Danfoss VLT AQUA Programming Manual

Also see for vlt aqua: Instructions Design guide Instruction manual Operating instructions Design guide

Contents

Example 1: Speed at System Design Working Point is known:From the data sheet showing characteristics for the specificequipment at different speeds, simply reading across from theHDESIGN point and the Q DESIGN point allows us to find point A,which is the System Design Working Point. The pump charac-teristics at this point should be identified and the associatedspeed programmed. Closing the valves and adjusting the speeduntil HMIN has been achieved allows the speed at the no flowpoint to be identified.Adjustment of par. 22-81 Square-Linear Curve Approximationthen allows the shape of the control curve to be adjusted infin-itely.Example 2:Speed at System Design Working Point is not known: Where theSpeed at System Design Working Point is unknown, anotherreference point on the control curve needs to be determined bymeans of the data sheet. By looking at the curve for the ratedspeed and plotting the design pressure (HDESIGN , Point C) theflow at that pressure QRATED can be determined. Similarly, byplotting the design flow (Q DESIGN , Point D). the pressure HD atthat flow can be determined. Knowing these two points on thepump curve, along with HMIN as described above, allows thefrequency converter to calculate the reference point B and thusto plot the control curve which will also include the System de-sign Working Point A.VLT ® AQUA Drive Programming Guide 2. Parameter DescriptionMG.20.O2.02 - VLT ® is a registered Danfoss trademark 2092