You've probably modeled pumps using curve data from the manufacturer. In conjunction with specifying a name reflecting the pump make and model and saving pumps to your component database, selecting and using these pump junctions in your system models is fast and easy. Often, however, a make/model pump will have not one set of head/pressure, efficiency and NPSHR curves, but a family of curves for various operating speeds and impeller diameters. You could define a pump junction for each set of curves, but with Multiple Pump Configurations, you can readily save the entire family of curves in one pump junction.
For simplicity's sake we'll refer to pumps here, but this tip works equally well for both pumps in AFT Fathom, AFT Mercury and AFT Impulse, and compressors/fans in AFT Arrow.
Let's first review how you model pump curves for one combination of speed and impeller diameter.
Looking at the upper lefthand corner of the Pump Configuration window you'll see two options; "Simple (configuration)", the default, and "Multiple Configurations". Selecting Multiple Configurations the Pump Configuration window will expand, revealing an area describing the configurations that have been defined.
A pump configuration is a set of curves describing the pump performance for a specific speed and impeller diameter (i.e. head/pressure and, optionally, efficiency and NPSHR). Configurations defined are listed by RPM and impeller diameter.
Let's say you want to enter the curves for 1750 RPM using 6" and 8" impellers and 3550 RPM using 4" and 5" impellers.
Repeat the above for the two 3550 RPM impeller sizes and you'll see all four configurations listed in the 'Pump Configurations Defined' area.
With multiple configurations defined, you'll now see 'RPM' and 'Impeller' drop down lists in the pump specifications window containing all the configurations defined. Changing from one set of pump curves to another is as fast and easy as selecting the desired speed and diameter from these lists.
Multiple pump configurations let you effectively model an entire family of curves in one pump junction. Coupled with the ability to store pumps in the Component Database, one can easily build and share a comprehensive database of the pumps you use.