9632;

17. In a direct-current arc lamp, which carbon burns away the more
rapidly?

18. How are arc lamps rated?

19. What are the important advantages of the two-wire parallel system
of distribution?

20. Name and describe the most desirable standard for photometric
measurements.

21. How many measurements should be taken in the determination of
spherical intensity?

22. What is meant by flashing? Explain.

23. Define emissivity.

24. If the voltage of an incandescent lamp be increased 4% above
normal, what is the effect on the candle-power, efficiency and light?

25. Explain the Cooper-Hewitt lamp, stating the two methods of
starting.

26. Compare the open and enclosed arc lamps.

27. Why is the positive carbon placed above the negative in a direct-
current arc lamp?

28. Sketch and name the different forms of incandescent lamp
filaments.

29. Under what conditions can a 3.1-watt incandescent lamp be used ?

30. What is the function of the arc lamp mechanism?

31. What are the advantages of the three-wire system?

32. Why is it necessary to exhaust the bulb of an incandescent lamp?

33. At what point in their life should incandescent lamps be
replaced ?

34. What is the object of a resistance in series with the arc lamp in
constant-potential direct-current systems?

35. Name the advantages of the Nernst lamp.

3G. What sort of lamps and of what candle-power should be used in
residence lighting?

37. Give the characteristics of the Cooper-Hewitt lamp.

38. What will be the external resistance on a 110 volt constant-
potential system, if the load consists of 437 lamps of 16 candle-
power?

NT



There's another electrician's questionnaire from an 1899 book on the
same site, if anyone's really determined. It didnt look so
enlightening though.


NT