GENERATOR TEST BENCHES AND BACK-TO-BACK TESTING SYSTEMS AND METHODS

1 . A generator test bench, comprising:

(i) a fixed structure, having

a common base fixed to a ground;

a hollow body, having a first opening and a second opening;

a central pillar connecting the common base with the hollow body;

(ii) a shaft, arranged inside the hollow body, having a first end extending beyond the first opening and a second end extending beyond the second opening,

wherein the first end of the shaft is connectable to a first rotor of a first generator and the second end of the shaft is connectable to a second rotor of a second generator, and

wherein the fixed structure is connectable to stators of the first and second generators.

2 . The test bench according to claim 1 , wherein the first opening defines a first flange and the second opening defines a second flange, the first flange being connectable to the stator of the first generator and the second flange being connectable to the stator of the second generator.

3 . The test bench according to claim 2 , wherein each generator has a center and the shaft is arranged to traverse a space in the center of each generator.

4 . The test bench according to claim 1 , wherein the hollow body is at least partially cylindrical.

5 . The test bench according to claim 4 , further comprising at least one bearing inside the hollow body for coupling the shaft to the hollow body.

6 . The test bench according to claim 1 , further comprising:

a first shaft connector coupled at a first point to the first end of the shaft, and

a second shaft connector coupled at a first point to the second end of the shaft,

wherein the first and second connectors are connectable to the first and second rotors, respectively, at a second point.

7 . A back-to-back testing system comprising:

a test bench comprising:

(i) a fixed structure, having

a common base fixed to the ground;

a hollow body, having a first opening and a second opening;

a central pillar connecting the common base with the hollow body;

(ii) a shaft, arranged inside the hollow body, having a first end extending beyond the first opening and a second end extending beyond

the second opening, and

a pair of converters, each arranged to be electrically connectable to a generator,

wherein the first end of the shaft is connectable to a first rotor of a first generator and the second end of the shaft is connectable to a second rotor of a second generator, and

wherein the fixed structure is connectable to stators of the first and second generators.

8 . The back-to-back testing system according to claim 7 , wherein the converters are power electronic converters.

9 . The back-to-back testing system according to claim 7 , further comprising a controller, adapted to control at least a speed and a torque of the generators.

10 . A first generator and second generator in combination with the back-to-back testing system according to claim 7 , further comprising:

the first generator arranged in a motor configuration, the first rotor being connected to the first end of the shaft;

a slip ring for transmitting a torque of the first generator to the shaft; and

the second generator arranged in a generator configuration, the second rotor being connected to the second end of the shaft.

11 . The combination first and second generators and back-to-back testing system according to claim 10 , wherein the generators are direct-drive generators and each comprises a central space.

12 . The combination first and second generators and back-to-back testing system according to claim 10 , wherein the rotors of the generators are flexibly coupled to the shaft.

13 . A method of testing generators in a back-to-back testing system, the back-to-back testing system having a test bench and a pair of converters, the test bench comprising:

(i) a fixed structure, having

a common base fixed to the ground;

a hollow body, having a first opening and a second opening;

a central pillar connecting the common base with the hollow body; and

(ii) a shaft, arranged inside the hollow body, having a first end extending beyond the first opening and a second end extending beyond the second opening, and

a pair of converters, each arranged to be electrically connectable to a generator, the method comprising:

mounting a first generator on the test bench;

mounting a second generator on the test bench;

driving the first generator as a motor; and

testing the second generator.

14 . The method according to claim 13 , further comprising:

driving the second generator as a motor;

testing the first generator.

15 . The method according to claim 13 , further comprising:

providing information received from a set of sensors installed in both generators;

selecting a pre-established pattern of testing;

testing the generators in response to the information provided and the selected pre-established pattern.

16 . The method according to claim 15 , further comprising:

gathering test result information from the sensors in the tested generators, the test result information including at least one of instantaneous speed, power, voltage, current, airgap, vibration or temperature of the tested generator; and

storing the test result information as a footprint of the tested generator.

17 . The combination first and second generators and back-to-back testing system according to claim 10 , wherein the first opening defines a first flange and the second opening defines a second flange, the first flange being connected to a stator of the first generator and the second flange being connectable to a stator of the second generator.

18 . The combination first and second generators and back-to-back testing system according to claim 10 , wherein the hollow body is at least partially cylindrical and the test bench further comprises at least one bearing inside the hollow body for coupling the shaft to the hollow body.

19 . The combination first and second generators and back-to-back testing system according to claim 10 , wherein the test bench further comprises:

a first shaft connector coupled at a first point to the first end of the shaft, and

a second shaft connector coupled at a first point to the second end of the shaft,

wherein the first and second connectors are connectable to the first and second rotors, respectively, at a second point.