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Electrical Engineers, Proceedings of the Institution of

Issue 11 • Date November 1968

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Displaying Results 1 - 25 of 28
  • Shot noise in microwave parametric amplifiers using gallium-arsenide varactors

    Publication Year: 1968 , Page(s): 1587 - 1591
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (533 KB)  

    Measurements of forward-current shot noise in a 4GHz parametric amplifier using a gallium-arsenide varactor are compared with simple theory. Good agreement is obtained for low diode currents (a few microamperes) and low pump levels (or low input/output impedances), but at higher currents or higher pump levels an additional noise source must be included, thought to be due to significant current fro... View full abstract»

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  • Design for a full multiplier

    Publication Year: 1968 , Page(s): 1592 - 1594
    Cited by:  Papers (4)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (233 KB)  

    A cellular array is described which has the property of multiplying two binary numbers, and also of adding either one or two other numbers. The array can be extended to any number of bits. It is proposed that this array might be considered as a full multiplier, analogous to a full adder. Some applications of the array are mentioned. These include the synthesis of a quadratic equation, extracting a... View full abstract»

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  • Further evidence of v.h.f. propagation by successive reflections from an elevated layer in the troposphere

    Publication Year: 1968 , Page(s): 1595 - 1596
    Cited by:  Papers (1)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (302 KB)  

    The paper gives further experimental evidence to support a recent proposal that propagation by double reflection from an elevated layer may be a significant mechanism in v.h.f. transhorizon propagation. This evidence results from a study of the relationship between field strength over a 320km v.h.f. path and height of tropospheric layers determined from soundings made near the path centre. View full abstract»

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  • Dynamic tracking filter as a low-threshold demodulator in f.m. f.d.m. satellite systems

    Publication Year: 1968 , Page(s): 1597 - 1606
    Cited by:  Papers (4)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (1138 KB)  

    The paper provides an analysis of the dynamic tracking filter and compares its capability as a low-threshold demodulator with that of the frequency-feedback demodulator. Crossreference is made to the analysis given in a companion paper in order to show the similarities that exist in the equations governing the threshold extension offered by the two forms of low-threshold receiver. Theoretical curv... View full abstract»

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  • Frequency-feedback receiver as a low-threshold demodulator in f.m. f.d.m. satellite systems

    Publication Year: 1968 , Page(s): 1607 - 1618
    Cited by:  Papers (5)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (1810 KB)  

    With application to satellite communication, a concurrent investigation of the threshold extension to be expected in f.m. f.d.m. operation from the frequency feedback demodulator (f.m.f.b.) and the dynamic tracking filter (d.t.f.) has revealed a close similarity, both algebraically in the expressions governing a performance assessment and quantitatively in the predicted threshold extensions. This ... View full abstract»

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  • Unbalanced magnetic pull in a 6-pole induction motor

    Publication Year: 1968 , Page(s): 1619 - 1627
    Cited by:  Papers (11)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (1090 KB)  

    A 6-pole 10kW induction motor has been specially constructed for a comprehensive series of steady-state and transient measurements of the magnitude of unbalanced magnetic pull resulting from an eccentric air gap. These measurements have shown that unbalanced magnetic pull is critically dependent on Saturation of the magnetic circuit, and that the magnitude in the cage-rotor motor is much less than... View full abstract»

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  • Self excitation of a variable-speed constant-frequency machine

    Publication Year: 1968 , Page(s): 1628 - 1632
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (511 KB)  

    Consider a machine having a 3-phase stator and a wound rotor with commutator and brushes; the brushes rotate at a constant speed. The rotor is driven at a variable speed and fed from the stator through a transformer and a rectifier. This machine, thus excited through the rotor by a direct voltage, produces an alternating stator voltage of constant frequency which is independent of the rotor speed.... View full abstract»

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  • Acoustic noise and vibration of rotating electric machines

    Publication Year: 1968 , Page(s): 1633 - 1640
    Cited by:  Papers (18)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (1565 KB)  

    In recent years, with the growing public awareness of acoustic noise and current work towards International and British Standards concerned with noise from rotating electric machines, work on rotating-machine noise has progressed, from attempts at a qualitative explanation of the more obvious components of machine noise, towards the prediction of the complete acoustic spectrum from the design data... View full abstract»

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  • Close-ratio phase-modulated change-pole machines with improved winding balance

    Publication Year: 1968 , Page(s): 1641 - 1648
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (1088 KB)  

    The windings are divided initially into short segments which are balanced by the distribution of the phase-band lengths on a first pole number. Balance for the second pole number is then achieved by interleaving at least two of these segments. The material is supported by some practical tests on both 3- and 2-phase versions of the windings; the 3-phase experimental machine is compared with a singl... View full abstract»

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  • Commutation phenomena in electrical machines. Part 2: Further experiments in flashover

    Publication Year: 1968 , Page(s): 1649 - 1653
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (749 KB)  

    In an earlier paper, it was established that a major mechanism of flashover involved the generation of a series of intersegmental arcs, and further relevant work has been carried out on the properties and characteristics of such arcs and on means by which they may be extinguished. The dependence of the flashover voltage (per gap) on gap width, the velocity of sliding and the brush grade have been ... View full abstract»

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  • Discussion on "Magnetic equivalent circuits for electrical machines"

    Publication Year: 1968 , Page(s): 1653 - 1654
    Save to Project icon | PDF file iconPDF (317 KB)  
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  • Brushless and self-excited 3-phase synchronous machine

    Publication Year: 1968 , Page(s): 1655 - 1660
    Cited by:  Papers (7)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (809 KB)  

    The paper describes a brushless and self-excited synchronous machine, which uses current compounding in auxiliary stator and rotor windings to produce an excitation current which increases as the load current is increased. With the machine used as an isolated alternator, the effect is sensitive to the power factor of the load, and the increase in excitation current is greater as the load becomes m... View full abstract»

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  • Consideration of the effect of pollution on the potential distribution of insulator systems

    Publication Year: 1968 , Page(s): 1661 - 1666
    Cited by:  Papers (10)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (657 KB)  

    Two methods are outlined for the determination of the effects of a surface pollution film on the potential distribution of insulator systems. One method involves a suitably modified electrolytic tank, and the other is by numerical methods using a digital computer. Examples of both methods are given. View full abstract»

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  • Switching-impulse flashover of air gaps and insulators in an artificially polluted atmosphere

    Publication Year: 1968 , Page(s): 1667 - 1671
    Cited by:  Papers (9)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (716 KB)  

    Rod-rod and rod-plane gaps and a selection of insulators, mostly of dimensions relevant to 110¿132kV systems, have been subjected to switching impulses in artificial pollution. It has been shown that the flashover voltages of the gaps were little affected by the presence of fogs, either of water or of 120g/l salt solution. Substantial reductions, increasing with fog salinity, were found in the fl... View full abstract»

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  • Discussion on "Land and sea transportation of very heavy power-station equipment"

    Publication Year: 1968 , Page(s): 1671 - 1676
    Save to Project icon | PDF file iconPDF (986 KB)  
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  • New 3-phase invertor circuit

    Publication Year: 1968 , Page(s): 1677 - 1683
    Cited by:  Papers (2)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (920 KB)  

    A 3-phase variable-frequency invertor is described. It is capable of controlling the output voltages by an on-off method. The commutation circuit is simple, and is so arranged that the invertor output voltages are independent of the load conditions. The triggering circuit and a protection scheme are also described. The overall efficiency of the invertor is of the order of 90% View full abstract»

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  • Discussion on "Logic behaviour of h.v. d.c. convertors during normal and abnormal conditions" and "Direct digital protection of h.v. d.c. convertors"

    Publication Year: 1968 , Page(s): 1683 - 1684
    Save to Project icon | PDF file iconPDF (354 KB)  
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  • Behaviour of multiterminal a.c.-d.c. interconnections with series-connected stations

    Publication Year: 1968 , Page(s): 1685 - 1692
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (812 KB)  

    All the existing h.v. d.c. schemes are varieties of point-to-point interconnection between two a.c. systems. However, multiterminal interconnections are being proposed and considered, together with general problems of a.c.¿d.c. multiterminal schemes. In this paper, the behaviour of series d.c. links is investigated as regards various types of convertor control and these are discussed and analysed... View full abstract»

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  • D.C. power control for aluminium and electrolytic loads

    Publication Year: 1968 , Page(s): 1693 - 1704
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (1144 KB)  

    The paper discusses critically the control of large d.c. power blocks, often exceeding 100 MW in one unit. Only power supply from silicon rectifiers is considered, since all other power supplies are now obsolete and many existing installations using mercury arc, mechanical rectifiers or machines are likely to change to silicon in the future. The large aluminium line is taken as an example of a dif... View full abstract»

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  • Slip-energy-recovery schemes and the use of pole-change windings

    Publication Year: 1968
    Save to Project icon | PDF file iconPDF (143 KB)  
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  • Slot-shape considerations in electrical machinery

    Publication Year: 1968 , Page(s): 1705 - 1706
    Save to Project icon | PDF file iconPDF (242 KB)  
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  • Initiation of dry bands on polluted insulation

    Publication Year: 1968 , Page(s): 1707 - 1712
    Cited by:  Papers (9)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (704 KB)  

    The loss of moisture and the initiation of dry-band formation on wet contaminated insulation has been studied by measuring the insulation resistance of the contaminated specimen as a function of the degree of contamination, relative humidity, applied voltage and time. Drying of the wet contamination consistently occurred when the power dissipated by the surface leakage currents became sufficient t... View full abstract»

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  • Stress control for sphere-sphere and sphere-plane electrode configurations

    Publication Year: 1968 , Page(s): 1713 - 1716
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (518 KB)  

    The highest potential gradient between a sphere and plane has been calculated by the method of images for various gap-length/sphere-diameter ratios. It is shown that, if the distance between the plane and the most distant point on the sphere is fixed at S, while the sphere diameter is allowed to vary, the highest stress on the sphere surface has the minimum attainable value of 5 16/S times the vol... View full abstract»

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  • Constriction resistance of a circular cylinder

    Publication Year: 1968 , Page(s): 1717 - 1720
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (445 KB)  

    An approximate method is used to calculate the resistance of a circular cylinder with current entering by a concentric circular electrode in one plane face and leaving by the other. Evidence is given suggesting that the values found are highly accurate. The resistance of any cylinder with a step in the radius can be deduced. The results are important in electric-contact theory; the method may be g... View full abstract»

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  • Use of induction mechanism of kilowatt-hour meters for torque measurements

    Publication Year: 1968 , Page(s): 1721 - 1725
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (776 KB)  

    The paper analyses the properties of the induction mechanism of a kilowatt-hour meter as a source of the standard torque compared with the tested torque in a state of stable equilibrium. Theoretical considerations are used to define the limits of applicability of the torque-comparing method and the conditions required for the minimisation of error. The ambient temperature and the nominal frequency... 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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