When the dissipation increases there a maximum in the damping ratio relative to the coupled vibration mode, the lower branch in the plot.

The electrical dissipation D has to be large enough to assure damping but small enough to not uncouple the eigenvectors, allowing the flux of mechanical into electrical energy! The optimal value is around D = 1.8 C.

For B = A, and D = 1.8 C, the plot represent the time-evolutions of the energies (colored as done before). Once the mechanical energy is transformed into its electrical form, it is now dissipated, till a complete rest of the system.