We analyze the collective excitations arising in perovskite type superconductor materials with two layers per cell. We discuss the influence of these excitations on the superconductor properties. Calculations are performed in the frame of a B.C.S. theory which takes into account the bidimensionality of the layers and the long range electromagnetic coupling between them. The strong electromagnetic coupling between CuO2 layers belonging to the same cell leads to the appearance of two low‐frequency modes. For the first mode the Tc raises with the interlayer distance d, while for the second mode Tc diminishes with the increasing of d.