Mean-field electrodynamics, including both the α-effect and the effect of Lorentz forces damping action on small-scale helical fluid motions (the latter taken in the limit of low magnetic Reynolds number values) is formulated for the electrically conducting, rotating, inviscid Boussinesq fluid. A self-consistent system of two coupled ordinary differential equations in terms of mean magnetic field intensity and helicity bulk density is derived for the case of spatial homogeneity and isotropy. The mean-field induction equation takes into account both the α-effect and the effect of magnetic viscosity. The helicity balance equation contains the helicity source due to buoyant forcing and the helicity sink because of Ohmic dissipation. This system has the unique stationary solution, which is the global attractor, and describes the saturated values of mean magnetic field intensity and helicity. Possible implications to the problem of the terrestrial magnetism are discussed briefly.