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# Electrical Engineers, Proceedings of the Institution of

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Displaying Results 1 - 25 of 28
• ### Acoustic-surface-wave dispersive delay line

Publication Year: 1969, Page(s):1125 - 1134
Cited by:  Papers (5)
| | PDF (1386 KB)

The requirements for a dispersive delay line, for pulse-compression radar, capable of operating at v.h.f. and microwave frequencies, suggest the use of an acoustic-surface-wave system. The basic structure consists of a thin film supported on a substrate. It is shown how a required delay characteristic can be synthetised by tapering the thickness of the film. Experiments carried out at relatively l... View full abstract»

• ### Feasibility studies of synchronised-oscillator systems for p.c.m. telephone networks

Publication Year: 1969, Page(s):1135 - 1143
Cited by:  Papers (8)
| | PDF (1203 KB)

Two important classes of linear control system for pulse-code-modulated exchange-oscillator synchronisation are described. These are known as single-endedÂ¿ and double-endedÂ¿ systems. This paper extends the knowledge of the stability and steady-state frequency for the single-ended system, and derives the corresponding information for the double-ended system. Both systems have discontinuous phas... View full abstract»

• ### Magnetic reflection of constant-radius annular electron beams

Publication Year: 1969, Page(s):1145 - 1149
| | PDF (493 KB)

The conditions that have to be satisfied by an axially symmetric field, when the scalar-potential distribution on a cylinder coaxial with the field is specified, are determined. It is shown that an infinite number of fields may be found to satisfy these conditions. A method is then given whereby this result may be used to synthetise magnetic fields that would reflect a constant-radius annular elec... View full abstract»

• ### Near fields and antipodal fields in the terrestrial Earthߝionosphere waveguide

Publication Year: 1969, Page(s):1150 - 1158
Cited by:  Papers (1)
| | PDF (1195 KB)

Near fields of a vertical electric dipole are expressed as a series of zonal harmonics, or as a summation of waveguide modes. These representations are compared with dipole fields on a conducting ground plane, and with field calculations, using the method of images or ray theory. The series of zonal harmonics and the mode sum provide nearly identical near fields; their difference characterises the... View full abstract»

• ### Screening: new wave impedance for the transmission-line analogy

Publication Year: 1969, Page(s):1159 - 1164
Cited by:  Papers (4)
| | PDF (576 KB)

New expressions for the wave impedances associated with magnetic-dipole and current-loop sources are derived. It is shown that the transmission-line equations may be used to determine the shielding effectiveness of a plane screen placed between two coaxial coils. When the new expressions for the wave impedance are inserted in the equations, excellent agreement between theory and practice is obtain... View full abstract»

• ### Minimisation of r.m.s. phase error in large reflector antennas

Publication Year: 1969, Page(s):1165 - 1167
| | PDF (460 KB)

A method of minimising the r.m.s. phase error in a large, paraboloidal reflector antenna is presented. The problem involves the search for the axis, the focus and the focal length of the paraboloid which best fit the actual reflector, in the least-square sense. Although standard techniques may be successfully employed, the method presented in this paper is simple, and results can be quickly obtain... View full abstract»

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

Publication Year: 1969
| PDF (186 KB)
• ### P.A.M. graded concentric windings for 2-speed single-phase induction motors

Publication Year: 1969, Page(s):1169 - 1177
Cited by:  Papers (1)
| | PDF (1078 KB)

The principle of pole-amplitude modulation is described in relation to pole-changing concentric windings for single-phase motors. It is shown that satisfactory performance can be achieved at two speeds, using single mainÂ¿ and auxiliaryÂ¿ windings which are similar to those commonly employed in single-speed fractional-horsepower motors. Speed selection is effected by means of a simple switch, an... View full abstract»

• ### Discussion on "Synthetic testing of a.c. circuit breakers. Parts 1 and 2"

Publication Year: 1969
| PDF (206 KB)
• ### Single-phase induction motor with asymmetrical-cage rotor

Publication Year: 1969, Page(s):1179 - 1184
Cited by:  Papers (1)
| | PDF (626 KB)

First Page of the Article
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• ### Water-cooled generator connections

Publication Year: 1969, Page(s):1185 - 1197
| | PDF (2151 KB)

The increase in rating of generating plant in the past two decades has greatly increased the problems of conducting the power away to the distribution system. The conventional arrangement of naturally aircooled busbars has reached such a size that accommodation within the machine foundations is becoming increasingly difficult, and the use of forced cooling is an obvious solution. Forced-air coolin... View full abstract»

• ### Discussion on "Techniques for load prediction in the electricity-supply industry"

Publication Year: 1969, Page(s):1198 - 1200
| PDF (596 KB)
• ### Fault-development control in a.c.-d.c. convertors

Publication Year: 1969, Page(s):1201 - 1208
Cited by:  Papers (5)
| | PDF (1025 KB)

A new principle of protection against convertor faults is proposed, consisting of a direct control of the valve-firing sequence. Upon detection of the faulty condition, the firing/blocking sequence most suitable for the development of the particular type of fault is applied. The results of this investigation show that, to a greater or lesser extent, all types of convertor faults benefit from the u... View full abstract»

• ### Some effects of the frequency dependence of transmission-line parameters

Publication Year: 1969, Page(s):1209 - 1216
Cited by:  Papers (4)
| | PDF (895 KB)

Nonzero earth resistivity leads to line parameters which vary continuously with frequency. Some effects of this variation on transient waveforms are examined. The interaction of the source impedance with the frequency-dependent line impedance is shown to have an effect on the length of line at which the resonant frequency approaches that of the supply. A possible single-phase representation of a 3... View full abstract»

• ### Single-wire railway overhead system

Publication Year: 1969, Page(s):1217 - 1221
| | PDF (575 KB)

A mathematical investigation of the static characteristics of a single-wire railway overhead system is outlined, and a computational method of obtaining the displacements of a mathematical model of the equipment, when excited by the passage of a pantograph, is described. The aims of the paper are limited to those of a preliminary investigation, namely to ascertain whether or not the system is feas... View full abstract»

• ### Optoelectronic control of brushless alternators

Publication Year: 1969, Page(s):1222 - 1223
Cited by:  Papers (2)
| PDF (308 KB)
• ### Cogging torques in induction machines

Publication Year: 1969, Page(s):1223 - 1224
| PDF (161 KB)
• ### Jump-resonance criteria for systems containing double-valued and frequency-dependent nonlinearities

Publication Year: 1969, Page(s):1225 - 1228
Cited by:  Papers (1)
| | PDF (414 KB)

A procedure is developed for evaluating the jump-resonance frequencies for feedback systems containing nonlinearities which have complex and frequency-dependent describing functions. The method permits the determination of the multimodal region on the input amplitude/frequency plane, as well as other information concerning the system behaviour at the jump-resonance point. It is therefore convenien... View full abstract»

• ### Self-optimising sampled-data control system employing power-constraint equalisation

Publication Year: 1969, Page(s):1229 - 1236
| | PDF (979 KB)

In this paper, a sampled-data control system is continuously optimised by a sampled-data self-optimising loop which operates on the controller gain. The action of the optimising loop is to maintain the controller output power at its maximum permissible level. The optimising-loop controller is actuated by the error between the desired system-controller output power and the system-controller output ... View full abstract»

• ### Optimal control of a class of distributed-parameter systems using gradient methods

Publication Year: 1969, Page(s):1237 - 1244
Cited by:  Papers (1)
| | PDF (729 KB)

This paper presents a practical approach to the problem of optimal-boundary-control synthesis in 1-dimensional, linear, stationary, distributed-parameter systems. The optimal-control function is obtained directly from a generalised quadratic performance index, by gradient methods extended to the functional space. Algorithms for two gradient methods, namely, the steepest-descent and the conjugate-g... View full abstract»

• ### Canonical form for the matrices of linear discrete-time systems

Publication Year: 1969, Page(s):1245 - 1252
Cited by:  Papers (2)
| | PDF (928 KB)

Some applications of canonical matrices to linear continuous-time systems are reviewed. A canonical form is proposed for real nonderogatory convergent matrices, such as the A matrices which occur in the description of linear discrete-time dynamical systems by vector-matrix difference equations of the form xk+1 = Axk + Buk. The new canonical form is applied to the generation of particular and gener... View full abstract»

• ### Quantisation-error compensation techniques

Publication Year: 1969, Page(s):1253 - 1256
| | PDF (436 KB)

If a digital computer is operated as an online computational device, amplitude-quantisation errors are incurred when analogue data is fed into the machine. This analogue-digital conversion operation introduces a fundamental accuracy limitation into a control or measurement system which incorporates an online digital computer. The paper investigates the effectiveness of three methods of signal proc... View full abstract»

• ### Dynamic control of a power boiler

Publication Year: 1969, Page(s):1257 - 1268
Cited by:  Papers (4)
| | PDF (1733 KB)

A dynamic model of a 300000lb/h natural-circulation boiler, operating with a stop-valve pressure and temperature of 950lbf/in2 gauge and 496Â°C, respectively, is used to investigate possible alternative methods of boiler control. First, conventional analogue controllers incorporating proportional plus integral action are considered. The controller-gain constants are adjusted by informed trial and ... View full abstract»

• ### Accurate root locus plotting including the effects of pure time delay. Computer-program description

Publication Year: 1969, Page(s):1269 - 1271
Cited by:  Papers (3)
| | PDF (291 KB)

First Page of the Article
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• ### Discussion on 'Development and application of self-optimising control to coal-fired steam-generating plant'

Publication Year: 1969, Page(s):1272 - 1276
| PDF (856 KB)

## Aims & Scope

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

Full Aims & Scope