Could you be an electrician in 1912? Check your knowledge - Wiring & lighting questions
- Explain the three-wire system of wiring.
- In case a test shows excessive leakage, or a ground or short circuit, how would you locate the trouble and remedy it?
- Describe the construction and use of outlet-boxes.
- What is the principal difference between alternating and direct- current circuits, so far as concerns the wiring system?
- Compare the advantages of the two-wire and three-wire systems of wiring.
- Under what general heads are approved methods of wiring classified?
- A single-phase induction motor is to be supplied with 25 amperes at
- What are the distinctive features of the different kinds of metal conduit?
- Suppose power to be delivered, 300 K. W.; E. M. F. to be delivered,
- In installing A. C. circuits, what requirements are insisted on as to the placing of conductors in conduits?
- Describe the manufacture, use, and special advantages of the different kinds of armored cable.
- Describe three different methods of testing? Which is to be preferred?
- What conditions determine whether a two-wire or three-wire system of wiring should be used?
- In locating cut-out cabinets and distributing centers, what requirements should be fulfilled?
- What is "knob and tube" wiring? Explain its use and discuss its advantages or disadvantages.
- How far apart should insulators be placed?
- What tests should be made before an electric wiring equipment is finally passed for acceptance? Give reasons.
- What regulations govern the use of fibrous tubing?
- What is meant by mutual induction?
- What are the advantages and disadvantages of overhead linework as compared with underground linework?
- Describe and illustrate by sketches proper methods of supporting and protecting conductors.
- Discuss the advantages of running conductors exposed on insulators.
- Illustrate by diagram, proper and improper methods of grouping conductors of two two-wire circuits.
- What dangers are inherent in the use of moulding? What precautions should be taken to avoid them?
- Describe the proper methods of laying out branch circuits, (a) in fireproof buildings; (b) in wooden frame buildings. Give sketches.
- 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?
- What is skin effect? Its bearing on the problem of wiring?
- In selecting runways for mains and feeders, what precautions should be taken?
Review Questions On The Subject Of Electric Lighting
- State the current, voltage, candle-power, and efficiency of the incandescent lamp most commonly used.
- What do you understand by the "smashing pint"?
- Give the main points of difference between the three forms of arc lamp mechanism.
- Mention the three principal parts of the Nernst lamp.
- Describe with sketch the anti-parallel system of feeding.
- Prove the law that illumination varies inversely with the square of the distance.
- Why is arc light photometry a more difficult .problem than incandescent?
- 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%.
- What material is used for the filament of incandescent lamps? Explain why.
- From the curve given in Fig. 4, determine the efficiency which corresponds to the temperature of 1300o Centigrade.
- What is the object of double carbons in an arc lamp?
- What is meant by mean spherical candle-power?
- What is the function of the heater in the Nernst lamp?
- Describe the Bunsen Photometer.
- How does the lighting of public halls differ from that of residences?
- Why cannot platinum wire be used for the filament of incandescent lamps?&9632;
- In a direct-current arc lamp, which carbon burns away the more rapidly?
- How are arc lamps rated?
- What are the important advantages of the two-wire parallel system of distribution?
- Name and describe the most desirable standard for photometric measurements.
- How many measurements should be taken in the determination of spherical intensity?
- What is meant by flashing? Explain.
- Define emissivity.
- If the voltage of an incandescent lamp be increased 4% above normal, what is the effect on the candle-power, efficiency and light?
- Explain the Cooper-Hewitt lamp, stating the two methods of starting.
- Compare the open and enclosed arc lamps.
- Why is the positive carbon placed above the negative in a direct- current arc lamp?
- Sketch and name the different forms of incandescent lamp filaments.
- Under what conditions can a 3.1-watt incandescent lamp be used ?
- What is the function of the arc lamp mechanism?
- What are the advantages of the three-wire system?
- Why is it necessary to exhaust the bulb of an incandescent lamp?
- At what point in their life should incandescent lamps be replaced ?
- What is the object of a resistance in series with the arc lamp in constant-potential direct-current systems?
- Name the advantages of the Nernst lamp.
3G. What sort of lamps and of what candle-power should be used in residence lighting?
- Give the characteristics of the Cooper-Hewitt lamp.
- What will be the external resistance on a 110 volt constant- potential system, if the load consists of 437 lamps of 16 candle- power?
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