Abstract: In this study, authors gives a monitoring technique of broken rotor bar and ring detection of squirrel cage induction motors. For diagnosis, we proposed model of squirrel cage induction motors under rotor faults where the machine inductances are calculated by means of the magnetic energy stored in the air gap. Diagnostic information is found in the spectrum of stator current. The current waveforms is analysed using Fast Fourier Transform (FFT). The rotor fault is manifested as an increase in the amplitude of the 2sf and other spectral components. Simulation test results show agreement between the healthy and faults machine.