## 3 Centralized Lubrication and Waste Grease Recovery Test Platform Test
### Vacuum Degree Test
#### 3.1.2 Power Oil Pressure Test of the Grease Suction and Drainer Device  
The oil supply pump provides the working power for the suction and discharge devices. port A and port B are the two connecting ends of the power lines of the suction and drainer device. In order to check whether the working power of the active waste oil recovery device is reliable, power oil pressure tests were performed on the grease suction and drainer devices to test the power oil pressure changes of the grease suction and drainer devices after 12,000 fatigue tests. The test results of the power oil pressure are presented in Figure 9.  
Figure 8: 0.07 MPa oil output speed distribution (a); 0.08 MPa oil output speed distribution (b); 0.09 MPa oil output speed distribution (c). Figure 9: Power oil pressure of the grease suction and drainer devices after 12,000 fatigue tests. In order to verify the reliability of the measured power oil pressure of the grease suction and drainer devices, descriptive statistical analysis was performed based on the test data of Figure 9. The results of the calculations are presented in Table 2.  
Table 2 shows the results of the descriptive statistics of the power oil pressure after the 12,000 fatigue tests, including statistics such as sample size, maximum value and minimum value, which are used to study the overall situation of the power oil pressure. The absolute value of kurtosis of port A and port B is less than 10, and the absolute value of skewness of port A and port B is less than 3, so the power oil pressure essentially follows a normal distribution. The coefficient of variation (CV) of port A is 0.064, and there is a small probability of abnormal value (CV < 0.15) in the power oil pressure data of port A. In 39 groups of tests, the average value is used to represent the power oil pressure of port A, which is 4.75 MPa. The coefficient of variation (CV) of port B is 0.026. There is a small probability of an abnormal value (CV < 0.15) in the power oil pressure data of port B. The average value is used to represent the power oil pressure of port B, which is 5.03 MPa. After calculation, the uncertainty of the power oil pressure of port A is 0.35, and the uncertainty of the power oil pressure of port B is 0.36, indicating that the measurement results of the power oil pressure in the 12,000 fatigue tests of the grease suction and drainer devices are highly reliable. As can be seen from the coefficient of variation of the above power oil pressure, the coefficient of variation is less than 0.15, which indicates a small probability of occurrence of outliers, and the degree of dispersion is small, indicating that the power oil pressure of the grease suction and drainer devices is stable. It can be seen from Figure 10 and Table 2 that the power oil output from the fuel pump maintains a stable oil pressure at the inlet and outlet of the grease suction and drainer devices. The pressure of the hydraulic system is determined by the load, and port A and port B should ideally have equal pressure. To meet the practical work requirements of the grease suction and drainer devices, this study aims to set the oil supply pump after a single suction to continuously supply power to ensure a smooth discharge process. Therefore, the pressure difference between port A and port B is a reasonable design. The pressure of the power oil at port A and B was 4.75 MPa and 5.03 MPa, respectively, indicating that the operating pressure of the power oil pipe in the grease suction and drainer devices met the test requirements. After 12,000 cycles, the power oil pressure output by the oil supply pump was stable and meets the test standards, indicating that the oil supply pump can provide stable power for operation of the grease suction and drainer devices and meet the power demand of the wind power waste oil recovery system.