Patent ID: 9587640
Date: 2017-03-07
CPC Classifications: F04D,G01F

Claim:
1. A method in connection with a pump driven with a frequency converter, comprising: a) measuring, in a measurement device, and storing a flow rate (Q b) storing a used rotational speed (n in the frequency converter: c) determining from a characteristic curve that is transformed into stored rotational speed (n d) calculating a bias value of the torque (T e) determining an operating point of the pump based on the bias value of the torque (T wherein the bias value of the torque is transferred with an affinity law from the rotational speed (n wherein the step of measuring and storing the flow rate comprises storing a time stamp of the measurement, and the step of storing the used rotational speed and torque comprises storing a time stamp of stored events for synchronizing the rotational speed and torque with the stored flow rate, and f) operating the pump with the frequency converter according to the determined operating point.