Abstract
In this paper, a small centrifugal pump experiment was conducted under conditions of power frequency startup and frequency conversion startup respectively. The evolutionary trends for hydraulic performance parameters with time were obtained, and the transient properties of the two starting modes were revealed with the help of three dimensionless coefficients. This study revealed the similarities and differences between the two starting modes. In both starting modes, the increase of the valve opening caused a time lag for the flow to reach a steady state. Compared with the power frequency startup mode, the frequency conversion startup mode had weaker shaft power shocks and was safer in practice. The dimensionless flow curves maintained a good evolutionary agreement with the corresponding flow curves. The dimensionless shaft power was extremely high at the beginning of startup and then decreased to a stable value.