摘要:

This paper consists of a review, expressed in fundamental terms, setting forth the past development, the present position and the trend of progress as applying to pulverized-fuel firing and stoker firing. The relative positions of pulverized fuel and stokers, and of the “bin and feeder” system and the “direct fired” system, of pulverized fuel, are described in detail. The considerations governing the development of plant arrangement and of individual items of equipment entering into pulverized-fuel systems are discussed in the light of accumulated experience, the shortcomings and virtues of past designs being set forth with equal frankness.The combustion process in its relation to coal preparation and furnace and burner design is considered, and also the history of the pulverized-fuel furnace, beginning with solid refractory walls and terminating with the water-cooled and steam-cooled furnace.Improvements in stoker design and performance, and the necessity of improving stoker furnaces so as to meet modern requirements of rating, efficiency and preheated air temperature, also the factors defining the field of application of travelling-grate and retort-type stokers, are dealt with.Finally, a brief discussion of the problem of ash and grit discharge from the chimney and of its solution is included.

DOI:10.1049/jiee-1.1928.0128

出版商:IEE    

年代:1928

数据来源: IET

摘要:

This paper discusses the behaviour of reverse-power a.c. relays of the wattmeter and allied types when applied to the protection of 3-phase generators and feeders, and it shows:-(a) The differences in behaviour produced by various systems of connections;(b) The improper operations inevitable with each system of connections;(c) The difficulties to be overcome in order to produce a reverse-power relay which will be stable with all conditions of forward power and whose operation will yet be certain under all conditions of reverse power.In addition, the paper shows that the most satisfactory results available with this class of instrument will be obtained if the potential coils of the relay be connected between line and neutral when used for generator protection, or between line and leading phase when used for feeder protection.

DOI:10.1049/jiee-1.1928.0134

出版商:IEE    

年代:1928

数据来源: IET

摘要:

The design and operating features of rotary convertors are considered and compared with respect to the number of slip-rings.Particular attention is given to the armature reaction and analysis of the magnetomotive force wave-forms, with their effects upon commutating conditions.The d.c. voltage wave-form is also examined.These investigations show that, in general, the 9-ring rotary convertor is superior to both the 6- and 12-ring machines.Voltage regulation and starting are considered.Methods of obtaining symmetrical 9-phase voltage systems from 3-phase supply mains by means of suitable transformer connections are described and examined.

DOI:10.1049/jiee-1.1928.0135

出版商:IEE    

年代:1928

数据来源: IET

摘要:

Hitherto only two complete proofs of the circle diagram allowing for stator impedance and core loss have been published, viz. (1) Ossana's method of repeated inversion, †and (2) Lamme's algebraic proof. ‡Both of these methods have disadvantages. The first is, to the best of the author's knowledge, not accessible in English, while the second is long and involved and often difficult to follow. Further, neither of these methods gives any construction for the determination or graphic representation of the secondary equivalent current.A new proof is here published, which has the following features:-(1) It is a graphic proof throughout.(2) It gives an easy construction for the secondary equivalent current and, where the secondary winding is not short-circuited, for the secondary equivalent terminal e.m.f.(3) Its correspondence with the symbolic method is exact, so that at any stage in a problem symbolic methods may be substituted for graphical methods, or vice versa, with full confidence that the values obtained by the two methods are in exact agreement.Finally, the application of the diagram to the synchronous machine is developed.

DOI:10.1049/jiee-1.1928.0136

出版商:IEE    

年代:1928

数据来源: IET

摘要:

To solve the present farming crisis, agriculture will undoubtedly have to be industrialized by the aid of electric power. Considerable attention has been given to the applications of electricity in the farm buildings, but not so much to work on the land. Hence the subject of this paper, which covers the author's own experimental work and the result of experience of observing electric ploughs in operation in other countries, over 200 of these machines being now in use abroad. An electric plough can be usefully operated for 200 days in the year.To obtain a concrete idea of the work to be accomplished, some notes are given concerning the objects of ploughing, the efficiency of the implements, the power required and the differing classes of soil to be dealt with. Methods of electrical distribution and tapping for the necessary current supply are described. They are quite simple in principle and reasonable in cost. The principal practical types of plough are then described. These include the large double-winder steel-rope machnines, based upon 40 years' experience of British steam-plough practice. (These, of course, are only suitable for large areas and co-operative or contractor owning, as they cover 12 to 30 acres per day.) Also there is the newer development of the small calss of plough, suitable for the individual small farmer or market gardener. These are constructed on teh revived roundabout system and also on the tractor system. The author's idea of the best form of this smaller type of plough is given. Rotary tillers are briefly described. The cost of electric ploughing is discussed. An interesting large-scale development of electric plough contracting under the auspices of electricity supply undertakings is mentioned. The paper concludes with a list of the advantages of electric ploughing and with a bibliography of the subject.

DOI:10.1049/jiee-1.1928.0137

出版商:IEE    

年代:1928

数据来源: IET

DOI:10.1049/jiee-1.1928.0148

出版商:IEE    

年代:1928

数据来源: IET