Cracked leads are a type of winding motor failure caused by excessive stress and strain. Cracked leads can appear where stress raisers (also called stress concentrations) occur. Shaft damage or corrosion can cause stress raisers, which in turn may result in cracked leads. Cracked leads, which are also called fatigue cracks, can occur from repeated stress. Corrosion is another possible cause of cracked lead motor winding failures. Corrosion can be caused by exposure to environmental stresses such as heat and humidity. Ultimately, the leads may fail, and eventually full motor failure may result if the problem is not fixed.