| 摘要 |
A low volume submersible pump assembly has features to stabilize the operation. The pump assembly includes a centrifugal pump driven by a submerged electrical motor. The centrifugal pump has an impeller configuration that is designed for high specific head, but potentially unstable operation. At the design speed, the pump potentially could deliver an indeterminate flow rate for a given head. Also, at the design speed, the design flow rate will yield a design head that is very close to the maximum head at zero flow. The pump has the characteristic of requiring a significant increase in torque to produce higher flow rates. To stabilize the potentially unstable pump, a variable speed drive varies the speed of the motor to maintain constant torque. Maintaining a constant torque allows a considerable variance in head with only a small variance in flow rate resulting.
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