Current-based detection of eccentric load coupled to brushless DC motor

This paper proposes a new diagnosis method for the eccentric load coupled to a brushless DC motor, which utilizes the amplitude of two-phase current. The experiment verifies that the Fourier analysis and the Wavelet analysis of the amplitude of two-phase current are effective. Especially, the Fourier analysis of the amplitude of two-phase current is proportional to the load torque with the coefficient of the inverse of torque constant at a low speed. The proposed method is very useful to estimate the amount of eccentric load using the stator current.