Patent ID: 8763464
Filing Date: 2014-07-01
Classification: F04D

Abstract:
1. A method for determining an operating point of a work machine or of an asynchronous motor driving the such a machine, wherein the operating point is characterized by a power input of the work machine or by a delivery rate of the work machine; one or more operating point-dependent measurement variables of the work machine are detected by one or more sensors; measured values of the variables are evaluated or stored while the work machine is in operation; and the operating point is determined without the use of electrical measurement variables of the asynchronous drive motor; said method comprising: determining a frequency linearly proportional to the rotational sound of the work machine by signal analysis of a measured mechanical variable selected from the group consisting of pressure, differential pressure, force, vibration, solid-borne noise, and airborne noise; determining the rotational speed (n) of the drive machine from said frequency; and determining the operating point from the slip-induced rotational speed/torque dependence of the asynchronous motor.