Health Condition Monitoring of Ball Bearings Test Bench Under Running Conditions Using A Mems Accelerometer

Abstract

Background: Rolling-bearing faults are best caught while the machine is running, yet instruments that do this are costly. This experiment work reports the condition monitoring of ball bearings under running conditions with a low-cost ADXL335 MEMS accelerometer, and an indigenous impulse-excitation test bench for checking bearings at rest.

Methods: In the running-condition tests, a 6300-series bearing was run in five health states (healthy, inner-race fault, outer-race fault, combined inner–outer fault and combined cage–ball fault) at 1000, 1250 and 1500 RPM under 15, 30 and 60 kg applied load; 30 tests of 7 min each gave 200 samples.

Results: The calculated fault frequencies range up to 107 Hz at 1500 RPM and it lie inside the sensor bandwidth. The test bench, which strikes the inner race with a solenoid-driven rubber-tipped plunger and processes the response in LabVIEW through a PSoC interface, was validated with impact measurements on four new, defect-free 6201 bearings (50 impacts each); the coefficient of variation of the impact amplitude within a bearing was 0.4–3.7 %.

Conclusion: The combined cage–ball fault was the most readily detected condition, and the low-cost MEMS chain separated healthy and faulty bearings in the time domain.