Selection of preset parameters to assess the compliance of restored submersible electric motors with the overhaul requirements

The main characteristic of the performance of submersible electric motors after overhauls is their reliability. To assess the compliance of reliability indicators of restored submersible electric motors with technical requirements for overhauls, various types of tests are used. The most acceptable of them is the bench test method based on a sequential failure analysis of the studied electric motors. To implement it, the specified parameters should be set. In this study, based on the use of technical requirements for the manufacture and repair of submersible electric motors, the authors determined the specified average operating times for failure of new electric motors (before the first overhaul) and after it. Bench tests were carried out for two batches of submersible electric motors: overhauled and non-overhauled. In each batch, 20 electric motors were studied. The experiment determined the standard deviation of the mean time between failures (MTBF) of new electric motors, which amounted to 3.54 thousand hours, after the overhaul – 2.37 thousand hours. The coefficients of variation were 0.3 and 0.34, respectively. The study results determined the values of the set parameters of the mathematical model, enabling the use of the method of successive failure analysis. The values included the set average MTBF before the first overhaul – 16 thousand hours; the set average MTBF after the overhaul – 12.8 thousand hours; the risks of the repair provider and the customer – 0.05; the set mean square deviation of the MTBF of electric motors before the first overhaul – 4.8 thousand hours; the set mean square deviation of the MTBF after the first overhaul – 4.8 thousand hours; the set mean square deviation of the MTBF after the overhaul – 2.37 thousand hours.

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