# Software for Monitoring the In-Service Efficiency of Hydraulic Pumps
## 5 Assessment of a Pump's In Situ Operating Conditions Using the Software Module  
The software module has been implemented at AQUATIM S.A. to monitor the operation of the double suction Worthington 500 LNN-775A double suction pumps of 1 MW, that supply Timisoara city with drinkable water. The experimental data determined at the speed of 993 rpm by the manufacturer of the 1 MW double suction pump, installed at AQUATIM S.A., is listed in Table 6 and is marked with black dots (\(\bullet\)) in Figure 17. Application of the algorithm presented in Section 2 has allowed the determination of the approximation polynomials' coefficients, which are shown in Table 7 for \(H=f(Q)\), Table 8 for \(P_{m}=f(Q)\) and Table 9 for \(\eta_{P}=f(Q)\) and marked with continuous lines in  
Figure 18 shows the curve of the pumping head (\(H(Q)\)) of the Worthington 500 LNN-775A double suction pump of 1 MW, installed at AQUATIM S.A., at the speed of 993 rpm (continuous red line), determined based on the experimental data provided by the manufacturer. The curve for hydraulic losses (\(H_{r}(Q)\)) of the Timisoara city supply network (continuous blue line) is determined based on experimental data ( in Figure 18) obtained in situ. The duty point (DP, marked with a red circle (\(\Circle\)) of this pump was determined to be at the intersection of the two curves \(H(Q)\) and \(H_{r}(Q)\). The input parameters for the Worthington 500 LNN-775A double suction pump of 1 MW, installed at AQUATIM S.A., read by the software module are: the suction line diameter \(D_{s}=0.6\,m\), and the discharge line diameter \(D_{d}=0.5\,\mathrm{m}\). The instruments are installed on the pump flanges, meaning that \(l_{s}=l_{d}=0\,\mathrm{m}\) and the level difference between the location of the instruments installed on the discharge and suction flanges \(\Delta z=0.6\,\mathrm{m}\). The hydraulic loss coefficients, distributed for the suction lines \(\lambda_{s}\) and discharge lines \(\lambda_{d}\) \begin{table}
\begin{tabular}{c c c c c} \hline \(n\) [rpm] & \(h_{0}\) & \(h_{1}\) & \(h_{2}\) & \(R^{2}\) \\ \hline
993 & 80.499 & 2.347 & \(-12.338\) & 0.995 \\ \hline \end{tabular}
\end{table} 
Table 7: The coefficients of the 2 nd-degree polynomial approximation function for the pumping head \(H=f(Q)\) of the 1 MW Worthington pump at speed of 993 rpm. \begin{table}
\begin{tabular}{c c c c c} \hline \(n\) [rpm] & \(e_{0}\) & \(e_{1}\) & \(e_{2}\) & \(R^{2}\) \\ \hline
993 & 1.056 & 137.427 & \(-50.908\) & 0.997 \\ \hline \end{tabular}
\end{table} 
Table 8: The coefficients of the 3 rd-degree polynomial approximation function for the mechanical power \(P_{m}=f(Q)\) of the 1 MW Worthington pump at speed of 993 rpm. Figure 18: The duty point (DP) of a Worthington 500 LNN-775A double suction pump of 1 MW at speed of 993 rpm operating in Timisoara drinking water network. are not relevant in this case because the instruments are installed on the flanges, and the local hydraulic loss coefficients for the suction and discharge lines \(\zeta_{s}=\zeta_{d}=0\) because no elbow was installed in the pump suction or discharge. In this case, the pumping head is computed using the simplified formula presented in Equation (2) instead of the generalized formula presented in Equation (3). The variable speed drive for Worthington 500 LNN-775A double suction pump includes an ACS 800-7 1000 kW DTC closed-loop speed inverter [37], but no torque transducer is installed in situ. This DTC inverter is manufactured by the same company as the one installed in the \"Politehnica\" University laboratory [34]. Both DTC inverters have the same torque and speed control performances [34; 37]. In these conditions, the total uncertainty for the mechanical power is determined using the accuracy of \(\pm 4\%\) with nominal torque in an open loop and the speed control in a closed loop with an accuracy of 0.01% from the nominal speed. As a result, a total uncertainty of over \(\pm 4\%\) is predicted for the pump efficiency under in situ conditions.