(19)
(11) EP 0 908 983 A2

(12) EUROPEAN PATENT APPLICATION

(43) Date of publication:
14.04.1999 Bulletin 1999/15

(21) Application number: 98203398.7

(22) Date of filing: 09.10.1998
(51) International Patent Classification (IPC)6H01R 39/64
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 10.10.1997 IT MI972308

(71) Applicant: ABB Sistemi Industriali SpA
20099 Sesto San Giovanni (MI) (IT)

(72) Inventor:
  • Sozzi, Luigi
    27051 Cava Manara (PV) (IT)

(74) Representative: Giavarini, Francesco 
ABB Ricerca S.p.A. Viale Edison, 50
20099 Sesto San Giovanni (MI)
20099 Sesto San Giovanni (MI) (IT)

   


(54) Electrical power transmission system to a propulsion and steering module for naval ships


(57) Electrical power transmission system between one or more pairs of con ductors (6,14), the particularity of which consists in comprising:
  • a first sliding contact means (7), connected to a first conductor of one or more pairs of conductors; and
  • a second sliding contact means (25), connected to a second conductor of said one or more pairs of conductors; and
  • a third sliding contact means (8) in continuous relative motion in relation to said first and second sliding contact means.





Description


[0001] The present invention relates to an electrical power transmission system between one ore more pairs of conductors, particularly for electricity transmission to a propulsion and steering module for naval ships of the POD type.

[0002] In commonly used propulsion and steering modules for naval ships, the electrical power transmission between a power supply housed in the ship hull and a motor housed inside the pod of the propulsion and steering module, is performed by means of a series of brushes integral to the ship frame, and therefore always fixed, and a series of conductive rings mounted on the propulsion and steering module stem, solidly rotating with it.

[0003] Alternatively, electrical power transmission can also be performed by means of brushes solidly rotating with the propulsion and steering module stem, and conductive rings integral to the ship frame, and therefore fixed.

[0004] In both cases, since ships generally navigate at cruising speed for long periods, the propulsion and steering module stays fixed in relation to the ship hull, and consequently the position of brushes is fixed in relation to the conductive rings. In this way, current flows always through the same points from the power supply to the electric motor. This causes serious problems because the brush-ring surfaces do not perfectly match and so electrical current can not uniformly distribute but passes through preferred contact points.

[0005] This causes local temperature increase, consequently causing micro-craters. The contact resistance grows causing a self-feeding phenomenon. Besides, on the ring parts normally not in contact with the brushes, can occur superficial coats due to oxidation phenomena facilitated by the marine environment.

[0006] During operating manoeuvre, the brushes come in contact with these surfaces. This causes bad conduction and local temperature increase, due to the high contact resistance; besides, brushes deterioration occurs because of their own foul.

[0007] The main task of the present invention is therefore to realize an electrical power transmission system between one or more pairs of conductors, which allows to obtain an optimal conduction, avoiding wear between brushes and contacts.

[0008] As part of this task, one object of the present invention is to provide an electrical power transmission system between one or more pairs of conductors which allows to avoid the forming of a coat due to oxidation phenomena facilitated by the marine environment.

[0009] Another object of the present invention is to provide an electrical power transmission system between one or more pairs of conductors, which can be used in propulsion and steering module naval ships.

[0010] This task, together with these and other objects that shall emerge more clearly hereinafter are achieved by an electrical power transmission system between one or more pairs of conductors characterised by the fact that it comprises a first sliding contact means connected to a first conductor of said one or more pairs of conductors, a second sliding contact means, connected to a second conductor of said one or more pairs of conductors, and a third sliding contact means in continuous relative motion in relation to said first and second sliding contact means.

[0011] In this way the electric contact between the sliding contact means occurs along mobile contact surfaces, thus avoiding the cited problems in that all the surface is involved in current flow. A further advantage is due to the fact that the continuous relative motion between the sliding means prevent the occurring of the surface coat.

[0012] Further advantages and characteristics of the present invention, will emerge from the description of a number of preferred but not exclusive embodiments of the electrical power transmission system according to the invention, illustrated purely by way of example and without limitation with the aid of the attached drawings in which:

figure 1 shows a naval ship with a propulsion and steering module;

figure 2 shows a longitudinal section of the electrical power transmission system according to the invention;

figure 3 shows a cross section taken along the plan III-III of figure 2.



[0013] In particular figure 1 shows a naval ship 1 on the hull of which a propulsion and steering module 2 of the POD type is mounted, comprising a pod 40 and a support 50, electrically fed by means of the electrical power transmission system 3.

[0014] Figure 2 and 3 show a preferred embodiment of the electrical power transmission system. In this embodiment, a pair of conductive cables 6 and 14 are connected to, respectively, a first sliding contact means 7 and a second sliding contact means 25 of the electrical power transmission system according to the invention.

[0015] In the illustrated embodiment the first sliding contact means 7 are made of brushes coupled to the ship frame 1 and therefore fixed; the second sliding contact means 25 is made of graphite rings 12 and of conductive rings 11 coupled each other and to the stem 5 of the propulsion and steering naval ship 2.

[0016] The second sliding contact means are electrically insulated from the stem 5 by insulating means 13. Between the brushes 7 and the graphite rings 12, a third sliding contact means 8 are provided, fixed on the support means 10 and electrically insulated by insulating means 9.

[0017] In the embodiment illustrated, the sliding contact means 8 are made of rotating conductive rings and the support means 10 are made of a rotating roll holding rings.

[0018] Alternatively, the first sliding contact means 7 can be made of graphite rings, and the graphite rings 12 can be made of brushes. The rotating roll 10 can be realised with metallic material or plastic-composite material thus making the insulating means 9 useless.

[0019] Alternatively, the supporting means 10 can be made of a set of rotating stems holding the rings or the brushes.

[0020] Driving and guiding means 17 directly operate on said rotating roll 10, comprising in the illustrated embodiment, a motor 16 driving a gear 18-pinion 15 system and a sliding guide 20. The guide 20 can be made of a circular rail, or anyway of sliding means facilitating the rotation of the roll 10.

[0021] The electric motor 16 acts on the gear 18-pinion 15 system which operates on the rotating roll 10, making it rotate inside the guide 20. In this way, being the rotating rings 8 constrained to said roll 10, they also rotate generating a continuous sliding contact, both with the brushes 7 and the graphite rings 12, along all the surface of the rotating ring 8 itself, even when the ship navigates at cruise speed, and the propulsion and steering module is fixed in relation to the ship hull.

[0022] A particular application of the electrical power transmission system according to the invention, occurs when a propulsion and steering module for naval ships comprising a submerged watertight pod, inside which an electric motor is housed, and a substantially vertical support, the bottom part of which is joined to the pod and the top part of which is connected to the hull of said naval ship in such a way as to be able to rotate in relation to the longitudinal axis of the hull and inside which electronic power and control modules are housed.

[0023] In this case the power supply between the fixed part (hull) and the mobile part (pod and support) conveniently occurs by means of two direct current conductors only, and, as a consequence, the electrical power transmission system according to the invention comprises two rotating conductive rings only. With this solution contacts wear is not uniformly distributed for both the polarities, but this phenomenon can be easily compensated employing known techniques.

[0024] When the power and control electronic modules are housed inside the ship hull, the power supply between the fixed part (hull) and the mobile part (pod and support) occurs by means of alternate current, and the number of conductors ranges accordingly from 3 to 8, in case of synchronous motor, asynchronous motor, three-phase motor, or hexa phase motor; as a consequence, the electrical power transmission system also comprises a number of rotating conductive rings ranging from 3 to 8.

[0025] The electrical power transmission system as conceived is capable of numerous modifications and variants that are all within the inventive concept; moreover all the details may be substituted by other technically equivalent elements. In practice the dimensions and materials used can be of any kind to suit the requirements of the state of technology, providing they are compatible with the specific use.


Claims

1. Electrical power transmission system between one ore more pairs of conductors characterised by the fact that it comprises:

- a first sliding contact means, connected to a first conductor of one or more pairs of conductors;

- a second sliding contact means, connected to a second conductor of said one or more pairs of conductors;

- a third sliding contact means in continuous relative motion in relation to said first and second sliding contact means.


 
2. Electrical power transmission system according to claim 1, characterised by the fact that said third sliding contact means comprise:

- a rotating conductive ring for each pair of conductors;

- electric insulating means for said rotating conductive rings;

- supporting means of said rotating conductive rings;

- operating and guiding means of said supporting means.


 
3. Electrical power transmission system according to one or more of the previous claims, characterised by the fact that said supporting means are constituded of a rotating roll.
 
4. Electrical power transmission system according to one or more of the previous claims, characterised by the fact that said supporting means are constituted of a series of rotating stems.
 
5. Electrical power transmission system according to one or more of the previous claims, characterised by the fact that said operating and guiding means comprise a gear-pinion system.
 
6. Electrical power transmission system according to one or more of the previous claims, characterised by the fact that said operating and guiding means comprise a circular rail for the guide of said supporting means.
 
7. Electrical power transmission system according to one or more of the previous claims, characterised by the fact that it comprises:

- brushes connected to the conductors, said conductors being connected to an electrical power source;

- graphite rings and conductive rings coupled each other and fixed to a rings-holder stem, said conductive rings being connected to the supply cables of a consumer electric device and electrically insulated from said stem by insulating means;

- rotating conductive rings interposed between said brushes and said graphite rings, said rotating conductive rings being in continuous relative motion in relation to said brushes and to said graphite rings, realising a continuous sliding contact with both them;

- electrical insulating means for said rotating conductive rings;

- a rotating roll for supporting said rotating conductive rings; and

- an electric motor, a gear-pinion system, and a slipping circular rail, for the handling and guiding of said rotating roll.


 
8. Propulsion and steering module for naval ship comprising a submerged watertight pod containing an electric motor, and a cooling circuit comprising a pump and a heat exchanger;

- a substantially vertical support, the bottom part of which is fixed to said pod and the top part of which is connected to the hull of said naval ship in such a way as to be able to rotate in relation to the longitudinal axis of the hull;
characterised by the fact that it comprises an electrical power transmission system according to one or more of the previous claims.


 
9. Propulsion and steering module for naval ship according to claim 8, characterised by the fact that the power and control electronic modules of the electric motor are housed inside the support and the supply of said electric motor occurs by means of two direct current conductors.
 
10. Propulsion and steering module naval ship according to claim 8, characterised by the fact that the power and control electronic modules of the electric motor are housed inside the hull of a naval ship, and the power of said motor occurs by means of at least three alternate current conductors.
 
11. Propulsion and steering module naval ship comprising:

- a submerged watertight pod, containing a cooling circuit comprising a pump and a heat exchanger; and a permanent magnet multielectronic rotating motor or a variable reluctance motor;

- a substantially vertical support, the bottom part of which is fixed to said pod and the top part of which is connected to the hull of said naval ship in such a way as to be able to rotate in relation to the longitudinal axis of the hull, said support comprising power electronic modules and access means to said support characterised by the fact that it comprises an electrical power transmission system, from a supply system housed in the hull to said multielectronic motor housed in the pod, according to claims from 1 to 7.


 




Drawing