摘要:

The paper deals with part of a comprehensive investigation which is being carried out by a manufacturer of electrical plant on the noise emitted by machinery and other apparatus, a subject of great present and future importance. The need for treating the subject in a thorough and quantitative manner for engineering purposes is pointed out. The physical magnitudes involved in the measurement of the sound set up by a vibrating body are discussed generally, together with the characteristics of the ear. The characteristics that should be possessed by a sound-measuring apparatus intended for use in engineering problems are pointed out and a brief survey is made of existing types of apparatus. The principle, development and final form of the apparatus, which enables a complete analysis of a complex sound to be made, are described, together with the methods employed to verify the accuracy of the apparatus. The influence of the conditions under which sound measurements on engineering apparatus are carried out is discussed, and a special laboratory which has been set up for acoustical work is described. Some sound-test results on engineering apparatus are given as examples.

DOI:10.1049/jiee-1.1930.0001

出版商:IEE    

年代:1930

数据来源: IET

DOI:10.1049/jiee-1.1930.0005

出版商:IEE    

年代:1930

数据来源: IET

DOI:10.1049/jiee-1.1930.0006

出版商:IEE    

年代:1930

数据来源: IET

DOI:10.1049/jiee-1.1930.0007

出版商:IEE    

年代:1930

数据来源: IET

DOI:10.1049/jiee-1.1930.0008

出版商:IEE    

年代:1930

数据来源: IET

DOI:10.1049/jiee-1.1930.0009

出版商:IEE    

年代:1930

数据来源: IET

摘要:

In connection with the testing of wireless receivers, information was desired concerning the field strength obtained from 5XX in Cornwall, this district being known to be poor from the point of view of wireless reception.An investigation of the field strength was therefore carried out with the aid of portable equipment. This particular apparatus was simpler than that usually employed but appears from the consistency of the results to be reliable.When the experiments were conducted, a curious effect was brought to light which appeared to be a radio shadow caused by the masts of the beam station at Bodmin. This gives rise to an interesting distribution of the contours in the Truro district.The general order of field strength appears to coincide with theory up to this point, if due allowance is made for attenuation, but there is a rapid falling-off towards the extreme west of Cornwall.

DOI:10.1049/jiee-1.1930.0010

出版商:IEE    

年代:1930

数据来源: IET

摘要:

The analogy between the absorption of energy by a coil free to rotate in a constant magnetic field and the charging of an electrostatic condenser was pointed out by Swinburne in 1902, and was again stated by Kapp in developing the theory of his vibrator.The phenomenon of instability of direct-current shunt motors with interpoles was treated by Siebert, Wagner, Rosenberg and others, while the instability of differntially compounded motors was dealt with by Greve and Andrade. In the present paper, the correspondence between electrostatic and “dynamical” capacities is re-stated in a some-what different form, and the theory of the instability of compounded motors is developed as an extension.A series of experiments is described, the results of which are cited as confirmation of the results obtained by the mathematical analysis, and, in the appendix, details of the solution of certain of the equations are given.

DOI:10.1049/jiee-1.1930.0011

出版商:IEE    

年代:1930

数据来源: IET

摘要:

A quick and ready method of measuring the ratio and phase angle of high-voltage transformers is described in which the well-known high-voltage Schering bridge is employed. Formulæ for the voltage ratio and phase angle are given, together with expresssions for the sensitivity of the bridge. The accuracy obtained by the method meets the requirements of all industrial tests as well as of research work.

DOI:10.1049/jiee-1.1930.0012

出版商:IEE    

年代:1930

数据来源: IET

DOI:10.1049/jiee-1.1930.0013

出版商:IEE    

年代:1930

数据来源: IET