DOI:10.1049/pi-2.1953.0001

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-2.1953.0002

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-2.1953.0003

出版商:IEE    

年代:1953

数据来源: IET

摘要:

By using the well-known 2-axis theory of Blondel the paper develops on a simple geometrical basis the steady-state characteristics of synchronous salient-pole machines. From these it is shown that appreciable economies can be realized by relating the short-circuit ratio, and thus the synchronous reactance, of an alternator to the stability characteristics required by the load. It is also shown that further economies can be obtained in both alternators and synchronous condensers by designing the excitation system to supply positive and negative field currents.Power-station operation can be simplified and made more reliable by the use of a combined watt- and VAr-meter with a dial based on the power chart evolved in the paper.The common basis underlying the operation of the salient-pole alternator, synchronous motor and condenser, and synchronous reluctance machine is shown by a simple generalized diagram, and the operation of these types of motors is briefly discussed.Equations are evolved for determining machine characteristics with greater accuracy than is given by the geometrical method.

DOI:10.1049/pi-2.1953.0004

出版商:IEE    

年代:1953

数据来源: IET

摘要:

It is demonstrated that a systematic application of the theory of symmetrical components to the phase quantities of a symmetrically-wound induction motor provides a general method of analysis which can be used to predetermine the performance characteristics of the motor for any form of asymmetrical primary connection. Among the particular forms of asymmetry considered in some detail are abnormal connection of the primary phases and the insertion of asymmetrical line impedances or auto-transformers.It is noted that discrepancies in published work on the subject are due to ignoring the presence, or incorrectly assessing the effect, of the zero-sequence system; this system is therefore given special attention. Experimental results confirm the validity of the general method.

DOI:10.1049/pi-2.1953.0005

出版商:IEE    

年代:1953

数据来源: IET

摘要:

Difficulties are sometimes encountered in generating the standard 1/50-microsec impulse-voltage wave, free from excessive oscillations, when testing low-voltage windings of large transformers. The paper shows that a circuit using inductance and resistance to control the wavefront can be made to give a better waveshape than a circuit in which the shape of the front is controlled by resistance and capacitance. The improvement is illustrated by waveforms taken during tests on a 33-kV 30-MVA transformer winding. Given suitable circumstances, the suggested method of wave control should overcome some of the difficulties previously encountered.

DOI:10.1049/pi-2.1953.0006

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-2.1953.0007

出版商:IEE    

年代:1953

数据来源: IET

摘要:

The increasing demand for electrical windings to be impulse tested has led to the study of the factors affecting the distribution of impulse voltages along the conductors. To obtain the essential test information it is necessary to record oscillograms of the voltage at various points along the winding when an impulse voltage is applied to the line terminal. In the normal way this would require removal of the conductor insulation to make connections to the windings.The paper describes two methods of utilizing a capacitance tapping on the conductor whereby any damage to the winding insulation is avoided. In the first method a simple capacitance voltage-divider circuit is used between the deflection plates of the cathode-ray oscillograph and the winding, the connection to the winding being obtained by wrapping a piece of foil round the outside of the conductor insulation. Better results are obtained, however, by using a suitably designed cathode-follower circuit between the tapping foil and the cathode-ray oscillograph. Consistent results were obtained for impulse waves chopped in times as short as about 0.07 microsec, corresponding to a frequency of about 4 Mc/s when a capacitance greater than 300μμF was used between the tapping foil and the winding.

DOI:10.1049/pi-2.1953.0008

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-2.1953.0030

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-2.1953.0031

出版商:IEE    

年代:1953

数据来源: IET