Control device for membrane pump for loading filter press

摘要

Has motor supplied by variable frequency converter from mains operating in analogue fashion, plus speed and speed set point controllers.- DETAILED DESCRIPTION - A control device has an electric drive motor (16) for the pump (18) which is connected via a frequency converter (20) of variable frequency to the supply network, the frequency converter having an analogue regulating input and an analogue output where an actual-value signal corresponding to the motor torque appears. A speed controller (26) to which the actual-value signal is given via an inverter (28) and a speed set point controller (30) to one input of which is given the output of the speed controller and to the second input is given a selected maximum speed set point value so that the output signal of the set point controller is determined by the maximum speed value until the output of the speed controller reaches a specified value and then runs along a falling curve (stored in the set point controller) down to a minimum value, the curve corresponding to a selected variation of speed according to load pressure