DOI:10.1049/jiee-1.1939.0198

出版商:IEE    

年代:1939

数据来源: IET

摘要:

This paper deals with the circuits in direct-current potentiometers and details of their construction and use. The elementary circuits are first described, followed by the more elaborate ones necessary for precision potentiometers. Thermo-electric effects and other sources of error and methods of obtaining true zero are considered. Some practical details in the accurate measurement of current and voltage are discussed, as well as the devices used for these purposes. The special form of potentiometer used as a voltage standardizer is described.

DOI:10.1049/jiee-1.1939.0203

出版商:IEE    

年代:1939

数据来源: IET

摘要:

This paper deals with the existing systems for the conversion of 3-phase 50-cycle alternating current, to single-phase at 16⅔ cycles, with mercury-arc-mutators. Frequency-changing with mercury-arc mutators may be performed either with a direct-coupling mutator convertor or with a mutator convertor with intermediate direct voltage. The direct-coupling mutator convertor is characterized by the method of producing the single-phase voltage curve, which is built up from sections of individual 3-phase voltage curves; this method involves direct coupling of primary and secondary networks. The mutator convertor with intermediate direct voltage consists of a rectifier and an invertor having a d.c. circuit as intermediate element between the a.c. networks. No type of existing mutator convertor is perfect in itself. The future development of mutator convertors for traction purposes depends largely upon the demand for frequency-changing.

DOI:10.1049/jiee-1.1939.0205

出版商:IEE    

年代:1939

数据来源: IET

摘要:

The paper deals with a problem of axial deformation of the rotor windings of turbo-alternators having long rotors. This trouble has only been experienced in recent years, and while the cause has been referred to by other authors the reasons why only a part of the winding has been affected have not been explained.The present paper deals with the effect of temperature on the amount of deformation of different conductors throughout the depths of the slots, and shows that a comparatively small increase in temperature-rise may cause the deformation to become serious. A graphical method is given by which it is possible to determine whether a given temperature-rise will cause the deformation to become serious.The effect of different methods of applying excitation is set forth.

DOI:10.1049/jiee-1.1939.0206

出版商:IEE    

年代:1939

数据来源: IET

DOI:10.1049/jiee-1.1939.0211

出版商:IEE    

年代:1939

数据来源: IET