Simpler calculation of optimized operation for the same type variable frequency pumps in parallel

 Analyses the variation range of flow rate and speed for a pump in efficient working. For the distribution system equipped with a number of the same type variable frequency pumps in parallel, presents the simpler calculation method of operated number and frequency of pumps on the condition of required water flow rate and minimum shaft power. The result of an example shows that the pump operation can be optimized with the method.