Patent ID: 8680793

Claim:
A machine, comprising: a rotor, a converter-controlled drive with a variable rotational frequency, a working machine, wherein the drive and the working machine are connected to one another such that a torque is transmitted, a frequency converter which is electrically connected to the drive and converts input frequencies to output frequencies, wherein the frequency converter is embodied such that in a Campbell diagram, relating to the machine, intersection points result from the natural torsional frequency of the rotor and V-shaped symmetrical straight lines of the inter-harmonic exciter frequency for the output frequencies, wherein the output frequencies are grouped into a plurality of concentration ranges based upon a rotational speed of the machine, wherein each concentration range comprises output frequencies which are close to one another and which respectively have a common output point on the abscissa of the Campbell diagram, wherein upper and lower limits of each concentration range is defined by an intersection point of a lowest and/or second lowest and/or third lowest natural torsional frequency of the rotor and two straight lines of a pair of the inter-harmonics of the first order of the concentration range, wherein each concentration range defines a blocking range, and wherein the machine has an operating rotational speed range which lies outside the blocking ranges.