The main advantage of condition monitoring by analyzing vibrations on rotating machines is the possibility of detecting faults before a failure occurs leading to the unplanned stoppage of a machine. The unbalance defect is the most common and most frequently encountered cause of vibration, it is also one of the main causes of reduction in the life of machines and it constitutes one of the main risks for Security. This paper is devoted to the experimental study of the two types of unbalance defects, their different vibratory signatures and how to differentiate their vibratory behavior from other mechanical faults which manifests itself by the presence of a peak at the rotational frequency in the case of combined faults.