Health monitoring of bearing and gear faults by using a new health indicator extracted from current signals

•Proposition of a practical and effective methodology for condition monitoring.•Construction of a new health indicator based on current signals.•Utilization of current signals to detect bearing, gear and combined faults.•Fault classification based on an improved ANFIS model.•Application of the proposed methodology on gearbox fault detection and diagnostics. Gear reducer motors play an important role in industry due to their robustness and simplicity of construction. However, the appearance of faults in these systems can affect the quality of the product and lead to significant financial losses. Therefore, it is necessary to perform Prognostics and Health Management (PHM) for these systems. This paper aims to develop a practical and effective method allowing an early fault detection and diagnostic for critical components of the gear reducer, in particular gear and bearing defects. This method is based on a new indicator extracted from electrical signals. It allows characterizing different states of the gear reducer, such as healthy state, bearing faults, gear faults, and combined faults. The diagnostic of these states is done by the Adaptive Neuro-Fuzzy Inference System (ANFIS). The efficiency and the robustness of the proposed method are highlighted through numerous experimental tests with different levels of loads and speeds.