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Electrical Engineers, Proceedings of the Institution of

Issue 12 • December 1968

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Displaying Results 1 - 23 of 23
  • Model for a synchronous p.c.m. transmission complex

    Publication Year: 1968, Page(s):1743 - 1748
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (715 KB)

    One of the proposed synchronisation systems for a large-scale p.c.m. transmission and switching complex uses independent oscillators at each station, which are phase-locked to the average phase of all the incoming lines. This paper derives a simple analogue to the system which allows a sufficient stability condition to be stated by inspection. The effect of parameter changes upon the equilibrium f... View full abstract»

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  • Internal structure and parametric representation of equivalent resistive n-port networks

    Publication Year: 1968, Page(s):1749 - 1754
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (742 KB)

    The theory of resistive n-port networks has attracted considerable interest during the last decade. This is due, partly, to the fact that results obtained in analysis and synthesis of resistive networks have been applied to many other engineering problems. The field of applications covers all such systems which can be modelised by nets whose branch characteristics may be expressed by real numbers,... View full abstract»

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  • Experimental tests with orthogonal transmission

    Publication Year: 1968, Page(s):1755 - 1761
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (845 KB)

    Propagation tests indicate that the skywave field strength from a medium-frequency broadcasting transmitter can be reduced by 16dB on paths to the north at midlatitudes in the southern hemisphere, when vertically polarised transmission is replaced by orthogonal transmission. The reduction is observed to vary with time and path bearing, the variation with time being such that, during any one night,... View full abstract»

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  • Application of finite elements to the solution of Helmholtz's equation

    Publication Year: 1968, Page(s):1762 - 1766
    Cited by:  Papers (11)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (501 KB)

    A novel method, that of finite elements, for the solution of Helmholtz's equation is suggested. Various 2- and 3-dimensional problems are solved using this method, and the results are compared with more conventional techniques, particularly the finite-difference method, which it may be regarded to supersede. The ease with which various boundary conditions may be handled is discussed and illustrate... View full abstract»

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  • Equivalent circuit for nonquadrature, tapped-quadrature and shaded-pole single-phase induction motor

    Publication Year: 1968, Page(s):1767 - 1771
    Cited by:  Papers (4)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (507 KB)

    It is shown that the nonquadrature, tapped-quadrature and shaded-pole forms of single-phase induction motor can be equivalent to a conventional quadrature motor having a common line impedance. It follows that a single equivalent circuit can be used to determine the performance of each form of motor, provided that appropriate values are employed for the circuit elements in each case. In consequence... View full abstract»

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  • Travelling waves in induction machines: input impedance and equivalent circuits

    Publication Year: 1968, Page(s):1772 - 1776
    Cited by:  Papers (24)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (709 KB)

    The problem of travelling electromagnetic waves in multiregion induction machines at power frequencies is examined. Using the concept of surface impedance, a method is derived whereby equivalent circuits can be established in a systematic manner. A method of determining levitation force from a knowledge of the equivalent circuit is developed. Calculation of input and output power is simplified usi... View full abstract»

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  • Induction-motor losses due to nonsinusoidal supply waveforms

    Publication Year: 1968, Page(s):1777 - 1782
    Cited by:  Papers (38)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (740 KB)

    The paper presents an analytical and experimental study of the additional losses which occur in induction motors supplied with nonsinusoidal waveforms. Measurements on an inverted induction motor are used to show the importance of losses due to skew-leakage and end-leakage fluxes, and to verify the methods developed for calculating these components. Computed losses are compared with test results o... View full abstract»

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  • Cogging torques in induction machines

    Publication Year: 1968, Page(s):1783 - 1790
    Cited by:  Papers (4)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1111 KB)

    Depending on the choice of design parameters, an induction machine can produce a cogging torque sufficiently high to give rise to locking at standstill. It is noted that the commonly used method of analysis of these torques, involving permeance waves, is strictly incorrect, and its use in conjunction with the `overlap¿ method is inaccurate. The way in which cogging torques arise is discussed in t... View full abstract»

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  • Performance of Lorenz-type medium-frequency inductor alternators on load

    Publication Year: 1968, Page(s):1791 - 1800
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (975 KB)

    Earlier papers have discussed the air-gap flux-density distribution in inductor alternators and have verified the theory by measurement. It is the aim of this paper to show that, with a knowledge of flux-density distribution, it is possible to predict the load performance of these machines from the open-circuit curve¿an easily calculable starting point. First, the measured open-circuit voltages a... View full abstract»

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  • Output coefficient of synchronous machines. A new concept

    Publication Year: 1968, Page(s):1801 - 1807
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (829 KB)

    In the design of synchronous salient-pole generators and motors, current formulas for the output coefficient express this constant in terms either of the apparent power, speed, length of stator core and gap diameter or of the magnetic and electric loading. The paper develops an analysis in which the output coefficient is expressed as a function of the dimensions of the stator core, the magnetic lo... View full abstract»

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  • Simulation of convertor performance under unbalanced conditions

    Publication Year: 1968, Page(s):1809 - 1817
    Cited by:  Papers (4)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1307 KB)

    The paper is devoted to the development of mathematical models for the analysis of the behaviour of h.v.d.c. convertors during unbalanced a.c. faults. A current-source simulation is used for the convertor in either 3-phase or sequence components representation. The analysis using these models can be adapted for digital/analogue simulation. Using the digital approach, results were obtained for syst... View full abstract»

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  • Discussion on 'Computer solution of e.h.v. underground-cable cooling problems'

    Publication Year: 1968, Page(s):1817 - 1820
    IEEE is not the copyright holder of this material | PDF file iconPDF (638 KB)
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  • Nonlinear transformer-winding synthesis for improved surge-voltage distribution

    Publication Year: 1968, Page(s):1821 - 1827
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (745 KB)

    The paper shows that the capacitance and inductance distributions within a power transformer can be so synthetised that an acceptable transient surge-voltage distribution can be obtained without necessarily requiring the reinforcement of end turns. This process can furthermore be carried out without contravening practical requirements, in particular without increasing a given transformer frame siz... View full abstract»

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  • Control-system stability in multiterminal h.v. d.c. systems

    Publication Year: 1968, Page(s):1828 - 1834
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (609 KB)

    A linearised analysis of a multiterminal h.v. d.c. system leads to a stability criterion in a convenient form for assessing the results of changes in controller properties at one terminal. Constant-current, constant-power and constant-extinction-angle control are considered in detail, and the stability of various control configurations is examined. The predictions of the small-signal analysis are ... View full abstract»

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  • Magnetic properties of grain-oriented silicon iron. Part 1: Use of ceramic displacement transducers for the measurement of magnetostriction

    Publication Year: 1968, Page(s):1835 - 1839
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (481 KB)

    One basic problem in the measurement of magnetostriction in laminations is that samples of silicon-iron sheet are rarely perfectly flat when tested. This can sometimes lead to spurious values for the longitudinal magnetostriction, with ceramic displacement transducers. A method has been developed whereby, using three transducers in turn, the true longitudinal component of magnetostrictive motion c... View full abstract»

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  • Magnetic properties of grain-oriented silicon iron. Part 2: Basic experiments on the nature of the anomalous loss using an individual grain

    Publication Year: 1968, Page(s):1840 - 1845
    Cited by:  Papers (4)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (656 KB)

    Measurements of the position of the parallel-bar-domain walls at various points on the magnetising cycle have been made over the frequency range 25¿100 Hz in an individual grain of transformer steel, using the Kerr magneto-optic technique. A single-turn search coil of very thin wire wound around the test grain, through two 0.004 in holes, enabled the flux density to be measured. By plotting the d... View full abstract»

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  • Dielectric loss of poly(4-methyl pentene-1) at cryogenic temperatures

    Publication Year: 1968, Page(s):1846 - 1848
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (357 KB)

    The loss-tangent of aged samples of poly(4-methyl pentene-1) have been measured within the temperature range 2.5¿295° K and frequency range 229Hz¿21.5kHz. These results have been compared with published results made on a new sample of the polymer. The nature of the loss tangent and the number of absorption regions depended on the age of the polymer. The aged samples exhibited absorption regions... View full abstract»

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  • Platinum-based permanent-magnet alloys

    Publication Year: 1968, Page(s):1849 - 1852
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (413 KB)

    Studies of the changes in magnetic properties of PtCo and PtFe consequent on replacing part or whole of the platinum by palladium, rhodium, iridium and ruthenium, and on preparative methods and heat treatments for these alloys, have shown that the pseudobinary alloys do not appear to offer improvements in magnetic properties. By careful heat treatment of PtCo, made by sintering and working or by v... View full abstract»

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  • Evaluation of some aspects of relativity

    Publication Year: 1968, Page(s):1853 - 1856
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (628 KB)

    If the relativity theory is to predict experimental results about the rates of clocks, the time intervals must be defined in such a way that they are capable of measurement. When this is done the confusion which has been associated with the theory is explained. The theory is shown to be self-consistent up to a point, but an error is then made in the course of a `thought experiment¿. The result gi... View full abstract»

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  • Volume dependence of electric strength of polymers

    Publication Year: 1968
    Cited by:  Papers (9)
    IEEE is not the copyright holder of this material | PDF file iconPDF (111 KB)
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  • Application of a computerised alarm-analysis system to a nuclear power station

    Publication Year: 1968, Page(s):1858 - 1864
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (950 KB)

    The paper describes the alarm analysis by digital-computer system which has been installed and is now operating at Oldbury nuclear power station. This is the first such plant in which alarm information has been presented to the operators by c.r.t. displays. The paper also shows how the predicted alarm fault patterns, on which the analysis is based, were prepared for programming. Some details of op... View full abstract»

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  • Dynamic performance of induction motors in control systems

    Publication Year: 1968, Page(s):1865 - 1870
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (548 KB)

    The paper analyses the behaviour of induction motors in control systems in response to sinusoidally varying torque distrurbances by using a 2-coil rotor model. It is found that induction motors exhibit resonance and possibilities of instability in response to torque disturbances, and transient torques substantially greater than the steady-state peak torque of the motor may be generated in the regi... View full abstract»

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  • Design of an accurate sampled-data simulator using field-effect transistors

    Publication Year: 1968, Page(s):1871 - 1877
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (969 KB)

    The paper describes the design of an analogue simulator suitable for sampled-data systems. The basic unit, the zero-order sample and hold, uses field-effect transistors and employs methods which allow a single value of the holding capacitor to be chosen to cover a variation in sample frequencies of 1:6 × 105, consistent with a sample time ts¿ 1 ¿s and a hold/sample ratio not greater than 3 × 1... View full abstract»

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Aims & Scope

The Proceedings of the Institution of Electrical Engineers was published by the IET between 1963 and 1979.

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