Patent ID: 8070457
Filing Date: 2011-12-06
Classification: F04D

Abstract:
1. A method for determining faults on operation of a pump assembly, the method comprising the steps of: providing the pump assembly with a pump motor with at least two electrical variables of the pump motor determining the electrical power of the pump motor, and the pump assembly having at least one changing hydraulic variable of the pump assembly; providing an electrical detection means for detecting the electrical variables of the pump motor; providing a hydraulic detection means for detecting the changing hydraulic variable of the pump assembly; detecting the electrical variables of the pump motor with the electrical detection means; detecting the hydraulic variable of the pump assembly with the hydraulic detection means; providing a mathematical electrical motor model for generating a motor value from a mathematical linking of the detected electrical variables of the pump motor; generating the pump motor value by input of the detected electrical variables of the pump motor into the mathematical electrical motor model; providing a mathematical mechanical-hydraulic pump model for generating a pump comparison value from a mathematical linking of the motor value and the detected hydraulic variable of the pump assembly; generating the pump comparison value by input of the motor value and the detected hydraulic variable of the pump assembly into the mathematical mechanical-hydraulic pump model; providing a predefined pump value; comparing the pump comparison value to the predefined pump value to detect agreement or a difference between the pump comparison value and the predefined pump value; and generating an error signal upon detecting a difference between the pump comparison value and the predefined pump value beyond a threshold to indicate a faulty function of the pump, wherein the electrical motor model is formed by the following equations: or or in which i i Ψ Ψ T ν ν ω is an angular speed of the rotor and an impeller or the actual rotor and impeller rotational speed R′ R′ L L′ L z I V ω Z Z R R L wherein d and q are two directions perpendicular to a pump motor shaft and perpendicular to one another and wherein the mechanical-hydraulic pump model is formed by the equation: and at least one of the equations: in which is a temporal derivative of an angular speed of the rotor, T J is a moment of inertia of the rotor, impeller and a delivery fluid contained in the impeller, B is a friction constant, Q is a delivery flow of the pump assembly, H a a