I read interesting article regarding Halbach arrays and magnetic levitation (see www.lmco.cn/data/assets/9197.pdf[/URL]). In the article (see equation 1) the author states that the voltage generated by moving magnet over rectangular coil is V= L*dI/dt + RI = [tex]\omega \Phi cos(\omega t)[/tex] Where [tex] \Phi[/tex] is the peak magnetic flux and [tex] \omega[/tex] is the frequency defined by the wavelength of the Halbach array. Where does the right side of this equation come from. Is it derivative from sin function containing the omega and phi? How is this equation formed? I'm puzzled..