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Electrical Engineers, Proceedings of the Institution of

Issue 4 • Date April 1963

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Displaying Results 1 - 25 of 25
  • Flux linkage between two solenoidal tape windings as a factor in the reading of cylindrical thin-film logical elements

    Publication Year: 1963 , Page(s): 631 - 640
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1001 KB)  

    Cylindrical ferromagnetic films can be used as logical elements, and when axially aligned they are energized, and the remanence is sensed, by cylindrical current sheets. The read `1¿ to `0¿ ratio is influenced by the mutual inductance between the sheets. The mutual inductance between two solenoidal tape windings has been measured, the windings being formed around a copper rod because the films are mostly produced by electrodeposition on to a conducting substrate. The experimental results have been compared with the solutions of the magnetic-field diffusion equation, thereby establishing the relative importance of the dimensions and resistivities of the various conductors in the frequency range 0 to about 10 Mc/s. View full abstract»

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  • Non-linear diffusion of minority carriers

    Publication Year: 1963 , Page(s): 641 - 646
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (550 KB)  

    A study of the non-linear diffusion of minority carriers has been carried out. Once the starting terms have been defined, i.e. the diffusion constant depends on carrier concentration according to Webster's formula Dp=Dp0(1+P/P+Nd) an exact first integral is found, from which a study of the influence of bulk recombination on the current gain of a transistor is made. An expression for the base control charge is also found. Finally approximate formulae are derived showing the dependence of carrier concentration on distance. Results are valid for any injection level and distance. Rittner has studied the same problem when the lifetime of minority carriers is infinite. His results are not very different from the linear theory and do not provide a good description at distances larger than the diffusion length. View full abstract»

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  • High-frequency silicon-controlled-rectifier sinusoidal inverter

    Publication Year: 1963 , Page(s): 647 - 652
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (644 KB)  

    In inverter circuits employing switching elements such as silicon controlled rectifiers (s.c.r.) the recovery time of the device normally limits the maximum operating frequency of the circuit. The recovery time allowed by the circuit is invariably limited to some fraction (usually about one-fifth) of one half-cycle. Circuits employing s.c.r.s with 20 ¿s recovery time cannot therefore be used in inverters intended to run above 5kc/s unless this proportion can be increased by some means. The inverter described in the paper generates a sinusoidal waveform and uses the principle of time sharing to enable the circuit quenching time to be extended over several half-cycles.1 It is thus possible to use large s.c.r.s with long recovery times to generate directly very high powers at frequencies up to at least 100 kc/s, and the small diffused type of s.c.r. should be capable of operation at much higher frequencies. A simple inverter delivering 100 W at 50kc/s is described as an illustration of the general principle. View full abstract»

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  • Determination of the electrical characteristics of Hall plates

    Publication Year: 1963 , Page(s): 653 - 659
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (666 KB)  

    The theoretical determination of the electrical behaviour of the Hall plate has hitherto involved difficult computations based on the mathematical technique of conformal transformation. The paper outlines an alternative method of theoretically deriving such electrical characteristics, based on the numerical solution of the finite-difference form of Laplace's equation using a digital computer. The method, while basically simple, is capable of application to Hall plates of any configuration. View full abstract»

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  • Absolute calibration of a class of torque-operated microwave wattmeters incorporating resistive elements

    Publication Year: 1963 , Page(s): 660 - 664
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (554 KB)  

    A general method of calibration suitable for loss-free (or low-loss) torque-operated microwave wattmeters has been developed by the author in a previous paper. The present paper describes an extension of that theory to cover the case of a wattmeter of which a component part is a lossy element in which a fraction of the power to be measured is dissipated. To apply the method, it is necessary that the lossy element be detachable, so that it can be replaced by a movable short-circuit. An example of such an instrument is the microwave analogue of the electrostatic wattmeter, recently proposed by Barlow. The new method of calibration was developed with particular reference to that instrument, though it is capable of somewhat wider application. View full abstract»

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  • Gyromagnetic resonance graphical design data

    Publication Year: 1963 , Page(s): 665 - 670
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (593 KB)  

    A set of graphical solutions of Kittel's equation of gyromagnetic resonance is plotted. The graphs present the d.c. magnetic fields in normalized form as functions of sample shape for commonly used shapes. The curves help in the visualization of the magnetic condition of resonant elements and in the mechanization of the application of Kittel's equation to the design of ferrite microwave components. View full abstract»

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  • Simulation of rational transfer functions with adjustable coefficients

    Publication Year: 1963 , Page(s): 671 - 679
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (817 KB)  

    Design techniques are described for the simulation of quadratic factors of rational transfer functions with independent control of each coefficient. Rational-function approximations, for the simulation of dead time, are considered. Other typical examples are described and include the simulation of the Butterworth, Cheby¿shev and orthonormal functions which have application in self-optimizing control systems. View full abstract»

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  • Distribution of information in stop consonants

    Publication Year: 1963 , Page(s): 680 - 689
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1188 KB)  

    A representative sample of stop-consonant sounds was recorded on magnetic tape. These were then cut out and spliced close together; they were played back and their oscillograms recorded with a camera of the continuously motor-driven type. On this film the required parts of the sounds, their gap, burst, transition, etc., can be located. By simple proportion the corresponding regions are marked off on the original recording tape. Each one of these parts is then cut out in turn and the part from another sound inserted in its place. A large number of these resulting sounds are collected on one long tape. The final recording is then played to an appropriate audience who judge the sounds and record what they hear. Their responses are submitted to mathematical analysis, which gives an indication of how the information is distributed in the stop-consonant sounds. In addition, evidence is obtained and ideas are advanced of the manner in which stop consonants are recognized. These have important implications for devices intended to recognize stop consonants efficiently. View full abstract»

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  • Discussion on "Unstable electron flow in a diode"

    Publication Year: 1963 , Page(s): 689 - 690
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  • Relaxation Oscillator circuits using complementary transistors

    Publication Year: 1963 , Page(s): 690 - 692
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  • Sums of probability distributions expressed in decibel steps

    Publication Year: 1963 , Page(s): 692 - 694
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (317 KB)  

    First Page of the Article
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  • Turbo-type generators. Review of progress

    Publication Year: 1963 , Page(s): 695 - 702
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1325 KB)  

    First Page of the Article
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  • General-purpose turbo-alternator model

    Publication Year: 1963 , Page(s): 703 - 713
    Cited by:  Papers (36)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1219 KB)  

    The present trends in power-system design cause a continual reduction of the stability margins of generators connected to the British Grid system. This is due, primarily, to the changing characteristics of the turbo-generators, and, for this reason, the need has arisen for an accurate generator model for use in stability studies of future systems. The paper describes the development of a mathematical model which includes many of the features normally neglected in conventional network-analyser and digital-computer studies. The model includes mechanical and electrical damping, flux variations, iron saturation and saliency, and it also permits the inclusion of voltage-regulator and governor action. By solving the equations on an analogue computer, the accuracy of the mathematical model is assessed by comparison with test results obtained on a 30 MW turbo-generator. Recommendations are then made for improving the model. View full abstract»

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  • Rectifiers and rectifier applications. A review of progress

    Publication Year: 1963 , Page(s): 714 - 738
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (4104 KB)  

    Very great changes have taken place recently in connection with rectifiers and their applications, and this seems to be a suitable moment to survey the state of world developments and the trends. The rectifiers considered here are limited to those of substantial power, for the ordinary industrial and traction applications. They therefore mainly comprise (i) mercury-arc convertors for wide-range grid control, and (ii) silicon rectifiers (with the thyristor growing in use), for electrochemical service, for 50c/s railway traction, and for nearly all other purposes. Among the subjects reviewed are the latest ideas on mercury-arc convertors, the methods of applying these to reversible drives, and the effects produced on the a.c. system. Rectifiers are now being increasingly used for field excitation of rotating machines; and improvements in variable-speed a.c. motors may be expected; The construction of semiconductor-diode cells is reviewed, as also are the methods of over-current and over-voltage protection. In the latter connection the `controlled avalanche rectifier¿ represents a promising new advance. Another very recent feature has been the combination of the transformer and rectifier as a single unit. The specially important field of the use of semiconductor rectifiers for 50c/s a.c. traction is briefly surveyed. Finally some account is given of the construction and characteristics of the thyristor, and of the circuit considerations that arise in its use. View full abstract»

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  • New transductor-type d.c. transformer particularly applicable to h.v. d.c. systems

    Publication Year: 1963 , Page(s): 739 - 750
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1349 KB)  

    The paper reviews briefly the transductor-type d.c. transformers which are at present in use, including the type using two sets of cores and 90° phase displacement between their auxiliary a.c. supplies. It is shown in the paper that a transductor-type d.c. transformer can be constructed without core duplication, but which nevertheless avoids the production of commutation pulses or notches in its output, this being necessary for the successful operation of fast protective and control equipment in h.v. d.c. systems. Notchless operation is attained by the use of auxiliary circuits associated with the core windings of the measuring transductor. Furthermore, by providing a simple additional circuit, a high degree of transformation accuracy can be obtained throughout the range of measurement. The design parameters of the new d.c. transformer are discussed, together with the particular design of one for experimental purposes. The performance of this transformer is given in the paper, by comparison with a conventional d.c. current transformer constructed on the same size and type of core and with the same winding specification. It is shown that, for the same transient performance, the new d.c. transformer is always more economical than those of conventional pattern; this is true even when it is necessary to include a switching arrangement to provide for d.c. measurement of either polarity. View full abstract»

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  • Effects of tensile stress on the magnetic properties of grain-oriented silicon-iron laminations

    Publication Year: 1963 , Page(s): 751 - 757
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (845 KB)  

    The paper presents the results of an investigation into the effects of tensile stresses on grain-oriented 3 1/4% silicon-iron laminations. Some results are also given for non-oriented 4% silicon iron and for dynamo iron. It is found that tension in the rolling direction of grain-oriented material produces a sharp fall in permeability and an increase of hysteresis loss. However, for a direction at 90° to the rolling direction, tensile stress up to an optimum value of about 1000 lbf/in2 produces a substantial increase of permeability and decrease of loss. It is inferred that the grain-oriented material in its initial state has a residual tensile strain of about 55 × 10¿6 in the rolling direction and a residual compressive strain of about 33 × 10¿6 at 90° to the rolling direction. Ferromagnetic domain patterns have been examined under various conditions of magnetization and tensile stress. The results seem to show that the observable surface patterns are not representative of the internal-domain vector distributions. View full abstract»

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  • Testing of mechanical joints in aluminium conductors for insulated cables

    Publication Year: 1963 , Page(s): 758 - 772
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1843 KB)  

    The increasing use of aluminium conductors in insulated cables has created a need for a standardized testing procedure for the evaluation of joints in the conductors. The paper proposes electrical and mechanical evaluation tests which can be used as a basis for discussion preparatory to the formulation of a test specification. The tests are based on theoretical studies and practical experience relating to the mechanism of current transfer through an aluminium contact interface and of the thermo-mechanical stresses set up in the cores of insulated cables. For the electrical tests it is proposed that the joints should be subjected to 2000 load cycles at defined currents based on the maximum current loading likely to be experienced in service, followed by 12 short-circuit impulses of amplitude and duration dictated by the thermal limitations and bursting strength of the cables. It is recommended that a joint should be considered satisfactory if, at the end of the electrical tests, its resistance does not exceed 150% of the equivalent conductor resistance. In the mechanical test it is required that the joint should be capable of withstanding a tensile stress equal to 50% of the ultimate tensile stress of the associated conductor. View full abstract»

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  • North-Western Centre: Chairman's address. Some contributions of electrical engineering to machine-tool design

    Publication Year: 1963 , Page(s): 772 - 773
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (311 KB)  

    First Page of the Article
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  • West Wales (Swansea) Sub-Centre: Chairman's address. Productivity and the part played by electricity

    Publication Year: 1963
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    First Page of the Article
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  • Mathematics as an educational discipline for the engineer

    Publication Year: 1963 , Page(s): 775 - 784
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1630 KB)  

    The utilitarian relationship between mathematics and engineering is explored. The difficulties of mathematical model-building are discussed, and mathematical models are compared with physical models and analogues. The role of the computer (both analogue and digital) is examined. It is suggested that the usual utilitarian view of mathematics, as a tool for use by the engineer, is dangerously misleading, because it can distort the teaching of the subject to engineering students. It is shown that those aspects of mathematics (its tendency to abstraction, generalization and unification) which make the subject difficult to study are in fact of great practical importance to the engineer, particularly in connection with the creative processes of design. Mathematics, as a system of logical thought, has a greater affinity with engineering than is commonly admitted. As a vehicle of education it offers much as part of a preparation for a career in engineering. View full abstract»

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  • Large-scale thermionic power generation from fossil fuels

    Publication Year: 1963 , Page(s): 785 - 792
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (963 KB)  

    A theoretical analysis is made of the use of thermionic diode convertors in electrical power generation from fossil fuels. It is shown that the best way to use such a diode is as a `thermodynamic topper¿: heat rejected from the diode stage is used in conjunction with a conventional steam generator. Various possible diode schemes are discussed: a diode having a caesium-on-tungsten cathode operating at about 1150°C shows most promise and should lead to an increase in overall efficiency from about 40% for the steam cycle to about 46% for the combined cycle. View full abstract»

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  • The vacuum switch. Part 1: Properties of the vacuum arc

    Publication Year: 1963 , Page(s): 793 - 802
    Cited by:  Papers (42)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1382 KB)  

    In any study of switching devices, an understanding of the current conduction processes in the steady or quasi-steady state must precede the investigation of the transient phenomena during the change from the conducting to the insulating state. The paper describes the results of an investigation into the nature of the arcs which are formed when the contacts of a vacuum switch separate. In many respects the vacuum arc is the simplest of all the high-current gas discharges, since there exists no ambient atmosphere to complicate the arcing processes, but this simplicity is only relative, and many assumptions have had to be made to enable a quantitative picture to be built up. The vacuum arc appears to have two very different states; in one, which seems to be the normal condition at currents below about 104A with copper electrodes, the arc is totally unlike high-pressure arcs, and burns as a set of completely separate arcs electrically in parallel. In the other states the arc much more nearly resembles high-pressure arcs. Most of the work described deals with the vacuum arc in the first state, and the density of neutral atoms, ions and electrons in the discharge is calculated as a function of current and position. The influence of the properties of the electrode materials on the arcing voltage and the stability of the arc is described, and the energy balance of the arc is computed. The data from the paper are used in a companion paper to investigate theoretically arc-extinction processes. View full abstract»

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  • The vacuum switch. Part 2: Extinction of an a.c. vacuum arc

    Publication Year: 1963 , Page(s): 803 - 811
    Cited by:  Papers (20)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1160 KB)  

    The paper, using as a basis data already described, analyses the process of arc extinction at current zero in vacuum switches. The interruption of direct current is not considered, since it is possible over only a limited range of current. It is shown that there are three sources of neutral atoms and ions in `ideal¿ vacuum switches, and equations are developed describing the rates of fall of metal-vapour and ion densities between the contacts, and also the form of the post-zero current under the influence of a given restriking voltage. These results are used to predict the order of magnitude of the interrupting ability of a vacuum switch in terms of current, rate of fall of current and rate of rise of restriking voltage. While technical difficulties related to vacuum processing have prevented the full potentialities of the `ideal¿ vacuum switch from being realized, the experimental results obtained suggest that the theory is basically correct in its prediction that the vacuum switch has, at least on a basis of commutating factor, an interrupting ability very much greater than that of any switch employing high-pressure gas discharges. View full abstract»

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  • Analogue investigation of the stability of a graphite power reactor

    Publication Year: 1963 , Page(s): 812 - 820
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1068 KB)  

    The paper describes the causes and nature of instabilities in a graphite power reactor. The scientific investigation of these instabilities is of importance in the design of control systems of nuclear reactors. In the present approach a model of the reactor is chosen that is simple enough to be simulated on a laboratory analogue but includes the essential features of the problem. That the results and conclusions from the smaller system are to a large extent valid for practical cases seems to be borne out by earlier investigators. The stability of a cylindrical reactor, divided into two active regions, has been studied, first with one control rod for each region and later with just a single regulating control rod in the reactor. Each region is simulated as a point reactor coupled to the other region by neutron diffusion. The error signal for the control system is obtained from the change in mean fuel temperature. No dead bands or saturation are provided in the control system. For stable operation of a reactor the lower and upper limits for the controller gain and the nature of the oscillations at these boundaries are investigated. With one control rod, spatial oscillations of power are studied. The effects of variation of moderator temperature coefficient, the equilibrium flux level, and the location of the control rod have been examined. With the help of simplifying assumptions, certain of the above cases have been investigated analytically and compared with the computer results. View full abstract»

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  • Discussion on ¿Choosing transformer ratio-arm bridges¿

    Publication Year: 1963 , Page(s): 820 - 822
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Aims & Scope

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

Full Aims & Scope