摘要:

Possibilities of electromagnetic separation of the metallic components of spent nuclear reactor fuel elements, according to the materials from which they are made, are investigated. This has advantages in the reprocessing and disposal cycle of fuel management. A design study for a prototype separator, involving no moving parts, is described, and practical problems involved in handling hazardous materials considered.

DOI:10.1049/ip-b.1980.0036

出版商:IEE    

年代:1980

数据来源: IET

摘要:

A method is described to predict the steady-state core loss of, and the flux penetration into, a steel plate, including both hysteresis and eddy-current effects. The family of hysteresis loops obtained with a ferromagnetic material at different levels of magnetisation is represented by a simulation technique, previously described, which requires a set of three nonlinear characteristics only. By using a multilayer approach, the profiles of flux density and magnetising force in the plate are computed. Good agreement was obtained between measured and predicted values of loss and the fundamental and harmonic components of flux with a sinusoidal time-varying surface magnetising force.

DOI:10.1049/ip-b.1980.0037

出版商:IEE    

年代:1980

数据来源: IET

摘要:

Doubly-fed slip-ring machines have two notable properties; a very high peak-power capability and a range of synchronous speeds not found in more conventional synchronous machines. However, in general, these machines suffer from dynamic instability caused by negative damping torques and attention has been focused on devising means by which their effect can be eliminated, to produce a satisfactory machine. A new technique is described, in which stable operation is attained by combining the unstable operation of the machine at two load angles. Two methods of applying the technique to a machine are described, in which stable operation is obtained without any measurable adverse effect on steady-state performance.

DOI:10.1049/ip-b.1980.0038

出版商:IEE    

年代:1980

数据来源: IET

摘要:

The paper presents the results of an experimental and theoretical investigation of a disc-geometry homopolar synchronous machine with field excitation on the primary side. The unlaminated mild-steel rotor contained no windings and was brushless. The prototype machine produced approximately 75 kW of mechanical output at 3000 rev/min, with a product of power factor and efficiency greater than 0.7. The construction of the stator core was unusual and incorporated both laminated and unlaminated portions. The magnetic circuit was also arranged to minimise the axial force between the stator and rotor. A novel rotor design which achieved a reduced quadrature-axis reactance is shown experimentally to be superior to the conventional homopolar rotor. A three-dimensional magnetostatic computer program ‘GFUN’ is shown to predict closely the flux densities prevailing in the machine. The quadrature-axis reactances calculated from these results also agreed well with measurements. An analytical method of calculating the axial force in the machine is validated by comparison with experimental data. The method uses the principle of Maxwell's stresses, and is based on the two-axis model of the machine. Prediction of the steady-state synchronous performance of the machine is also shown to be possible, using the two-axis model, provided that the assumptions implicit in that model are valid for the operating conditions of the machine. However, it was found that the output of the machine could be improved by a substantial amount by producing a degree of saturation in the magnetic circuit by means of the field winding. Under these conditions, the output of the machine exceeded predictions.

DOI:10.1049/ip-b.1980.0039

出版商:IEE    

年代:1980

数据来源: IET

摘要:

A mathematical model is developed for a complete marine power installation, incorporating diesel-generator units, and induction-motor propeller and pump drives. The model is used in numerous studies associated with the prediction of the current and torque requirements of the two types of marine drive commonly encountered, including dual induction-motor-driven, variable-pitch propulsion units. Representative results are collected together to show the various conditions that give rise to operational transient behaviour. Various factors affecting the starting and operational characteristics of these drives are discussed and recommendations made for the overall electromechanical modelling necessary for the accurate simulation of the response to normal and abnormal disturbances possibly arising from in-service system operation.

DOI:10.1049/ip-b.1980.0040

出版商:IEE    

年代:1980

数据来源: IET

摘要:

Eddy-current density distributions in the solid yoke of a specially designed d.c. machine were measured with and without main poles in position, with the compoles alone excited from a variable frequency source. From the measured eddy-current density distribution curves and from the flux-density distributions in the airgap at the back of the compole, the eddy-current flow pattern around the shell is obtained. The instrumentation of the test machine, the layout of the current density probes and search coils in different parts of the magnetic circuit, and the various measurement techniques are also discussed.

DOI:10.1049/ip-b.1980.0041

出版商:IEE    

年代:1980

数据来源: IET

摘要:

The chattering of an electromagnetic contactor which may occur when, for example, an induction motor is started direct to line, is studied. Considerations relating to the attractive force of the contactor indicate how a critical voltage may be calculated at which chattering will occur. It is shown that the theoretical voltage obtained this way, is in close agreement with the corresponding measured figure.

DOI:10.1049/ip-b.1980.0042

出版商:IEE    

年代:1980

数据来源: IET