Abstract: The calculation formula of ellipsoid eddy-current and eddy-current moment under varying magnetic field are derived.It is known from the formula that the moment is proportional to the derivative of the magnetic field with time.The coefficient is a constant related to the ellipsoid＇s shape,size,and material.Then it can be used to calculate the eddy-current fields in the space by the moment.

Key words: ellipsoid, eddy-current, eddy-current moment, eddy-current coefficient