Machine having a converter controlled drive

1. 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 output frequencies are grouped into a plurality of concentration ranges based upon a rotational speed of the machine,

wherein each concentration range defines a blocking range, and

wherein the machine has an operating rotational speed range which lies outside the blocking ranges.

2. The machine as claimed in claim 1 , 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.

3. The machine as claimed in claim 2 , 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.

4. The machine as claimed in claim 3 , 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.

5. The machine as claimed in claim 1 , wherein the drive comprises a plurality of pole pairs which, together with a motor feeding frequency range, define the operating rotational speed range which lies outside the blocking ranges.

6. The machine as claimed in claim 1 , wherein a transmission for transmitting the rotational speed of the drive to a rotational speed of the working machine acts between the drive and the working machine.

7. The machine as claimed in claim 6 , wherein the rotational speed of the working machine is higher than the rotational speed of the drive.

8. The machine as claimed in claim 1 , wherein the frequency converter is a current intermediate-circuit converter.

9. The machine as claimed in claim 1 , wherein the frequency converter is a voltage converter.

10. The machine as claimed in claim 1 , wherein the drive is a synchronous motor.

11. The machine as claimed in claim 1 , wherein the drive is an asynchronous motor.

12. The machine as claimed in claim 1 , wherein a maximum absorption capacity of the drive is at least one megawatt.

13. The machine as claimed in claim 1 , wherein the working machine is a turbo-machine.

14. The machine as claimed in claim 1 , wherein the working machine is a turbo compressor.

15. A method of operating a machine with a rotor, comprising:

providing a converter-controlled drive with a variable rotational frequency and a working machine,

connecting the drive and the working machine such that a torque is transmitted,

connecting electrically a frequency converter to the drive, wherein the converter converts input frequencies to 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 defines a blocking range, and

wherein the machine has an operating rotational speed range which lies outside the blocking ranges.