The paper presents a simplified method to detect rotor bar faults at steady state operation in squirrel cage induction motor (IM) by using stator current envelope. Three different rotor faults and healthy motor conditions were investigated in experiments. One of the stator currents has been used in the investigation of effects of rotor faults on the current envelopes. The ratio of fluctuations of the envelope was used as features of fault conditions for diagnosis. In the literature, a lot of studies are available about diagnosis and detection of rotor faults by using many different analysis and feature extraction methods. Unlike the literature, in the present study, the stator current envelopes are used. Experiments were made by using four different submersible IM. The experimental results show that the purposed method detects rotor bar faults from healthy motor with zero error. In addition, the method classifies the rotor faults with 9.4% error. This study shows that the used method can be successfully used to detect rotor bar faults. So, less computation and low cost are provided in implementation, which would make it easier to implement in embedded systems for condition monitoring of motor.