초록 ▼

A variable-speed submersible pump has a centrifugal pump, with a grinder for entrained solids at the intake, driven by a variable-speed 3-phase AC motor. A microcontroller controls the pump output on the basis of sensor data and/or inputs from an external controller, and also monitors the operation

A variable-speed submersible pump has a centrifugal pump, with a grinder for entrained solids at the intake, driven by a variable-speed 3-phase AC motor. A microcontroller controls the pump output on the basis of sensor data and/or inputs from an external controller, and also monitors the operation of the pump unit and emits alarms and statistical reports as appropriate. If the pump is clogged, the controller attempts to free it, firstly by reducing the pump speed and increasing the torque, secondly by jogging the pump backwards, and thirdly by running the pump briefly at maximum speed. Before pumping starts, and at intervals when the tank in which the pump is submerged is not full enough to be worth emptying, the pump is run backwards. That serves to agitate the tank, re-suspend any solids content that may tend to settle out in the tank, and thus improve pumping of the solids with the liquid. When the pump is pumping normally, it starts at a preset speed, and the pump speed may be increased in steps until a desired rate of pumping is achieved or until the maximum speed of the pump is reached.

대표청구항 ▼

1. A method of operating a variable-speed pump driven by a motor capable of developing high torque at low speeds, comprising the steps of:running the pump at a first selected speed; determining whether the pump is clogged by assessing the torque being generated by the motor; when the torque being de

1. A method of operating a variable-speed pump driven by a motor capable of developing high torque at low speeds, comprising the steps of:running the pump at a first selected speed; determining whether the pump is clogged by assessing the torque being generated by the motor; when the torque being developed by the motor exceeds a maximum for the selected speed, reducing the selected speed of the pump and thereby increasing the maximum acceptable torque for the motor; determining whether the pump is still clogged by assessing the torque being generated by the motor; when the torque exceeds said increased maximum acceptable torque for the newly selected speed, repeating the steps of reducing the speed and assessing the torque; and at any point when it is determined that the pump is no longer clogged, resuming pumping at said first selected speed.