Brochure

3131
In addition to head, the power consumption (P) is also to be found in the data
sheet. The power consumption is used for dimensioning of the installations
which must supply the pump with energy. The power consumption is like
the head shown as a function of the flow.
Information about the pump eciency (η) and NPSH can also be found in
the data sheet. NPSH is an abbreviation for ’Net Positive Suction Head’. The
NPSH curve shows the need for inlet head, and which requirements the
specific system have to fullfill to avoid cavitation. The eciency curve is
used for choosing the most ecient pump in the specified operating range.
Figure 2.1 shows an example of performance curves in a data sheet.
During design of a new pump, the desired performance curves are a vital
part of the design specifications. Similar curves for axial and radial thrust are
used for dimensioning the bearing system.
The performance curves describe the performance for the complete pump
unit, see figure 2.2. An adequate standard motor can be mounted on the
pump if a pump without motor is chosen. Performance curves can be
recalculated with the motor in question when it is chosen.
For pumps sold both with and without a motor, only curves for the hydraulic
components are shown, i.e. without motor and controller. For integrated
products, the pump curves for the complete product are shown.
Motor Controller
Coupling
Hydraulics
Figure 2.2.: The performance curves are
stated for the pump itself or for the
complete unit consisting of pump, motor
and electronics.