The dynamics is studying for rigid body rotating around fixed axis O_z being central but not principal. Therefore the inertial torques M_x and M_y arose depending both on mass geometry J_xz, J_yz  and on angular velocity ε and acceleration ε. Dry friction acting on axis’s supports with coefficient δ leads to that the value of ε serves as the reason and result of the motion simultaneously. There  were integrated numerically and/or analytically the dynamical equations of free and forced motion  including rotational harmonic and inharmonic oscillations too. The results obtained are comparing  with those following from the standard linear equations.