No abstract

[1] Satellite laser ranging (SLR) data were used to determine the variations in the Earth's principal figure axis represented by the degree 2 and order 1 geopotential coefficients: C 21 and S 21 . Significant variations at the annual and Chandler wobble frequencies appear in the SLR time series when the rotational deformation or "pole tides" (i.e., the solid Earth and ocean pole tides) were not modeled. The contribution of the ocean pole tide is estimated to be only ∼8% of the total annual variations in the normalized coefficients: C 21 /S 21 based on the analysis of SLR data. The amplitude of the nontidal annual variation of C 21 is only ∼ 30% of S 21 from the SLR time series. The estimates of the annual variation in S 21 from SLR, the Gravity Recovery and Climate Experiment (GRACE) and polar motion excitation function, are in a good agreement. The nature of the linear trend for the Earth's figure axis determined by these techniques during the last several years is in general agreement but does not agree as well with results predicted from current glacial isostatic adjustment (GIA) models. The "fluid Love number" for the Earth is estimated to be ∼0.9 based on the position of the mean figure axis from the GRACE gravity model GGM03S and the mean pole defined by the IERS 2003 conventions. The estimate of C 21 /S 21 from GRACE and SLR provides an improved constraint on the relative rotation of the core. The results presented here indicate a possible tilt of the inner core figure axis of ∼2°and ∼3 arc sec displacement for the figure axis of the entire core.

No abstract

No abstract

No abstract

No abstract

This paper presents the design and analysis of a new doubly salient permanent magnet (DSPM) motor. The corresponding output power equation is analytically derived. The initial calculation of motor dimensions and parameters, namely, the core diameter, stack length, permanent magnet size, and winding turns, are also discussed. An 8/6-pole DSPM motor is designed and built for exemplification. Moreover, finite element analysis of this motor is carried out to investigate the magnetic field distribution at different rotor positions and load currents, in which the leakage flux outside the stator circumference of the DSPM motor is firstly taken into account. Hence, the characteristics of the proposed motor are deduced. Experimental results of the prototype are given to verify the theoretical analysis and to confirm its high efficiency.Index Terms-Doubly salient motor, finite element analysis, leakage flux, permanent magnet (PM) motor, sizing equation.

No abstract