# Investigation of Failure Causes of Oil Pump Based on Operating Conditions
## 4 Test Bed  
Acquiring the actual data of the normal and abnormal components of the pump would take considerable time and would be expensive. Instead, a test bed was established to implement each major failure characteristic and acquire data considering the operating environments of the parts of the pump. Figure 2 shows the test bed for collecting normal and abnormal data from the parts of the pump. As shown in the figure, the test bed on land was built as an individual system, unlike the multi-connected system configuration, to monitor the pump's functional parts [21]. Table 4 presents the measurement ranges, error ranges, and sampling rate information for sensors installed on the equipment, such as the flowmeter, pressure gauge, thermometer, and accelerometer. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Module** & **Function** & **Component** & **Failure Mode** & **Failure Mechanism** \\ \hline Pump & Reduction of friction of components having relative motion with parts & Bearing & Wear & 6-1 & Surface cracking and misalignment due to vibration \\ Pump & Contamination, pressure and leakage protection & Sealing & Leakage & 7-1 & Overload and overheating \\ Pump & Motor and pump shaft connection & Coupling & Elastomer wear & 8-1 & Misalignment, bearing \\  & & & Noise and vibration & 8-2 & damage, overload \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._ \begin{table}
\begin{tabular}{c c c} \hline \hline
**Failure Part** & \multicolumn{2}{c}{**Failure Mode**} \\ \multicolumn{2}{c}{**Name**} & \multicolumn{2}{c}{**Mechanism**} \\ \hline Bearing & Poor lubrication & Poor lubrication-based adhesion and foreign substance-based wear \\ Coupling & Misalignment & Crack caused by angle, parallel, and lateral changes \\  & Elastomer wear & & Deferation of elastomer \\ Sealing & Temperature aging & Degradation of material properties due to thermal aging \\ Screw & Cavitation & Corrosion and wear due to pressure changes \\  & Contamination & Surface wear caused by fluid contamination \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Failure modes and mechanisms of each pump part. The pump test bed is designed to control normal and abnormal characteristics precisely. In line with the advice of the manufacturer, the test facility was optimized and upgraded to verify its suitability for the test. More specifically, the piping design conditions were optimized to stably implement the operating conditions (flow rate, etc.) of the target device by performing a preliminary operation. In addition, uncertainty-inducing factors, such as cavitation, that could affect the operating environment were eliminated to accurately control and measure the flow rates. Using the installed sensors, the database was obtained considering environmental parameters such as temperature and pressure flow. In addition, the additional failure response for vibration and noise was acquired. The data were collected and stored in CSV data files through simultaneous modules such as the DAQ Card module and Sinus Apollo Light module [22]. Table 5 presents information about the manufacturer and operating conditions of the pump test bed. The test bed was prepared using a screw pump (KRAL company), which is commonly used in ships. Then, a trial test was conducted to confirm whether the performance and safety of the equipment were secured and whether the operating environment could be reproduced. Fault test diagnostic data acquisition and system control software was configured to enable monitoring of driving data 16 CH and vibration characteristic data 8 ch. In addition, the operation of the development SW enabled real-time analysis of acquisition signals, such as the acquisition of failure diagnostic data for each failure scenario and FFT analysis. Vibration data were used in real-time monitoring of high frequency bands using Amadeus software (FAMTECH), and the application of the condition-based monitoring system was verified by comparing data using the development software. The test was conducted three times for 900 s.