Patent ID: 8353676

Claim:
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 motor determining an electrical power of the motor, and a pump having at least two changing hydraulic variables; providing an electrical detection means for detecting the electrical variables of the motor; providing a hydraulic detection means for detecting the changing hydraulic variables of the pump; detecting the electrical variables of the motor with the electrical detection means; detecting the hydraulic variables of the pump 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 motor; generating the motor value by input of the detected electrical variables of the 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 variables of the pump; generating the pump comparison value by input of the motor value and the detected hydraulic variables of the pump into the mathematical mechanical-hydraulic pump model; providing a predefined pump value; comparing the pump comparison value to the predefined pump value to detect an agreement or a difference between the pump comparison value and the predefined pump value; and generating an error signal upon determining a fault based on 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 two electrical variables of the motor which determine the electrical power of the motor, are a voltage prevailing at the motor and a current feeding the motor; and the two detected hydraulic variables are each one of a pressure produced by the pump, a delivery quantity of the pump and a differential pressure between a suction side and a pressure side of the pump.