Do you know the difference between the starting characteristics of different types of pumps?

The starting of a pump or pump group is a light load start for the prime mover, and generally there will be no problems when starting. However, for some large units, due to the large inertia of the unit, it is difficult to start, and there is a large starting current when starting. If you do not pay attention to the starting method, it will damage the power grid or the motor. Therefore, the starting characteristics of different types of pumps should be given enough attention.

 

  1. Zero flow starting characteristics of centrifugal pumps-closed valve start

 

The shaft power of the centrifugal pump is the smallest at zero flow conditions, which is 30%~90% of the rated shaft power, so the starting characteristic of the centrifugal pump is zero flow start (i.e. closed valve start). The discharge valve can be adjusted to the rated flow point only after the pump reaches the rated speed.

 

  1. High flow starting characteristics of axial flow pumps-full open valve start

 

The shaft power of the axial flow pump is the largest at zero flow conditions, which is 140%~200% of the rated shaft power, and the power is the smallest at the maximum flow. Therefore, in order to minimize the starting current, the starting characteristic of the shaft power should be high flow start (i.e. full open valve start).

 

  1. Startup characteristics of mixed flow pumps – fully open valve start

 

The shaft power of mixed flow pumps at zero flow conditions is between the above two pumps, which is 100%~130% of the rated power, so the start-up characteristics of mixed flow pumps should also be between the above two pumps, and it is best to start with a fully open valve.

 

  1. Startup characteristics of vortex pumps – fully open valve start

 

The shaft power of vortex pumps is the largest at zero flow conditions, which is 130%~190% of the rated shaft power, so similar to axial flow pumps, the start-up characteristics of vortex pumps should be large flow start (i.e. fully open valve start).