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1. |
A technique for investigating the electrical properties of oil-impregnated paper |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 213-215
H.C.Hall,
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摘要:
A description is given of a technique which has been developed for the investigation of the electrical properties of oil-impregnated paper, with special reference to the type of lapped-paper dielectric used in power cables.The equipment described is versatile, permitting a wide range of electrical tests to be made on one type of specimen and enabling the effect of variations in construction or component dielectric materials to be assessed rapidly and conveniently. The system is well suited for routine quality control as well as for research or development.
DOI:10.1049/pi-2.1954.0046
出版商:IEE
年代:1954
数据来源: IET
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2. |
The wear of carbon brushes at high altitudes |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 217-222
R.F.Sims,
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摘要:
The carbon brush depends for its frictional properties on atmospheric water. At high altitudes, where the atmosphere is very dry, friction is high and wear rate is catastrophic. Laboratory apparatus for the study of the phenomenon must simulate the conditions in the upper atmosphere. Conventional lubricants are unsuitable on account of their effect on the electrical contact and their failure to withstand the conditions at the rubbing face. Effective inorganic lubricants give immunity by building up a stable film on the commutator surface, but they adversely affect machine performance.
DOI:10.1049/pi-2.1954.0048
出版商:IEE
年代:1954
数据来源: IET
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3. |
A scaling unit employing multi-electrode cold-cathode tubes |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 227-238
K.Kandiah,
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摘要:
A complete scaling unit for counting regular or random pulses is described. The unit employs cold-cathode scaling tubes and trigger tubes in the main counting circuits. Various methods of driving cold-cathode scaling tubes are fully described. A novel method of driving the CV2271 scaling tubes is used in which the amplitudes and durations of the pulses to all stages in a cascade of these tubes are controlled directly by a common pulse generator, and cold-cathode trigger tubes are used as gating elements between the stages. A new type of pulse amplitude discriminator of high sensitivity is used at the input of the scaling unit. A simple system of marginal testing of the complete equipment is incorporated in order to obtain early indication of deterioration of tube characteristics.
DOI:10.1049/pi-2.1954.0051
出版商:IEE
年代:1954
数据来源: IET
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4. |
A sensitive pulse trigger circuit with a stable threshold |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 239-247
K.Kandiah,
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摘要:
A new type of trigger circuit for either positive or negative pulses is described in which the sensitivity or threshold is not dependent on the contact-potential variations in valves. A threshold of less than 100 mV with a stability of better than 2% can be achieved under practical operating conditions. The circuit can be used as a normal trigger circuit with less accurate threshold down to 5 mV. The conductances of a diode used in the retarding-field region and two other valves passing constant currents are the main factors which determine the sensitivity. Theoretical calculations of the sensitivity are given for the general case, and some experimental confirmation of the theory is also presented. The minimum pulse width for operating the circuit is shown to be of the same order as that for conventional pulse-amplitude discriminators.
DOI:10.1049/pi-2.1954.0052
出版商:IEE
年代:1954
数据来源: IET
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5. |
The development of a neutron spectrometer for the intermediate energies |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 248-259
F.S.Goulding,
J.C.Hammerton,
M.G.Kelliher,
A.W.Merrison,
E.R.Wiblin,
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摘要:
A very brief statement of the problems of nuclear reactor design prefaces an account of some of the nuclear-physics measurements necessary. The time-of-fiight neutron spectrometer installed at the Atomic Energy Research Establishment is described in detail with reference to these measurements. The performance of the machine, which makes use of a 3.2-MeV linear electron accelerator as neutron source, is shown in comparison with that previously published for other spectrometers. It is shown that the energy resolution obtainable at energies over 10 eV with the A.E.R.E. spectrometer is rather better than has previously been available for comparable counting rates. This is illustrated by comparison of experimental observations of the cobalt total neutron cross-section in the neighbourhood of a scattering resonance at 120 eV.
DOI:10.1049/pi-2.1954.0053
出版商:IEE
年代:1954
数据来源: IET
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6. |
Service experience of the effect of corrosion on steel-cored-aluminium overhead-line conductors |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 271-283
J.S.Forrest,
J.M.Ward,
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摘要:
The paper describes the experiments carried out during the last 20 years on the corrosion of steel-cored-aluminium overhead-line conductors on the Grid system. It is found that the average rate of deterioration, based on the reduction in mechanical strength, is 0.4–0.5% per year, and that the average service life of the conductor is 25–30 years. The rate of deterioration varies greatly in different localities, extreme values for the life of the conductor being from 3 to, say, 50 years.The mechanism of corrosion is described, and it is shown that there are two types of corrosion, one being associated with industrial districts and the other usually with coastal regions.The prevention of corrosion is discussed and information is given on service experience with greases and other protectives. Recommendations are made on methods of protecting conductors by treatment with a suitable grease.
DOI:10.1049/pi-2.1954.0064
出版商:IEE
年代:1954
数据来源: IET
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7. |
Electricity in the wool-textile industry |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 291-307
A.J.Francis,
T.H.Carr,
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摘要:
The paper indicates the importance of wool textiles as one of our principal exporting industries, stresses the need for greater production and higher efficiency, and shows the part that electricity is playing and can play in the industry.An outline of the industry and its development is given, and some the problems associated with the principal applications of electricity are discussed. Certain machine-drive problems are examined, and methods of overcoming them are suggested. Mention is made of the provision of power supplies. A glossary of terms used in the industry is given.
DOI:10.1049/pi-2.1954.0067
出版商:IEE
年代:1954
数据来源: IET
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8. |
Measurement of the winding resistances of a 132-kV power transformer in service |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 308-320
K.J.R.Wilkinson,
J.D.Harmer,
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摘要:
The star-winding resistances of a 132-kV power transformer were measured by superimposing direct current upon the 50–c/s load current while the transformer remained in service. From these measurements the winding temperature could be derived to within 3°C—an uncertainty due chiefly to the occurrence of the small fluctuations in system voltage which are inseparable from a normal power system in service. The special measures necessary to achieve this degree of accuracy include the provision of a filter stage with electronically enhanced time-constant. In comparison with the measurement of winding resistance of a transformer in service, results by a similar method applied to a power transformer while undergoing a short-circuit heat run show that winding temperatures could be assessed within 0.5°C. By measuring in this way the changes in temperature which follow a sudden change in load, close agreement has been found with the cooling correction rule given in B.S. 171: 1936. An Appendix discusses variations in direct-current distribution between the three star windings.
DOI:10.1049/pi-2.1954.0070
出版商:IEE
年代:1954
数据来源: IET
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9. |
The recovery of electric strength of an arc-discharge column following rapid interruption of the current |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 321-334
W.O.Kelham,
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摘要:
A new technique for investigating the recovery period is described. A rectangular pulse of arc current is used and a probing voltage impulse is applied to the decaying arc channel at varied delay times after current interruption. The method has certain advantages over the normal a.c. method of testing.Reignition-voltage/time curves are presented for different conditions of electrode material, gas, gap length, arc current, arc duration and reignition polarity, with gas pressures at or near atmospheric. Observations are also made on the dynamic characteristics of the electrical discharge following reignition.Polished-copper and polished-tungsten electrodes require a reignition voltage of 355 volts within 3 microsec after current interruption for arc currents of 20 amp and less. Pipped-copper, pipped-tungsten, mild-steel, aluminium and graphite electrodes show continuing emission of electrons after current interruption to a varying degree, with corresponding reduction of the reignition voltage.The reignition phenomena are markedly affected by the polarity of the reignition. The arc anode normally attains a higher temperature than the cathode, so that continuing thermionic emission of electrons is more prevalent. Thus reignitions of reverse polarity from the original arc discharge tend to be lower than those of the same polarity.Different gases recover electric strength in the order: sulphur hexafluoride, carbon dioxide, oxygen, air, nitrogen and argon.
DOI:10.1049/pi-2.1954.0072
出版商:IEE
年代:1954
数据来源: IET
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10. |
The propagation of surge voltages through large turbo-alternators with two parallel windings |
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Proceedings of the IEE - Part II: Power Engineering,
Volume 101,
Issue 81,
1954,
Page 335-340
B.C.Robinson,
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摘要:
The paper extends an earlier study of the propagation of a surge through an alternator with a single winding per phase to include large turbo-alternators with two windings in parallel–a type of winding used in machines carrying currents exceeding about 700 amp.It is usual to construct machines of this type with a short-chorded winding, in order to reduce the proportion of harmonics in the generated voltage. From a consideration of the winding arrangements in a machine of this type, it is shown that the impulse-voltage distribution in the two halves of the unimpulsed phases is not the same with a single-phase impulse. Similarly, the two halves of either of the impulsed phases have a different voltage distribution when an impulse is applied to two phases. It can, however, be shown that in these cases one half-winding from one phase may be paired with a halfwinding from the other phase. These deductions are confirmed by test results on a 50-MVA alternator winding. Test results for other machines are given to illustrate the relationships which were derived from theoretical considerations.
DOI:10.1049/pi-2.1954.0073
出版商:IEE
年代:1954
数据来源: IET
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