DOI:10.1049/jiee-1.1929.0002

出版商:IEE    

年代:1929

数据来源: IET

摘要:

The following paper describes an investigation of the operating current of the electric motors ordinarily used for starting motor-car engines. The standard type of Duddell oscillograph was used to record the startor current and the voltage at the terminals of the car battery respectively. The tests were made on three cars, one of which was fitted with a different type of startor from the other two. A large number of tests were carried out on the three cars, showing the effect of various conditions on the operating currents. A selection of typical oscillograms is reproduced in the paper, which also includes tabulated summaries of the results obtained on each of the three cars. These tables show the maximum currents recorded, the speed of the engine being driven by the startor motor, the time required to start up the engine, and the quantity of electricity discharged from the battery during the starting operation. In the discussion of the results a comparison is made between the results obtained on the two types of startor employed and of the effect of engine temperature upon the starting conditions.In the last section a description is given of a brief investigation carried out to locate the cause of the somewhat peculiar current peak which was observed in connection with one type of startor.

DOI:10.1049/jiee-1.1929.0003

出版商:IEE    

年代:1929

数据来源: IET

摘要:

In this paper the free period of an alternator is considered in relation to the other machines which may be coupled to the busbars, the following cases being examined:-(1) Two alternators working in parallel.(2) Two alternators working in parallel on an infinite busbar.(3) Two alternators working in parallel and connected to an infinite busbar through reactance.(4) Three alternators working in parallel and connected to an infinite busbar through reactance.(5) Three alternators working directly in parallel.(6) Three alternators working in parallel on an infinite busbar.(7) An alternator working on an infinite busbar driving a frequency-changer of the synchronous-motor type supplying an infinite busbar.In case (1) a formula is derived for the natural free period of two machines which may be compared with that of Mr. Everest, † and it is shown that the two machines together have only one resonant frequency.In case (2) it is shown that interaction between machines does not occur when working on an infinite busbar.In case (3) it is shown that two machines connected in parallel and joined to an infinite busbar through a reactance give a resonance, curve exhibiting two peaks.In case (4) the combination is found to be capable of resonant response to three frequencies, while in case (5) only two resonant frequencies appear.With three machines on an infinite busbar [case (6)], confirmation is obtained of case (2), three separate frequencies being present without interaction between the machines.In case (7) two resonant frequencies are found.*

DOI:10.1049/jiee-1.1929.0004

出版商:IEE    

年代:1929

数据来源: IET

摘要:

In this paper consideration is given to the applicability of the reciprocal theorem to the practice of radio direction-finding with either a rotating loop transmitter or a loop receiver. A description is given of some experiments carried out with the object of demonstrating that the permanent errors to which a rotating-loop beacon transmitter may be subject as a result of conditions local to its site are similar to those observed on a direction-finder erected on the same site. This similarity has materially assisted in locating the cause of the permanent error associated with the rotating beacon erected at Fort Monckton, near Gosport. From other experiments carried out under suitable conditions, it is shown that the occurrence of night errors is experienced on both systems of direction-finding to approximately the same extent.

DOI:10.1049/jiee-1.1929.0005

出版商:IEE    

年代:1929

数据来源: IET

摘要:

The paper gives an analysis of the variation with the resultant anode circuit load of the input impedance and voltage magnification factor of a triode valve. A new mode of presentation is adopted which enables the total range of variation of these quantities to be represented as finite functions of a variable with a limited range of variation.The most important conclusion is that at very high radio frequencies the voltage magnification factor may appreciably exceed the voltage factor of the valve, this condition being reached for a finite pure inductive load. Under the same conditions, however, the shunt input impedance is very low.The most efficient means of associating a tuned circuit with a receiver of relatively low input impedance is considered in an Appendix.

DOI:10.1049/jiee-1.1929.0006

出版商:IEE    

年代:1929

数据来源: IET

DOI:10.1049/jiee-1.1929.0007

出版商:IEE    

年代:1929

数据来源: IET

DOI:10.1049/jiee-1.1929.0008

出版商:IEE    

年代:1929

数据来源: IET

DOI:10.1049/jiee-1.1929.0009

出版商:IEE    

年代:1929

数据来源: IET

DOI:10.1049/jiee-1.1929.0010

出版商:IEE    

年代:1929

数据来源: IET

DOI:10.1049/jiee-1.1929.0011

出版商:IEE    

年代:1929

数据来源: IET