| 摘要 |
A method and apparatus are provided for controlling the operation of a pump, featuring steps of sensing a no water or dead head condition of the flow of the medium in the pump, and dynamically reducing the set-point of the pressure for monitoring the flow of the medium. In operation, a no water operating condition is sensed based on some combination of the magnitude of the motor power consumption, the system pressure, the motor speed, or the flow. The test for the no water operating condition may include the following three conditions: whether the magnitude of the motor power consumption is below full load, the system pressure is below a desired operating point, and the motor-speed is at full speed. The test for the no water operating condition may also include the step of lowering the pump/motor speed and checking if the system pressure drops. If the system pressure drops, then the pump will continue to run, while if the system pressure does not drop, then no flow is detected and the pump is turned off.
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