Field winding fault diagnosis in DC motors during manufacturing using thermal monitoring

Quality assessment during DC motor manufacturing should involve quality controls designed to detect various fault conditions associated with the components included in the machine. Some defects, however, can be produced by the automatic manufacturing process during the assembly of the individual components. Inter-turn short-circuits, turn to earth short-circuits and open winding, among other fault conditions, can result from the field poles manufacturing and insertion inside the stator. The main problem with these kinds of faults is that though the motor is likely to be operational, there is a high probability of motor breakdown in the near future. In this paper, the above fault conditions are analyzed and a thermal model and an infrared monitoring test method for manufacturing quality control is proposed. ► This research describes a simplified thermal model of a DC field winding. ► It is provided a test system and a methodology for testing. ► The system put forward works properly with open winding and inter-turn fault condition.