BACKUP BEARING TEST BENCH UPGRADE AND EVALUATION

Safety of the machines and evaluation of backup systems is fundamental for the industry to develop a secure environment for the employee and ensure that components do not get damaged in case of a failure. Having the possibility to test the behavior of a bearing under the extreme stress of a simulated failure scenario is an important capability that allows to practically test these complex components. The test bench aims to characterize the behavior of the shaft when drop down at high speed on a backup bearing set. The machine was developed and designed to have a high rpm speed of test and quick maintenance and calibration. The aim of the study was to start on the solid design previously done and improve it to extend its capabilities and to fix some of the calibration and operational problems that became evident with time. The system was designed to withstand rpm up to 28’000, and the screw positioning system was fixed to obtain that. The vibration during acceleration were quite large, in the order of the hundreds of µm, and now thanks to the screw system and the lower holder plate modification are reduced in the order of the tens of µm. As a further expansion of the capabilities, a measurement system for the temperature was added on one side of the machine to record the temperature on the outer ring of the bearing. The main result was that the machine now is capable of reliably perform the tests without interruption and with no need of recalibration between each test. The centering remains stable through the measurement runs. The temperature measurement system is set up and ready to record data. Some initial test showed an interesting gradient of temperature in time toward the higher part of the bearing, exactly on the opposite side of where the shaft is dropped.