DOI:10.1049/pi-2.1954.0001

出版商:IEE    

年代:1954

数据来源: IET

DOI:10.1049/pi-2.1954.0003

出版商:IEE    

年代:1954

数据来源: IET

摘要:

A description is given of the design, construction and development of a precision wattmeter-voltmeter-ammeter-milliammeter and a.c./d.c. transfer instrument used at the South African National Physical Laboratory for testing a.c. instruments.When used as a wattmeter, ammeter and voltmeter the instrument has current ranges of 0.5–5 amp, and voltage ranges of 25–500 volts.The milliammeter range is 50 mA.Results obtained with this instrument are accurate within 0.01% of full-scale value on either direct or alternating supplies of 50 c/s, and at power factors between unity and 0.5.Corrections have been established to permit of precise measurement at higher frequencies or at lower power factors.

DOI:10.1049/pi-2.1954.0004

出版商:IEE    

年代:1954

数据来源: IET

摘要:

The paper presents an elementary approach to the theoretical considerations upon which electrical analogues can be used to simulate hunting phenomena in power systems. The major assumption is that in the case of a deviation of the pole axis of the rotor of a machine from its normal steady-state condition, the amplitude of such angular displacement must be small. As an example, a simple electrical analogue is set up to simulate a given electro-mechanical system. The frequency and amplitude of natural oscillations determined experimentally on the analogue agree very well with the results of a mathematical analysis.In order to extend the scope to system stability problems, a 10-kc/s network analyser utilizing analogue-computer technique is described. The main object is to produce a unit capable not only of solving steady-state stability problems, but also of producing directly the system swing curves for transient problems, without the necessity for step-by-step computations, as are required with the usual a.c. network analyser. Further work on this analyser is being carried out and will be reported in a future paper.

DOI:10.1049/pi-2.1954.0005

出版商:IEE    

年代:1954

数据来源: IET

摘要:

An experimental method of determining the axial forces in power transformers is applied to a transformer constructed so that various tapping arrangements can be set up, and curves are given of the forces which occur with typical methods of tapping concentric windings.It is considered that the simple “residual ampere-turn” method of calculating axial forces is sufficiently accurate for design purposes, and a number of formulae are given which should cover most of the requirements of the transformer designer.The distribution of axial force around the periphery of the coils is investigated experimentally.

DOI:10.1049/pi-2.1954.0006

出版商:IEE    

年代:1954

数据来源: IET

摘要:

Measurements of the voltage required to produce discharges in voids within a number of different dielectrics show that the discharge-inception voltage across the void is independent of the nature of the dielectric and of the void position, including the case in which the void is bounded by one of the electrodes, but depends upon void depth or thickness in the direction of the applied electric field.The measurements, including those made at pressures and temperatures other than n.t.p., are consistent with Paschen's law for metal-to-metal breakdown of gas.

DOI:10.1049/pi-2.1954.0007

出版商:IEE    

年代:1954

数据来源: IET

摘要:

The paper describes a new and simple voltage-stabilizing circuit which is inherently capable of adjustment for infinite stabilization ratio and zero output resistance; the circuit is suitable for outputs of from 70 volts upwards, but has particular advantages for voltages of the order of 1–15 kV. The principle of operation is discussed, and the conditions necessary for optimum performance are investigated. Details of a practical circuit are given, and the performance limitations imposed by non-linearity of valve characteristics are dealt with in an Appendix.

DOI:10.1049/pi-2.1954.0009

出版商:IEE    

年代:1954

数据来源: IET

DOI:10.1049/pi-2.1954.0012

出版商:IEE    

年代:1954

数据来源: IET