Results of numerical modeling of squirrel-cage asynchronous motor with rotor circuit damages are presented in the paper. Possibilities of machine state rating in normal exploitation, based on the moving RMS signal and also proposed motor drive state estimation factors are also included. For modeling of the machine and proposed algorithm, the original program solution based on built C++ class library had been used. It had been shown, that the application of currents and voltages symmetry estimation factors and moving RMS currents and voltages diagrams oscillation estimation factors provides the identification of damage location. Analysis of proposed factors values makes the basis for indicating of damage location - either the supply source, or the stator circuit, or the rotor circuit asymmetry. Modeled damages have shown that not only the number of damaged rotor bars, but especially their symmetry in the rotor circuit has relevant meaning. Presented simulation results are being used for testing of proposed algorithms and building of a diagnostic device, based on Analog Devices SHARC 21065L processor.