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This is the common data usually specified for positive displacement pumps. Complete characterisation of the model requires such data sets for several operating voltages.

It is unfortunately a common practice to specify such a data set for only one "nominal" voltage. This is of course not suitable for computing direct-coupled configurations. The extension to other voltages requires a strong hypothesis, which is (in this first status of the model) that the Pump Efficiency is constant when varying the voltage. The figure shows an example of measured efficiency profile. We can observe that within the reasonable operating range 30-64V, the variations are of the order of 15%

 

If we 2 voltage curves are available, the efficiency figure is a linear interpolation, which improves the model's accuracy.

Given  Pp and  FR as f(Head) for fixed Voltage

This is equivalent to the preceding scheme, as for each data point the current may be easily determined from power, using the fixed voltage parameter of the curve.