Condition monitoring of electrical machines has received considerable attention in recent years. Many monitoring techniques have been proposed for electrical machine fault detection and localisation. These techniques include the measurement of stator voltage and current, air-gap and external magnetic flux density, output torque, internal and external temperature, and case vibration. However, no comparison between these technologies in term of sensitivity to faults has been given yet. This paper shows that experimental analyses of asymmetrical stator and rotor faults in three-phase induction motors by using vibration, phase current and transient rotor speed analysis. The performance and sensitivity of the above three techniques are given.