摘要 |
A multi-stage concentric centrifugal pump includes a start stage. An inner impeller stage is driven by drive shaft while an electric motor drive is selectively switched on for starting, and off for normal operation to drive an outer impeller stage. The electric motor driven outer stage builds required system pressure and flow at engine starting, and then permits the electric motor to be switched off and allow the outer stage to. act as a free rotating disk to improve operating efficiency of the pump.
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