The present disclosure discloses a device and a method for condition monitoring and protection of rotating electrical motors. The device receives measurements of current flowing in a power line connected to the rotating electrical machine. The device extracts a frequency band content containing information representative of condition of rotor bar from the measured current signal using wavelet filters. Further, the device compares the frequency band contents with a predefined threshold value and identifies a condition of the rotor bars. The condition includes damages caused to the rotor bars. Based on the condition, the IED generates one or more status signals (alarm signals or trip signals). The trip signal is provided to a switch connected to the power line to disconnect the rotating electrical machine.