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Proceedings of the IEE - Part A: Power Engineering

Volume 103, Issue 9, June 1956

Volumes & issues:

Volume 103, Issue 9

June 1956

Scottish Centre: Chairman's address: Straw for the bricks
Highland water power—the developments of the North of Scotland Hydro-Electric Board
  • Author(s): T. Lawrie
  • Source: Proceedings of the IEE - Part A: Power Engineering, Volume 103, Issue 9, p. 212 –228
  • DOI:  10.1049/pi-a.1956.0085
  • Type: Article
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  • p. 212 –228 (17)
    With hydro-electric schemes in the Highlands, amenity and the preservation of salmon fisheries are of great importance. Fish passes and hatcheries have been built and water falls have been opened.There is a dam of pre-stressed concrete and the use of wet ground blast-furnace slag cement in a large gravity dam is a promising development.Over 100 miles of tunnel have been driven and work is in hand on about a further 30 miles.The largest individual water-turbine output is 40 MW and the highest head of water employed is 1 362 ft.For the year 1955–56, the hydro-electric plant capacity is about 634 MW and the annual output about 1 620 million kWh; the coal equivalent of this output is about 960000 tons, or over a fortnight's production of the Scottish coal pits. The 1955–56 output of electricity is likely to be doubled in the ensuing ten years.In 1948, one-half of the total population of the supply area, including 93% of the farms and 99% of the crofts, were without electricity supply mains. A series of comprehensive distribution schemes are being carried out and half the farms and crofts and seven-eighths of the population are now supplied.There is scope for developing 2000 MW of pumped storage in the Highlands between, say, 1961 and 1975, and developments in the remoter future could be much greater.
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Electric traction. A review of progress
Switchgear. A review of progress
  • Author(s): C.H. Flurscheim
  • Source: Proceedings of the IEE - Part A: Power Engineering, Volume 103, Issue 9, p. 239 –262
  • DOI:  10.1049/pi-a.1956.0087
  • Type: Article
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  • p. 239 –262 (24)
    In British switchgear, development during the period under review has been directed mainly towards the improvement of interrupting performance, measured by reliability and speed of interruption of short-circuits, and by the prevention of over-voltages when disconnecting open-ended lines or small reactive currents. It has also been directed towards reducing the size and cost of switchgear and the buildings in which indoor gear is mounted.The techniques of oil, air-break and air-blast interruption, and of multi-break design, with various forms of voltage division, have all been exploited to assist in achieving these aims. There is now little room for further reduction in the minimum size of switchgear for a given voltage, but the MVA rating for the smallest frames, already doubled in this period, will no doubt continue to increase in the future.The upper limit of MVA has increased seven times in the period under review, and there are no obvious limitations to further progress; it is to be expected that the MVA rating available in circuit-breakers of British design will continue to exceed those required on contemporary networks.
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A new meter for the kilovolt-ampere-demand charge
  • Author(s): P. Baxter
  • Source: Proceedings of the IEE - Part A: Power Engineering, Volume 103, Issue 9, p. 263 –270
  • DOI:  10.1049/pi-a.1956.0088
  • Type: Article
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  • p. 263 –270 (8)
    The paper states that the introduction of an electricity tariff based in part upon a maximum apparent-power demand (VA m.d.), creates the need for a meter to measure apparent energy in a manner fair and just to all concerned. It gives two definitions for 3-phase apparent power and selects one as the more suitable basis for assessment of a maximum-demand charge.A brief description is given of a Merz demand mechanism, which registers maximum demand (m.d.) from integrations made over definite time intervals. Reference is made to the difficulties of integrating 3-phase apparent energy (VAh) and these difficulties are held to be primarily responsible for the introduction of alternative methods of m.d. charging. Some of the alternative methods are briefly compared with that of the maximum-apparent-power-demand charge, colloquially known as the kVA charge, in order to explain why so many attempts have been made to produce a true 3-phase apparent-energy meter. The paper recognizes that some very ingenious meters have already been designed but suggests that none is entirely satisfactory for industrial applications. It shows how recent developments have made possible the introduction of a new type of apparent-energy meter based on an entirely new principle.A description is given of a new type of volt-ampere indicating instrument, and this provides an introduction to a treatise on the new apparent-energy meter, whose main components are a dry plate rectifier, a transductor and an induction-type integrating meter.A bibliography is included to indicate the background of knowledge and opinions which influenced the development of the meter.Appendices deal with the interpretations of 3-phase volt-amperes, the voltage representation of a 3-phase system, and—with the aid of oscillographs—describe the operation of the meter components.
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Age and the incidence of fires in electrical installations
  • Author(s): L. Gosland
  • Source: Proceedings of the IEE - Part A: Power Engineering, Volume 103, Issue 9, p. 271 –284
  • DOI:  10.1049/pi-a.1956.0089
  • Type: Article
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  • p. 271 –284 (14)
    The paper reviews data on the occurrence of fires due to defects in fixed electrical installations amongst a population of about 2.5 million consumers over the years 1951–53 inclusive. The correlation between age of installation and the incidence of fires is examined, and it is shown that for installations more than fifteen years old the incidence of fires is roughly proportional to the age of installation. There is no clear indication of any maximum safe life. Installations less than 15 years old are considered as a separate class, being subject to innovations in housing construction and installation practice. Incomplete data on the types of equipment revealed as defective and on the nature of the defects are reviewed. There is no clear indication that any one type of equipment is particularly subject to the effects of age. The most frequent primary cause of fire is defective wiring, and the most frequent secondary cause fortuitous contact between wiring or earth-continuity conductors and composition gas-pipes. Apart from the latter, there seems no single type of defect the elimination of which could lead to outstanding reduction in the incidence of fires.
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The theory and characteristics of the 3:1 pole-changing induction motor
  • Author(s): T.H. Barton ; O.I. Butler ; H. Sterling
  • Source: Proceedings of the IEE - Part A: Power Engineering, Volume 103, Issue 9, p. 285 –294
  • DOI:  10.1049/pi-a.1956.0090
  • Type: Article
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  • p. 285 –294 (10)
    It is shown that the primary winding of a 3-phase induction motor, having p poles, say, may be reconnected to constitute a 3p-pole winding of two or three symmetrical phase windings, the latter being little known and the former being a new type of pole-changing connection with considerable practical possibilities. Thus, a synchronous speed of one-third the normal value is obtained. It is noted that reconnection as an np-pole winding is possible, where n is any odd integer.It is shown also that the performance characteristics of the motor for the 3p-pole connection can be deduced satisfactorily from the design data of the machine, and that the single machine can be designed to provide characteristics which are comparable with those provided by two separate single-speed machines of standard design.Also—for the first time so far as the authors are aware—an attempt is made to predict the performance of an induction motor from design data when the performance is appreciably affected by the presence of pronounced space harmonics of m.m.f. A satisfactory prediction is made possible only when the parameters include the “skew leakage reactance” component, which appears to have been ignored in the published work of this country. It is an important component of the unsaturated leakage reactance in the case of the harmonics of space m.m.f., and an important component also in the case of the fundamental space m.m.f. of a squirrel-cage induction motor having a full-pitch primary winding, and the customary degree of skew of the rotor bars.
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Applications of the 3:1 pole-changing motor
  • Author(s): T.H. Barton ; O.I. Butler ; H. Sterling
  • Source: Proceedings of the IEE - Part A: Power Engineering, Volume 103, Issue 9, p. 295 –305
  • DOI:  10.1049/pi-a.1956.0091
  • Type: Article
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  • p. 295 –305 (11)
    Besides the obvious application of providing two separate and economical running speeds, the application of the 3:1 pole-changing motor to obtain controlled starting, stopping and reversing of industrial drives is considered in some detail. For the latter types of drive, an investigation is made of the energy loss involved, and a comparison with other methods of control is made.It is shown that various asymmetrical connections of the primary winding for the larger pole-number can provide useful characteristics, for both squirrel-cage and slip-ring machines, and, in general, a 2-phase connection of the primary winding for the larger pole-number is likely to be more satisfactory than a 3-phase connection.
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The development of a new 3:1 pole-changing motor
  • Author(s): G.H. Rawcliffe  and  B.V. Jayawant
  • Source: Proceedings of the IEE - Part A: Power Engineering, Volume 103, Issue 9, p. 306 –316
  • DOI:  10.1049/pi-a.1956.0092
  • Type: Article
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  • p. 306 –316 (11)
    The paper describes the development of a new 3:1 pole-changing induction motor with one 3-phase winding only, in which the performance and rating of a given machine frame for each speed are in all respects nearly equal to the best values that could be obtained from the same frame if it were wound in a normal manner for that speed only. The comparison is equally favourable both for torque ratings and for continuous horse-power ratings, and the machine is free from the crawling torques common in pole-changing motors. The number of control leads (eleven) is not unduly large, and the switch controller required is relatively simple.A simple pole-changing winding which gives a high performance for a 2 : 1 speed ratio is well known and widely used, and it seems probable that the development of a winding giving even better performance for a 3 : 1 speed ratio will find many applications, once its existence is generally known. It is believed that this is the first time a satisfactory winding of this type has been devised, although several comparable but unsatisfactory variants have previously been proposed.
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Discussion on “The theory and characteristics of the 3:1 pole-changing induction motor”, “Applications of the 3:1 pole-changing motor” and “The development of a new 3:1 pole-changing motor” before the Utilization Section, 16th February, 1956
The authors' replies to the discussion on “The theory and characteristics of the 3:1 pole-changing induction motor”, “Applications of the 3:1 pole-changing motor” and “The development of a new 3:1 pole-changing motor”
Discussion on “The application of symmetrical components to the measurement of phase difference in single-phase circuits” before the Western Centre, at Bristol, 12th March, 1956
Power station auxiliary plant
Discussion on “Aluminium-sheathed cables”
Discussion on “A criterion of distribution costs” before the North-Eastern Centre, at Newcastle upon Tyne, 9th January, 1956
Discussion on “Proving the performance of circuit-breakers, with particular reference to those of large breaking capacity” and “A new testing station for high-power circuit-breakers”

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