Along with bearing failures, insulation breakdown is one of the most common types of winding failures in electric motors. Insulation breakdown can happen for a number of reasons. Environmental factors are a main cause of insulation breakdown, which includes exposure to contaminants and debris. Abrasion can also cause the insulation to break down. Problems within the motor can also cause the winding insulation to break down more quickly than it should, including voltage surges. Motors that are used outside of their recommended operating conditions and tolerance ranges may experience insulation breakdown more rapidly as well.