Apparatus for transferring electrical energy

1. An azimuth thruster for propelling a marine vessel, the thruster comprising:

an upper housing;

a lower housing, the lower housing being arranged to rotate relative to the upper housing;

a first body arranged within the upper housing, the first body comprising a plurality of capacitively loaded first inductors forming a tuned LC circuit to provide a magnetic field; and

a second body arranged within the lower housing, the second body comprising a plurality of capacitively loaded second inductors forming a tuned LC circuit to generate an electrical current from the magnetic field to transmit power between the first and second bodies,

wherein each of the first and second bodies comprises a ring, and the plurality of capacitively loaded first inductors and the plurality of capacitively loaded second inductors are concentrically configured at multiple different radial positions within the respective first and second bodies, each capacitively loaded second inductor being located in a matching circumferential and radial location relative to a respective capacitively loaded first inductor, first and second bodies being configured to provide a constant degree of overlap at all relative rotational positions such that, in use, the power transmission between the first and second bodies is continuous and constant at all relative rotational positions, and

wherein each of the plurality of capacitively loaded first inductors is tuned to resonate within a predetermined frequency band and each of the plurality of capacitively loaded second inductors is tuned to resonate within a predetermined frequency band, the frequency band of each of the plurality of second inductors at least partially overlapping with the frequency band of each of the plurality of first inductors.

2. The azimuth thruster as claimed in claim 1 , the first body being fixedly attached to and spaced from the upper housing via one or more first attachment members.

3. The azimuth thruster as claimed in claim 2 , the one or more first attachment members forming, in use, a support structure for maintaining a position of the first body relative to the upper housing.

4. The azimuth thruster as claimed in claim 1 , the second body being fixedly attached to and spaced from the lower housing via one or more second attachment members.

5. The azimuth thruster as claimed in claim 4 , the one or more second attachment members forming, in use, a support structure for maintaining a position of the second body relative to the lower housing.

6. The azimuth thruster as claimed in claim 5 , the support structure comprising a frame which is fixedly attached, in use, to the lower housing.

7. The azimuth thruster as claimed in claim 1 , the first body comprising a plurality of first inductors to provide the magnetic field.

8. The azimuth thruster as claimed in claim 1 , the second body comprising a plurality of second inductors to generate the electrical current from the magnetic field.

9. The azimuth thruster as claimed in claim 1 , one or more of the plurality of at least one first inductors and the plurality of at least one second inductors being configured on separate parts of the first body and second body respectively.

10. The azimuth thruster as claimed in claim 1 , any one or more of the plurality of at least one first inductors and/or the plurality of at least one second inductors being equidistantly spaced around the perimeter of the respective bodies.

11. The azimuth thruster as claimed in claim 1 , any one or more of the plurality of at least one first inductors and/or the plurality of at least one second inductors being disproportionately spaced around the perimeter of the respective bodies.

12. The azimuth thruster as claimed in claim 1 , the first and second bodies being spaced between 1 mm to 100 mm apart.

13. The azimuth thruster as claimed in claim 1 , the first and second bodies being spaced between 10 mm to 20 mm apart.

14. The azimuth thruster as claimed in claim 1 , each body comprising a conductive material.

15. The azimuth thruster as claimed in claim 1 , each body comprising a facing surface comprising one or more of a flat or textured surface.

16. The azimuth thruster as claimed in claim 1 , one of first and second bodies being concentrically arranged relative to the other of the first and second bodies.

17. The azimuth thruster as claimed in claim 1 , further comprising radio frequency communication circuitry coupled to the at least one second inductor to receive electrical energy from the at least one second inductor.

18. The azimuth thruster as claimed in claim 17 , further comprising a sensor to sense an operating condition of at least a part of the thruster, the radio frequency communication circuitry being coupled to the sensor and being configured to transmit a wireless signal for the sensed operating condition.

19. The azimuth thruster as claimed in claim 1 , further comprising a controller to control the lower housing to rotate relative to the upper housing.

20. A vessel comprising the azimuth thruster as claimed in claim 1 .

21. An azimuth thruster for propelling a marine vessel, the thruster comprising:

an upper housing;

a lower housing, the lower housing being arranged to rotate relative to the upper housing;

a first body arranged within the upper housing, the first body comprising a plurality of capacitively loaded first inductors forming a tuned LC circuit to provide a magnetic field, wherein each of the first inductors is configured as a discrete module; and

a second body arranged within the lower housing, the second body comprising a plurality of capacitively loaded second inductors forming a tuned LC circuit to generate an electrical current from the magnetic field, wherein each of the second inductors is configured as a discrete module,

wherein each of the first and second bodies comprises a ring, and the plurality of capacitively loaded first inductors and the plurality of capacitively loaded second inductors are concentrically configured at multiple different radial positions within the respective first and second bodies, each capacitively loaded second inductor being located in a matching circumferential and radial location relative to a respective capacitively loaded first inductor, the first and second bodies being configured to provide a constant degree of overlap at all relative rotational positions such that, in use, the power transmission between the first and second bodies is continuous and constant at all relative rotational positions, and

wherein each of the capacitively loaded first inductors are tuned to resonate within a predetermined frequency band and each of the second inductors are tuned to resonate within a predetermined frequency band, the frequency band of each of the capacitively loaded second inductors at least partially overlapping with the frequency band of each of the first inductors.

22. The azimuth thruster as claimed in claim 21 , wherein the plurality of capacitively loaded first inductors are circumferentially positioned with the first body at one or more respective radial locations, and wherein the plurality of capacitively loaded second inductors are circumferentially positioned with the second body at matching circumferential and/or radial positions relative to the plurality of first inductors.

23. A vessel comprising the azimuth thruster as claimed in claim 21 .