摘要:

The economical limit of power factor improvement in relation to capital outlay. It is shown that ifCis the capital cost of generating and transmission plant per kilowatt, andcis the cost of phase-improving plant per wattless kilovolt-ampere; then, writingα = c/C, it is economical (from the capital outlay point of view) to go on improving the power factor until sin φ = α, where φ is the angle of lag. The saving thereby effected is equal to 100[l – cos (φo– φ)] per cent, where cos φ0is the original power factor before improvement. A practical example is worked out to show the operation of this rule. The synchronous motor and static condenser serving exclusively for injecting leading kVA are considered. The rotary converter and the synchronous induction motor serving the double purpose of supplying power and injecting leading kVA are dealt with and their province is described. Various methods of starting the synchronous induction motor are illustrated. The paper then goes on to treat of phase advancers of the rotating type connected to the slip-rings of induction motors. The effect of such advancers upon the performance of the induction motor is illustrated by several examples, and the change in the shape of the circle diagram is worked out. The author then proceeds to give an expression for the apparent capacity of his “vibrator” in terms of the constants of the machine, and shows how to arrive at the size of vibrator required to suit any given conditions. The last section of the paper deals with meters and tariffs. Various methods of indicating kW maximum demand and wattless kVA are described and particulars are given of the tariffs employed by various power companies. Observations are made as to the fairness of these to consumers who improve their power factor.

DOI:10.1049/jiee-1.1923.0001

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0007

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0008

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0009

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0010

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0011

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0012

出版商:IEE    

年代:1923

数据来源: IET

摘要:

A new form of magnetic balance has been devised for the accurate measurement of the intensity of field at any point in the air path of a magnetic circuit, the instrument being sufficiently delicate to detect differences in intensity of field amounting to one line per square centimetre, whereas existing methods measure only the average intensity over the whole field, or are only sensitive to differences of 150 to 200 lines/cm2.The distribution of the lines of force issuing from the sides of a bar magnet has been plotted and the surface of the magnet discovered not to be an equipotential surface.Biot-Savart's law has been experimentally proved.

DOI:10.1049/jiee-1.1923.0013

出版商:IEE    

年代:1923

数据来源: IET

摘要:

The paper deals in a very general way with the use of electricity in collieries. The types of generators, motors and cables are explained, and the factors governing the use of each particular type are discussed.A brief outline of the mechanical plant used in conjunction with motors is given, including pumps, haulages, coal cutters and winders.Diagrams are given of a typical haulage, as used extensively in this country, a turbine pump, a disc coal cutter and a small electric winder.

DOI:10.1049/jiee-1.1923.0014

出版商:IEE    

年代:1923

数据来源: IET

摘要:

The objects of the paper are: (1) To describe briefly the chief constituent parts of a hydro-electric development, and their functions; (2) to discuss some of the economic factors controlling the development and operation of water-power plants; and (3) to consider the question of tidal power where it exemplifies the working of these economic factors.

DOI:10.1049/jiee-1.1923.0015

出版商:IEE    

年代:1923

数据来源: IET