Lifetime Estimation of Vehicle Alternators

• Published in: 2022 25th International Conference on Electrical Machines and Systems (ICEMS) pp. 1 - 6
• Main Authors: Iacob, Alexandru, Notingher, Petru, Stancu, Cristina, Setnescu, Radu
• Format: Conference Proceeding
• Language: English
• Published: IEEE 29.11.2022
• Subjects: Accelerated aging; aging; alternators; electric field; Epoxy resins; Insulation; insulation systems; lifetime; Resistance; Stator windings; Temperature; Temperature measurement
• ISSN: 2642-5513
• DOI: 10.1109/ICEMS56177.2022.9982956

This paper presents a quick method for determining the lifetime of car alternators by performing a single accelerated aging test in the laboratory at the highest temperature indicated by IEC 60216-1 and the experimental determination (by DSC) of the activation energy. Insulation resistance was used as a diagnostic factor for aging, and as an end-of-life criterion - reduction of insulation resistance by one or two orders of magnitude. The results obtained from the tests performed on the stators of three alternators used for Logan cars, insulated with Nomex paper and epoxy resin. Accelerated aging was performed at 235 °C for 1536 h, and the insulation resistance was measured at 3-day intervals. The parameters of the lifetime line were determined and, then, the values of the estimated lifetimes for an operation at 100 degrees Celsius and of the consumed lifetimes for different time variations of the insulation temperature (different curves T(t). It is found that an increase in the temperature of the insulation causes an increase in the consumed lifetime and a decrease in the remaining lifetime. Finally, it is shown that the use of the activation energy method is less expensive than the three-temperature method, and the results are obtained much faster and it is emphasized that this method is very useful, especially when replacing insulation materials with new ones.