Effect of parameters on back-EMF in permanent magnet brushless DC motor with concentrated winding
A method for analyzing the concentrated windings back-EMF in permanent magnet brushless DC motor, based on the analytical calculation of one phase back-EMF by using Fourier series, has been developed and validated by comparing computing waves to measured waveforms. And the paper discussed the influence on back-EMF of design parameters.
Airgap magnetic field estimation for IPM rotors considering their non-uniform local saturation
A saturation map for the non-uniform magnetic saturation of a V-shaped interior permanent magnet rotor is formulated in this paper. This saturation map is used in conjunction with the magnetic equivalent circuit theory to propose an analytical method for accurate computation of the airgap permanent magnet flux density for interior permanent magnet rotors. Unlike the conventional methods, the proposed technique accounts for the rotor non-uniform local saturations and relative permeability variations. The proposed permanent magnet flux density model is further used or analytical calculation of the back-EMF in interior permanent magnet machines. The proposed methodology is compared against the conventional analytical techniques and validated through experimental results on a prototype interior permanent magnet machine.
Fear of Crime in Relation to Three Exterior Site Features
This article examines fear of crime in relation to exterior site features on a college campus. The authors propose and test a theoretical model that posits that places that afford offenders refuge, and victims limited prospect and escape, will be seen as unsafe. In three studies, the authors observed behavior, obtained responses to site plans and on-site responses to perceptions of safety in relation to exterior campus areas that varied in prospect, refuge, and escape. The findings confirmed that fear of crime was highest in areas with refuge for potential offenders and low prospect and escape for potential victims. In places such as campuses, which have pronounced fear of crime, designs that manipulate prospect, refuge, and escape could reduce the fear of crime, as well as opportunities for crime.