## 4 Results  
### Dataset  
The Ottawa University rolling bearing dataset [38], known as the UORED-VAFCLS (vibration and acoustic fault characteristics under constant load and speed), is collected under constant load and speed conditions using a test bench, referred to as the Ottawa dataset. This dataset includes vibration and acoustic fault characteristic data for rolling element bearings operating under stable nominal rotational speeds and loads. Each group of raw data is obtained at these constant conditions, as shown in Figure 3.  
The dataset covers four different failure types: inner raceway, outer raceway, ball, and cage, with five instances of each failure type. The Ottawa dataset is dedicated to the 6203 deep groove ball bearing with a sampling frequency of 48 kHz. The collected data consist of both vibration signal data and acoustic signal data. The parameters of the selected bearing dataset are shown in the following Table 2.  
In addition to utilizing the Ottawa bearing dataset, experimental data obtained from the Pade bearing test bed at the University of Paderborn was adopted for the performance validation process [39]. As shown in Figure 4, the Pade bearing test bench consists of a motor, a torque measuring shaft, a rolling bearing test module, a flywheel, and a load motor. In order to effectively monitor the operational status of the bearings, the dataset  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Bearing Code** & **Bearing Name** & **Damage Level** & **Class** & **Characteristic of Damage** \\ \hline H-1-0 & H1 & No damage & H & Single point \\ \hline I-1-2 & IR1 & No damage & IR & Single point \\ \hline
0-6-2 & OR1 &
\begin{tabular}{c} Plasticedform; \\ indentations \\ \end{tabular} & OR & Single point \\ \hline B-11-2 & B1 & Fatigue; pitting & B & Single point \\ \hline C-16-2 & C1 & Plasticedform & C & Single point \\ \hline \hline \end{tabular}
\end{table}
Table 2: Operating parameters of Ottawa bearings.  
Figure 3: UORED-VAFCLS test stand in operation: (**a**) front view; (**b**) side view.  
was comprehensively evaluated by measuring the phase currents of the drive motor, as well as the acceleration of the bearing housing. In this experiment, the test bearing used was a model 6203, whose operating parameters included a shaft speed of 1500 r/min, a radial force of 1000 N, and a load torque of 0.7 N m, all of which were kept constant.  
The bearing measurements contained in the Pade dataset are classified into three main categories: normal, inner raceway failures, and outer raceway failures. Further, depending on the degree of damage caused by the faults, it is possible to categorize these faults into two classes: the first class is for those cases where the damage is minor, i.e., those where the damage diameter is less than 2 mm; the second class covers faults where the damage diameter is between 2 mm and 4.5 mm. In addition, the raw accelerometer measurements were taken at a high sampling frequency of 64 kHz.  
In this study, we use the fault classification data from this bearing dataset to validate model performance. Vibration and current data from eight bearings, coded as K001, KA01, KI01, etc., are selected for the dataset. The parameters of the selected bearing dataset are shown in the following Table 3