# Electrical Engineers, Proceedings of the Institution of

## Filter Results

Displaying Results 1 - 25 of 36
• ### Wave-propagation analysis of the monolithic-crystal filter

Publication Year: 1969, Page(s):653 - 660
Cited by:  Papers (12)
| |PDF (880 KB)

The monolithic-crystal filter has two or more pairs of electrodes on the same piezoelectric plate; mechanical-wave propagation in the regions between electrodes takes place in an evanescent mode. A method of analysis, based on solutions to the wave equation, is first developed in general terms and then applied specifically to AT-cut quartz. Boundary conditions are used to determine resonant freque... View full abstract»

• ### Wideband 180Â° hybrid junctions using phase-corrected asymmetric directional couplers

Publication Year: 1969, Page(s):661 - 666
| |PDF (673 KB)

A method is given for the design of 0Â° (180Â°) hybrids in TEM-mode transmission lines, the hybrids having a small phase ripple. They consist of optimum asymmetric 3dB couplers cascaded with microwave allpass phase-equaliser networks. The results, which were obtained by optimising the overall phase characteristic using a computer technique, are given in detailed tabular form, and enable hybrids wi... View full abstract»

• ### Theoretical performance of the overmoded right-angle corner

Publication Year: 1969, Page(s):667 - 678
Cited by:  Papers (2)
| |PDF (1148 KB)

This potentially important component in overmoded waveguide is examined by a diffraction analysis, and by a cruder mirror analysis. A general symmetry relation for the corner is deduced, and the diffraction analysis, but not the mirror analysis, is shown to satisfy it. Nevertheless, they both give similar numerical values for the scattered modes, though the former indicates somewhat larger values.... View full abstract»

• ### Electric-field distribution in the focal region of an offset paraboloid

Publication Year: 1969, Page(s):679 - 684
Cited by:  Papers (13)
| |PDF (591 KB)

The electric field in the vicinity of the focus of a finite offset-paraboloid reflector, illuminated by a linearly polarised plane wave, is investigated. The paper begins with a general formulation of the reflected field calculation procedure for an arbitrary reflecting surface. The formulation is then specialised to apply to an offset paraboloid. Extensive computed data of the field in the focal ... View full abstract»

• ### Statistics of tropospheric radio-refractive-index soundings taken over a 3-year period in the United Kingdom

Publication Year: 1969, Page(s):685 - 690
Cited by:  Papers (1)
| |PDF (660 KB)

The paper discusses the statistical distributions of certain refractive-index parameters which are often used in tropospheric radio-propagation problems. The statistics are derived from three years' results of routine psychrometer soundings made at intervals of 75m, every 6h, to a height of 1200m, by the Meteorological Office at Cardington, Bedfordshire. Parameters discussed are surface refractive... View full abstract»

• ### Video-frequency light modulator having a wide angular aperture

Publication Year: 1969, Page(s):691 - 698
| |PDF (1092 KB)

This paper discusses the 45Â° ycut ADP modulator. An investigation of the propagation of light through the crystal shows that there is an inherent limitation in the angular aperture of the simple 2-crystal modulator. The inclusion of a halfwave plate between the crystals to improve the temperature stability also enables large angular apertures to be achieved, provided the crystals are correctly al... View full abstract»

• ### Small-signal, high-frequency equivalent circuit for the metalߝoxideߝsemiconductor field-effect transistor

Publication Year: 1969, Page(s):699 - 702
Cited by:  Papers (12)
| |PDF (355 KB)

The differential equations describing the small-signal sinusoidal operation of the 'intrinsic' m.o.s.f.e.t. structure are solved using modified Bessel functions of the first kind. Expressions for the small-signal short-circuit admittance parameters are obtained in series form. By retaining appropriate terms in the series, the elements of a convenient equivalent circuit are computed for both the no... View full abstract»

• ### Self-starting performance of astable-transistor-multivibrator circuits

Publication Year: 1969, Page(s):703 - 709
| |PDF (853 KB)

Tests are described which have been carried out to investigate the self-starting performance of the simple saturating transistor-astable-multivibrator circuit under different conditions, on connection of the d.c. supply to the circuit. These tests reveal that failure to start is controlled by several complex interacting factors. In general, high-gain transistors are more prone to failure to start ... View full abstract»

• ### Basic nonuniform transmission lines

Publication Year: 1969, Page(s):710 - 712
Cited by:  Papers (2)
| |PDF (342 KB)

It is shown that for any given nonuniform transmission line (n.u.t.l.) Â¿, (which may be a multilayered RC network or a multiwire transmission line), with a per-unit-length series impedance Z(x) and shunt admittance Y(x), there always exists an electrically equivalent inverse lineÂ¿ Â¿E, for which ZY is constant. Further, two more electrically equivalent lines may be found for which either Z or Y... View full abstract»

• ### Application of linear induction motors to high-speed transport systems

Publication Year: 1969, Page(s):713 - 724
Cited by:  Papers (13)
| |PDF (2031 KB)

The linear motor has been chosen as the method of propulsion for the full-scale prototypes of several high-speed transport systems currently being developed. The paper sets out the problems of the electrical design of such systems, showing its interdependence with the mechanical and thermal designs. Attention is then concentrated on the double-sided flat linear, motor with conducting-sheet seconda... View full abstract»

• ### Transverse edge effect in sheet-rotor induction motors

Publication Year: 1969, Page(s):725 - 731
Cited by:  Papers (38)
| |PDF (831 KB)

A 2-dimensional-field analysis is presented for the problem of the sheet-rotor induction motor with finite width. Account is taken of the redistribution of the air-gap flux under the action of currents which flow in the active portion of the sheet in the direction of motion. The performance is shown to depend on three dimensionless parameters which are functions of the design data and the slip. It... View full abstract»

• ### Effect of parameter changes on the performance of shaded-pole motors

Publication Year: 1969, Page(s):732 - 736
Cited by:  Papers (5)
| |PDF (511 KB)

Using a method of analysis previously published by the authors, computed results are presented of changes of some of the performance characteristics of a shaded-pole motor due to varying its major design features, namely, the number of main-winding turns, the total-pole arc, the shaded-pole arc, the shading-ring conductance, and the resistance and skew of the rotor cage. Such results enable the ch... View full abstract»

• ### Stray losses of polyphase cage-induction motors with particular reference to the condition of imperfect rotor-barߝiron insulation

Publication Year: 1969, Page(s):737 - 751
Cited by:  Papers (24)
| |PDF (1812 KB)

The paper presents an analysis of stray losses in polyphase cage-induction motors, under linear and saturation magnetisation conditions, with particular attention being given to the effects of circumferential currents flowing in the rotor as a consequence of imperfect bar-iron insulation. Such effects are included in a modified equivalent circuit of the motor, and are expressed in terms of factors... View full abstract»

• ### Variable-characteristic synchronous machines

Publication Year: 1969, Page(s):752 - 762
Cited by:  Papers (1)
| |PDF (912 KB)

The paper deals with the operation of a standard cylindrical-rotor synchronous machine with several novel forms of excitation control. It shows how, by using a nonlinear function of load-angle control, the machine can be made to develop characteristics normally associated with a salient-pole machine, and how a very wide range of the effective ratio of direct-axis to quadrature-axis synchronous rea... View full abstract»

• ### Development of an electronically commutated motor with laminated brushes

Publication Year: 1969, Page(s):763 - 768
| |PDF (699 KB)

Recent developments in switching by means of thyristors offer possibilities for commutating motors electronically. The method proposed uses a laminated form of brush, and is applicable to existing motors or d.c. generators. Trial equipment was tested over a wide range of speeds in a d.c. motor, and with high current densities in a 200kW d.c. generator, with promising results. View full abstract»

• ### Generalised treatment on single-phase motors with the aid of a digital computer

Publication Year: 1969, Page(s):769 - 770
| |PDF (257 KB)

First Page of the Article
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• ### Improvement of alternator stability by controlled quadrature excitation

Publication Year: 1969, Page(s):771 - 780
Cited by:  Papers (15)
| |PDF (1175 KB)

Operation of a synchronous generator at leading power factor has been severely limited in the past because of stability considerations. A regulator, acting on a normal direct-axis field winding, can only extend the range of stability when the generator is loaded, and has no effect under unloaded conditions. An additional winding on the quadrature axis, provided with a suitable control, can, howeve... View full abstract»

• ### Importance of winding and permeance harmonics in the prediction of reluctance-motor performance

Publication Year: 1969, Page(s):781 - 787
Cited by:  Papers (2)
| |PDF (586 KB)

Extending earlier analyses by Lawrenson and Gupta on single-speed machines and by Lawrenson, Gupta and Vamaraju on multispeed machines, generalised performance equations for single-and multispeed operation of reluctance machines are given, and their validity is supported by experimental results. The equations are used to investigate the effects of permeance and m.m.f. harmonics on machine performa... View full abstract»

• ### Erratum: Output coefficient of synchronous machines. A new concept

Publication Year: 1969
| |PDF (35 KB)
• ### Surge transfer through transformer-generator units

Publication Year: 1969, Page(s):788 - 800
Cited by:  Papers (4)
| |PDF (1823 KB)

The paper describes a study of the transfer of lightning surge voltages through transformers, between high-voltage overhead transmission-lines and directly connected generators. As such, it covers similar ground to the companion paper by E. L. White, which deals more fully with the theoretical aspects of the subject, and also reports simulated on-site surge tests on three transformer-generator uni... View full abstract»

• ### Thyristor control of a multiload system with d.c. supply

Publication Year: 1969, Page(s):801 - 810
| |PDF (1312 KB)

A thyristor control system has been developed for several loads energised from a common d.c. supply. All load-controlling thyristors are turned off at regular intervals by an interruptor unit interposed between the supply and the loads. Loads can be controlled, either in an on-offÂ¿ mode or using mark/space regulating techniques. Several configurations are considered. One is chosen to control 110... View full abstract»

• ### Bridge rectifiers with double and multiple supply

Publication Year: 1969, Page(s):811 - 821
Cited by:  Papers (1)
| |PDF (896 KB)

The paper presents a new type of bridge rectifier with more than one 3-phase supply, suitable particularly for higher direct voltages. A generalised method of analysis for such multisupply bridges is derived, and detailed characteristics of various double-supply bridge rectifiers are given. View full abstract»

• ### External thermal resistance of two buried cables. Restricted application of superposition

Publication Year: 1969, Page(s):822 - 826
Cited by:  Papers (4)
| |PDF (664 KB)

New formulas are derived for the external thermal resistance of one of two equally loaded identical cables laid direct in the ground at the same depth. The formulas are based on a restricted application of the principle of superposition, and remain valid when the cables are close or touching. Two assumptions made are that the depth of the buried cables is much greater than the cable radius, and th... View full abstract»

• ### Electroheated fluidised beds

Publication Year: 1969, Page(s):827 - 833
Cited by:  Papers (1)
| |PDF (698 KB)

Use of electroheated fluidised beds is a fast-growing branch of electroheating, but this growth has been hampered because the models available hitherto were incomplete, in that they ignored flow and mode dependence and were unnecessarily complicated for the engineer concerned with practical industrial processes. A class of conducting fluidised beds, representing common chemical, metallurgical and ... View full abstract»

• ### Effects of internal discharges on prospective life and overvoltage-withstand behaviour of e.h.v. oil-impregnated paper bushings

Publication Year: 1969, Page(s):834 - 846
| |PDF (1761 KB)

The paper gives the results of an experimental laboratory investigation of model bushings, with the object of predicting the behaviour of full-scale e.h.v. oil-impregnated paper bushings operating at a radial a.c. stress of 3kV r.m.s./mm. One of the aims was to determine whether discharges of up to 5pC in full-scale bushings might damage the insulation during prolonged periods in service, and so r... View full abstract»

## Aims & Scope

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

Full Aims & Scope