Simulating insulation systems under various environmental conditions in the laboratory

Over the last century as electrical motor testing became prominent in industry, little research has been published on simulating insulation systems in various environmental conditions such as moisture and contamination that are found in the field. In this paper, summary results of research performed using simulation software to simulate insulation systems in various environmental conditions that may be experienced in the field are presented. All simulations are based on actual nominal Insulation Resistance Profiles (IRP) obtained during a standard Polarization Index (PI) Test on motors (not containing stress graded systems). Once a nominal profile is obtained, the effects of changing various parameters of the standard insulation system model such as resistance-to-ground, and capacitance-to-ground, to simulate various environmental conditions are examined. Lastly, simulation results are compared to actual field case studies using some of the four basic Insulation Resistance Profiles (Nominal, Moisture, Contamination, and Embrittlement).