## 3 Experimental Test Bed
### Centrifugal Pump Test Bed  
The experiments were performed over a vertical ten-stage centrifugal catalog number 3 SV10 TE4F60 driven by a two-hp induction motor that provides rotatory motion at 3500 rpm. The technical specifications are presented in Table 1. The main parts of the vertical centrifugal pump test bench are shown in Figure 3, while Figure 4 shows the sensor placements.  
The vertical multi-stage centrifugal pump test bench includes sensors for simultaneously acquiring several signal types. Specifically, the test bench includes three sensors for acquiring each of the three-phase currents used for feeding the motor (CV1, CV2, CV3), four accelerometer sensors (A1, A2, A3, A4), two acoustic emission sensors (AE1, AE2), two microphone sensors for recording the acoustic sounds (Mic1, Mic2), one sensor corresponding to an incremental encoder (E1), two pressure sensors (P1, P2) and one flow sensor (C1). Although the dataset includes all the sensors recorded, only the accelerometer signals are considered in this research.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Technical Specification** & **Value** & **Technical Specification** & **Value** \\ \hline Brand & Goulds & No. of stages & 10 \\ Model & 3 SV10 TE4F60 & Nominal flow & 15 GPM \\ Type & Centrifugal axial flow-vertical axis & Flow range & (3-2) GPM \\ Power & 2 HP & Maximum head & 1085 RH \\ Motor power & Three-phases 208–230/460 V & Maximum operating pressure & 580 PSIG \\ Motor speed & 3500 rpm & Discharge pressure & 10.7 BAR \\ Type of transmission & Aluminum coupling & Pump efficiency & 60 \\ \hline \end{tabular}
\end{table}
Table 1: Technical specification of the centrifugal pump 3 SV10 TE4F60.  
The experimental test bed enables the configuration of several impeller faults with eight or six levels of severity. In particular, the dataset includes five conditions:  
* healthy condition (Healthy),
* pitting at the entrance of the impeller blades (PEB),
* pitting at the output of the impeller blades (POB),
* impeller channel blockade (ICB),
* imbalance impeller (IB).  
In faults, PEB, and POB, the eight levels of pitting severity are simulated by holes in the blades with a diameter size and a number of holes that are increased according to the severity level. This condition is created with Electrical Discharge Machining (EDM). Similarly, six levels of severity for ICB are attained by closing the different channels of the impeller. The six levels of severity for the impeller imbalance fault are simulated by cutting portions of the impeller with increasing area.  
Figure 4: Centrifugal pump test bench with an indication of the sensor’s location. The accelerator sensors are A1, A2, A3, and A4. The pressure sensors are P1 and P2. The current sensors are CV1, CV2, and CV3. The acoustic emission sensors are AE1 and AE2. The acoustic sound signals are recorded with sensors Mic1 and Mic2. In addition, a rotary encoder sensor is E1, and C1 is a flow sensor. Only the vibration signals acquired with the accelerometers are considered in this research.  
Figure 3: Centrifugal pump test bench. The vertical centrifugal pump (model 3 SV10 TE4F60) has ten stages. Each stage has an impeller with the corresponding cover, and all the impellers are connected to the motor through a vertical shaft and a coupling system.  
The faulty conditions in the multi-stage centrifugal pump correspond to 13 conditions labeled _P1_-_P13_. Each condition is one of the five conditions previously described for the impellers. The severity of each faulty condition increases according to the stage and the type of condition. The fault combinations are presented in Table 2. The number in columns for stages 5 to 10 represents the severity of the faulty condition presented in the second column.