摘要:

The scarcity of precise and detailed information on the several domestic applications of electricity encouraged the author to write a succinct account of the arrangements adopted in a 10-roomed house designed and built in Glasgow for all-electric working. In this house neither coal nor gas is used. The sections dealt with are:-(1) Layout of house.(2) Distribution board.(3) Wiring.(4) Bells.(5) Lighting.(6) Clothes-washing and drying.(7) Cooking.(8) Hot water.(9) Ventilation.(10) Heating.(11) Running costs.(12) Conclusions.The total cost of 16 584 units used in one year's working was £43 8s. The consumption and costs are analysed for the several services.In an Appendix, the results of a 4-roomed all-electric flat are given. The consumption for one year was 4 656 units and the total cost of energy was £14 18s.

DOI:10.1049/jiee-1.1926.0014

出版商:IEE    

年代:1926

数据来源: IET

摘要:

The paper consists roughly of two parts—an examination of the efficiency of electrical machinery of varying sizes, and an application of the results to the problem of economic choice. In the former section it is shown that wherever there is more than one kind of loss a large machine will have a higher efficiency than a small one, by an amount which is roughly predicable. It is further shown that this efficiency can be maintained with little or no diminution when the machine is suitably under-run, depending on the kinds and proportions of the losses. This makes it possible to calculate the cost of improving the efficiency of a given service to any required degree through the employment of larger plant than is physically necessary.Applying this to the selection of apparatus to fulfil a given service at the least total cost, the cases considered are squirrelcage induction motors, small d.c. motors and single-phase transformers. Placing all items on an annual basis, the rates of change of the various charges with reference to the frame size are worked out for a range of sizes in each of the three cases. These rates of change form an index by which the most economical size can readily be estimated for any conditions of service, and the method of doing this is fully explained in the paper.The results suggest that where the hours of service are long or energy is expensive a far larger or more efficient machine is justified than would normally be employed. Where such improved efficiency is proposed, the method here developed makes it possible to calculate the particular degree of improvement which is economically justified in any case. Such a calculation should be an essential feature of the design (or failing this, the selection) of all apparatus for long-hour service.

DOI:10.1049/jiee-1.1926.0021

出版商:IEE    

年代:1926

数据来源: IET

摘要:

The paper is divided into six parts, as follows:-In Part I the variations of frequency which occur in mechanical oscillating systems with pendulum control are referred to. Unless the driving impulses are given at the moment the pendulum is vertical, the frequency of the oscillations varies from the true oscillation frequency of the pendulum. When the pendulum is near the limit of its swing an impulse directed inwards makes the clock go fast, whilst an impulse directed outwards makes the clock go slow. Such an effect is “reversible” because the clock goes fast or slow according to the direction in which the impulse is applied. Another type of variation is connected with the amplitude of the swing, and makes its appearance unless the amplitude is infinitesimal. Increase of amplitude always makes the clock go slow, and the effect is therefore “irreversible”In Part II the phase relationships of currents and potentials in a thermionic generator arc examined, and it is shown that the frequency of the oscillations is affected by the nature of the coupling between the grid and anode circuits. Equations are obtained which give the difference between the frequency of the oscillations generated and the resonant frequency of the tuned circuits. These equations show that the variations of frequency connected with the method of coupling are analogous to the reversible variations existing in the pendulum-controlled clock. With normal coupling the thermionic generator goes slow, with reversed coupling it goes fast, and with resistance coupling the variation disappears.In Part III three “irreversible” variations of frequency are discussed, namely :-(i) A variation connected with a change in the effective inductance of the circuit, which occurs when the oscillation is free instead of forced;(ii) A variation connected with a change in the resonant frequency of a damped circuit, which occurs when the oscillation is free instead of forced; and(iii) A variation associated with the presence of harmonics in the E.M.F. generated by the valve.In Part IV certain points in the design of thermiornic generators employing resistance coupling are discussed.In Part V the design of thermionic generators using reversed coupling is discussed, and some interesting points affecting the design of untuned circuits are described.In Part VI the experimental results obtained with various types of circuit are given, and are explained in terms of the theoretical variations discussed in Parts II and III.The characteristics of various types of constant-frequency generator are then compared. It is pointed out that frequency variations associated with changes in the voltage of supply can be reduced below 1 part in 20 000, or 1 part in 50 000, according to circumstances.

DOI:10.1049/jiee-1.1926.0022

出版商:IEE    

年代:1926

数据来源: IET

摘要:

The paper is divided into sections as follow:-1.General2.Materials(a)Stator.(b)Rotor.3.Tests for flows.— The following methods are dealt with:-(a)Clink detection.(b)Optical tests.(c)Chemical tests.(d)Overspeed tests.(e)X-rays.(f)A successful potential-drop tests development by the G.E.C. Development Department. The results are published for the first time.4.Mechanical design.—This is considered from the point of view of the variation of the strength of the forging with radial depth and the efficiency of ventillation. Wedges and end-bell stresses, factor of safety, methods of test, and the available materials are dealt with. In the case of the rotor the best methods of determining the strength of the steel at the tooth root are fully discussed and methods of improving the strength of rotor forgings generally are suggested.5.Ventilation and liquid cooling.—Comparison is made between:-(a) Liquid and air cooling.(b) Wet and dry air filters and closed air systems.(c) High-speed and low-speed separately driven fans.Results of experiments on the effect of core spacers and wedges on volume and pressure of air are given.6.Insulation and temperature distribution.(a) Measurement of temperature by thermo-couples.(b) Recommended methods of insulating.(c) Maximum temperatures.7.Balancing.—A method is suggested whereby it is possible to move the balance weight at full speed. This may be worth while developing.

DOI:10.1049/jiee-1.1926.0024

出版商:IEE    

年代:1926

数据来源: IET

DOI:10.1049/jiee-1.1926.0027

出版商:IEE    

年代:1926

数据来源: IET

DOI:10.1049/jiee-1.1926.0028

出版商:IEE    

年代:1926

数据来源: IET