... - Q-H Curve of the Variable Speed Pump In figure 1, a is the Q-H curve of which the pump runs with the rated speed n0, b is the Q-H curve of which the pump runs at the speed of n1, n1=0.75n0, ... should be added to the lower limit of the speed ratio according to the pump characteristic, then d in Figure 2 is the Q-H curve of the pump at present. Therefore, the range of each variable speed ... c is the critical state of which the pump can supply water under the outlet pressure of the pump station determined after the first optimization. In the process of practical operation, the pump...