The second important parameter in obtaining a good modal analyse is the stiffness strong connected with the Young’s modulus. In the electric motor model there were considered the real values of the Young’s modulus for steel, aluminium and an equivalent value for the silicon steel core [4].
The FEM modal analysis was divided in two parts: in the first one there were considered, separately, all seven parts and there were found their natural frequencies and in the second step it was considered the assembly electric motor.
The single parts analysis was done to found the levels of natural frequencies in the perspective of defining the assembly natural frequency range.