Synthesized Synchronous Sampling Technique for Differential Bearing Damage Detection

Abstract

The differential bearing between the low-pressure turbine (LPT) and high-pressure turbine (HPT) shafts is one of the most vulnerable parts in a turbomachinery engine. Unfortunately, it is also one of the most difficult parts to monitor for damage existence signatures, because the signal-to-noise ratio at the normal sensor locations is extremely low. In addition, the speed variations in both the LPT and HPT can further deteriorate the damage signature extracted by conventional analysis methods. In this paper, we developed a “synthesized synchronous sampling” technique to enhance the detection of differential bearing damage signature. Combining this technique together with the conventional acceleration enveloping technique, we are able to detect differential bearing damage at a much earlier stage, thus providing early warnings of the machinery health conditions.