ELECTRICAL MACHINE AND MAINTENANCE METHODS THEREOF
FIG9 schematically represents a frontal view of an example of an electrical machine in a second position
In FIG9, the rotor is positioned in the second position. The rotor may be rotated from the first to the second position without reconnecting the removed segment corresponding to the maintenance aperture 31 to the other parts of the electrical conductor ring for example for repairing or performing maintenance or inspecting operations in the first region 21 of the inner structure. The second region 22 of the inner structure 20 may be accessible through the maintenance aperture when the rotor is in the second position. However, the first region 21 cannot be accessible through the maintenance aperture.
frontal view
8
through two rotor bearings single rotor bearing
30
structure
9
frame
2
tower
20
structure
21
first region
31
maintenance aperture maintenance apertures
['1. An electrical machine (10) having a plurality of electrical phases and comprising an inner structure (20), an outer structure (30) and an air gap (40) arranged between the inner (20) and the outer structure (30); wherein the inner structure (20) is one of the rotor and of the stator and the outer structure (30) is the other of the rotor and of the stator; the rotor is configured to rotate around a rotational axis (50) extending from a first side (51) to a second side (52), and the stator comprises a plurality of electrical windings (53) and an electrical conductor ring (54) extending along the stator circumference for connecting the electrical windings (53) to an electrical converter; the outer structure (30) comprises at least one maintenance aperture (31) extending along a portion of the outer structure (30) for accessing a portion of the inner structure (20) from the first side (51); and the electrical conductor ring (54) comprises a plurality of segments (60) having a releasable segment (61) being releasable connected to the other segment or segments of the electrical conductor ring (54), wherein the releasable segment (61) is configured to connect to a selection of the electrical windings (53), the selection having the same number of windings (53) for each of the plurality of electrical phases.', '8. A method of performing maintenance operations (100) in an electrical machine (10), the electrical machine (10) having a plurality of electrical phases and comprising an inner structure (20), an outer structure (30) and an air gap (40) arranged between the inner (20) and the outer structure (30), the inner structure (20) being one of the rotor and of the stator and the outer structure (30) being the other of the rotor and of the stator; the method comprising: positioning (101) the rotor in a first position for accessing a first region (21) of the inner structure (20) through a maintenance aperture (30) in the outer structure (30); disconnecting (102) a portion of the plurality of electrical windings (53) of the stator from an electrical conductor ring (54) extending along the stator circumference for connecting the electrical windings to an electrical converter; removing (103) one or more segments of the electrical conductor ring (54) at least partially corresponding to the maintenance aperture (31) in the first position; positioning (105) the rotor in a second position for accessing a second region (22) of the inner structure (20) through the maintenance aperture (31), without connecting the removed segments of the electrical conductor ring to the remaining segment or segments of the electrical conductor ring (54).']