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The article presents a calculation of a turbogenerator rotor air-cooling system with self-ventilation of the rotor winding from a sub-slot duct. The mathematical model proposed in the article reflects all the significant geometric parameters of the physical model as well as the gas dynamics of the cooling process. Research has been done into the impact of the profile of a sub-slot duct along the length of the rotor on air velocity distribution in radial ducts and on the efficiency of heat transfer in a 320 MW turbogenerator. The research has also shown that the maximum temperature of the rotor winding may be lowered by means of a sub-slot duct smoothly tapering to the middle of the axial rotor length (17% of the inlet section area of the sub-slot duct). Such configuration compensates air heat up along the rotor sub-slot duct due to the forced unevenness of air distribution in the radial ducts. [ABSTRACT FROM AUTHOR]

The use of sensitive electronics in avionics and wind generation systems, as well as the introduction of lower-conductivity composite materials make it important to ensure adequate lightning testing of airplanes and wind turbines. Evidence exists suggesting that standardized testing lightning waveforms produce damages that differ from those observed in actual strike events. The applicability of the present standard current waveforms for lightning testing is assessed in this paper and it is argued that waveforms based on upward flashes may be better suited as a basis for testing than the currently used tests, which are based on downward lightning and on airborne measured current bursts. Upward lightning data obtained at the Säntis Tower in Switzerland are also presented to support the need to revisit current waveforms used in standardized aircraft testing. [ABSTRACT FROM AUTHOR]

A mechanism to demodulate a two-tone high-frequency oscillation in nonlinear electronic devices due to an external electromagnetic field is investigated. The results of a demodulation are low-frequency disturbances to the internal circuits of electronic devices. A method for the synthesis of nonlinear compensators on the basis of the operational equations of electronic devices is offered for protection against low-frequency noise. The nonlinear operator of the compensator is designed so that a cascade connection of the electronic device and the compensator is described by the linear Volterra functional. As an example, the compensation of nonlinear transformations of a detector at high-frequency oscillation is synthesized with the use of results of measurements. The accuracy of the executed compensation is estimated [ABSTRACT FROM AUTHOR]

A new method of deembedding a test fixture effect from the data of microwave measurements is presented in this paper. It is shown that the traditional unterminating problem (the problem of finding fixture characteristics) being posed in a finite frequency range may be reduced to a problem of fitting the characteristics of the ‘thru’ experiment. The latter is proposed to be solved by using the genetic algorithm (GA). A special trick is suggested to take fixture power loss into consideration, which is sometimes necessary to increase the goodness of fitting the characteristics. Physically correct constraints for optimization variables and optimal parameters of the GA are discussed in this paper. The method is applicable for all microwave fixtures, except for those whose characteristics are influenced by the relative position of the adapters comprising the fixture. The method does not have any specific frequency limitation and does not require any calibration standards. The results of the experiments performed have validated a high efficiency of the method proposed, and confirm that the accuracy of a deembedding problem solution is close to the goodness of fitting data of the ‘thru’ experiment. [ABSTRACT FROM AUTHOR]