Electrical Connecting Device

Abstract

An electrical connecting device, which is immersible remote controlled and able to transmit also remote control or telemetry signals. A primary coil (15) connected to the primary circuit is arranged upon a support or rod (1) in order to be displaceable, together with the magnetic core component integral with it, relatively to the secondary coil (16) with its magnetic core portion, all this in such a fashion as to create inductive coupling for the transmission of alternating (three-phase) electrical power, and to enable said two parts to be arbitrarily interpenetrated and parted from one another, in a single operation and whatever the orientation.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a device used for transmitting electrical energy and/or electrical signals from a first circuit, referred to as the primary circuit, to a second circuit, referred to as the secondary circuit. This is an electrical connecting device in the broadest sense, designed to interconnect the two circuits in question; the invention seeks to make it possible to connect and disconnect the two circuits in an arbitrary way, and also to ensure that the electrical energy and/or electrical signals is or are transmitted satisfactorily when the device is in the connecting position.

It should be understood that although the invention is in no way limited to this application, it is especially suitable for application to circuits immersed in the sea. Submarine electrical connectors employing direct metallic contact, are subject to severe corrosion and have very poor reliability when subjected to repeated operation. In addition, and in particular in the case of associated multiple conductors, their respective plug arrangements require a positional accuracy such that it is difficult to render this operation automatic.

SUMMARY OF THE INVENTION

The object of the invention is to create a connecting device of the kind introductorily described, which is capable of being remote-controlled, without demanding stringent requirements in terms of positioning, for its fitting, and which lends itself to operation in a marine environment.

Consequently, in the case of the invention the idea was adopted of discarding direct metal contact and operating, using a.c., with an inductive connection comprising a moving part, this after it was discovered that a connection established by a mobile capacitive connector, which was an a priori possibility, involved too many difficulties.

According to the invention, there is provided a device for transmitting electrical energy or electrical signals, or both, from a primary to a secondary circuit, said device comprising a primary coil connected to the primary circuit, and a secondary coil connected to the secondary circuit, these coils being coupled inductively with one another by a magnetic circuit containing an air-gap, one of said coils being assembled upon a support for displacement, along with that part of the magnetic circuit integral with it, relatively to the other of said coils with its integral part of the magnetic circuit, such displacement being produced under the effect of means used for displacing said support, all in such a fashion as to be able to arbitrarily effect, the mutual inductive electrical connection of said primary circuit and said secondary circuit, or their disconnection, respectively by the interpenetration or parting of said two coils, this in a single operation and whatever the relative angle of positions of the coils about said axis, wherein said device operates in a polyphase fashion, for example a three-phase fashion, the primary and secondary coils being assembled in slots formed in magnetic plates arranged perpendicularly to the support axis, and being electrically connected in the manner of the rotor and stator of a polyphase asynchronous motor, and being further provided with a stop support to prevent relative rotation between fixed and moving parts.

As will be seen, in a preferred embodiment of the invention the energy transfer is effected in polyphase fashion, namely for example in three-phase fashion, the primary and secondary coils being assembled in slots in magnetic plates belonging to the coil, and being electrically connected in this way with the rotor and stator of a polyphase asynchronous motor having a wound rotor ; however, the device does not rotate and simply operates as a rotary field transformer, additional means being provided to prevent relative rotation between the two coils. Three-phase power transfer is advantageous in that it makes it possible, at that end of the secondary circuit remote from said device, to supply asynchronous motors which are more reliable than collector motors.

As far as the transfer of electrical signals is concerned, this implying that the power involved is small, this can be carried out in a different manner, as will be explained hereinafter.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be better understood and explained through the agency of the ensuing description given by way of non-limitative example, of a connecting device which effects transfer on the one hand of a certain electrical power in three-phase form, and on the other hand of electrical signals in a single-phase form, through the medium of respective, superimposed transformer elements. This description has been given with reference to the drawings in which :

FIG. 1 shows the connecting device in longitudinal section ;

FIG. 2 illustrates the same device in longitudinal section on the line II--II of FIG. 1 ;

FIG. 3 illustrates the same device in transverse section, along the line III--III of FIG. 1 ; and

FIG. 4 illustrates a variant embodiment of the device shown in FIG. 1, on a different scale.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As explained, the device in accordance with the invention and illustrated here, comprises a power transformer A and a telemetry transformer B, separate from one another but united in one and the same mechanical assembly the common displaceable part of which is supported by a rod 1, itself suspended by a cable 1a. This cable can be used not only as a supporting means but also to transmit the remote-control and telementry signals, as well as the electrical power (the connections to the coils have not been shown in the Figure).

As far as the power transformer A is concerned, this is a three-phase type employing a quasi-cylindrical transformer the two parts, moving (primary) and fixed (secondary) of which are designed exactly like the rotor and stator of a three-phase asynchronous motor with coil windings.

The magnetic circuit is constituted by a stack of insulated plates 2 having a thickness preferably in the order of 0.3 mm. The primary and secondary windings are wound in slots 3 formed along generatrices of the cylinder. The conductors corresponding to each phase occupy one slot in three. The total number of slots is 12 in the present instance.

In practice, in order to facilitate the fitting of the moving part (primary) in the fixed part (secondary), the shape of the air gap is not cylindrical but is given a slight taper towards the base.

The primary windings 15 are supplied directly from the three-phase 44OV (between phases) mains, at a frequency of 50 or 60 c/s, for example.

The primary windings create in the air gap, a rotating radial magnetic field substantially at right angles to the longitudinal axis X--X, which field induces in the secondary windings 16, wound in the same fashion as the primary windings, electromotive forces which reconstitute a balanced three-phase system, similar to that of the mains.

It should be pointed out that this kind of transformer could equally well be used to modify the form in which the electrical energy is available. Thus, in order to obtain a balanced three-phase system, the secondary coil must be similar to the primary (same number of slots) but it is not necessary however for the ratio between the number of turns of the windings to be equal to 1 ; the transformation ratio can be chosen so that the secondary voltage has the value most suited to the particular application (for example, a secondary voltage of 24V can be obtained from a primary for 44OV). It is also possible to create a secondary circuit comprising a number of slots double that of the primary and a winding such that a six-phase secondary voltage is obtained : this may be useful if the said secondary voltage is to be subsequently rectified in order to for example charge batteries, since the residual ripple is less in a six-phase system than it is in a three-phase system.

The magnetic plates, in order to avoid direct contact between them and the seawater, are covered in both parts of the transformer, with a protective coating 4. The magnetic circuit is thus cut by an air gap of several millimeter in addition to any residual seawater which is left. It should be pointed out that the power transfer takes place with an efficiency of less than unity. If a continuous power of 0.5 kw is required at the secondary, with powers of up to 2kw during short periods of time, then the transformer must be overdimensioned to cope with this, so that the permissible power at the primary is sufficient for it to compensate for the losses in all cases.

It should also be pointed out, however, that the efficiency increases with power because at the same time the dimensions of the magnetic circuit increase whilst the air gap remains substantially constant.

In the embodiment illustrated, it was required to transmit at the same time as the power, remote-controlled and telemetry signals, these through circuits separate from those carrying the heavy-current power and having much higher frequencies (some few kc/s instead of 50-60 c/s). The two respective connecting devices are here combined in one, one and the same support 1 supporting the displacement parts of the two devices or individual transformers, but precautions advantageously being taken to prevent parasitic signals stemming from the power circuits, from mixing with the inner control and telemetry signals. For this purpose, the planes of the turns constituting the respective coils of the two transformers, are practically at right angles to one another. Whereas the primary and secondary coils of the power transformer are designed in the manner of the rotor and stator of a three-phase asynchronous motor, producing a rotating radial field perpendicular to the longitudinal axis of the device, the other set of coils, belonging to the transformer for the remote control and telemetry signals, being perpendicular to the axis operates in single-phase fashion and produces a fixed field. In the case of this latter set, the signals having frequencies within the band from one to 10 kc, the core of the transformer can be made up of a certain number of standard C-circuits 11, 12, distinct from one another and directed radially and juxtaposed, the circuits being made of high-permeability (.mu.- metal) magnetic plates having a thickness of around 0.05 mm, or of ferrite ; around these magnetic components, the corresponding torroidal coils 13 and 14, of axis X--X, are arranged.

It is also possible to add, in the remote control and telemetry circuit, a high-pass filter which eliminates signals of frequency lower than 1,000 c/s, this filter (not shown) being incorporable in the connecting device in accordance with the invention.

It should be borne in mind that the impedance of the primary winding of the telementry transformer varies rapidly as a function of the position of the primary in relation to the secondary (penetration of the moving component). This may provide a convenient means, using a meter to measure the impedance, of effecting a remote check upon whether or not the displaceable component is correctly inserted.

The disposition of the two components of the connecting device, as illustrated in the FIG. 1, could be reversed (male component fixed and female component mobile). However, this kind of arrangement does not appear to be so desirable, because the moving part would be bulkier and have a higher inertia, probably making operation more difficult. Likewise, the telemetry transformer could be arranged below the power transformer.

The magnetic circuits and the windings are epoxy resin impregnated. Moreover, the two parts of the device have a neoprene coating 4,2 mm thick approximately, which provides protection against corrosion and also produces a certain degree of damping of vibrations.

In the case where the alignment area is small (< .+-. 15 mm), the tapered shape of the air gap is adequate to provide guidance of the moving component, at the time of insertion. In the case where alignment areas of up to as much as 150 mm can arise, it is necessary to equip the female part with a guide cone 7 the aperture of which has a diameter of around 560 mm (FIG. 4). In this figure, in broken line, the position of the moving component when it is not exactly upon the axis, can be seen. To provide a concrete idea of what is involved, it is worthy of mention that in a practical embodiment, the mass of the moving component is around 100 kgs and that of the fixed component around 400 kgs.

It will be seen, too, that the axis of the moving component is hollow and this could possibly be exploited to effect guidance by cable, from the surface.

Also, from a consideration of FIG. 4, it will be observed that a diaphragm 8 may be provided as anti-fouling means, and a cavity 9 to receive biological deposits and act as a reservoir for anti-fouling agents, with a bellows outlet 10 to enable the water displaced by the introduction of the mobile part as it descends into the fixed part, to take place. The power transformer being wound like an asynchronous motor, there is a couple which is a function of the load impedance, which tends to turn the moving component in relation to the fixed. A simple anchoring system 5, for example using dogs, is provided to prevent any risk of rotation.

The fixed and moving parts will be equipped in each case with a section of cable (primary 1a or secondary 6) with five conductors (3 for the power and 2 for the telemetry and remote control data), whose length, chosen as a function of the installation conditions, may reach some few meters. The extremity of the cable will be equipped with a connector so that at the surface, it can be connected to the rest of the system ; in order to provide a seal, this connector will be provided with a moulded envelope, prior to immersion.

The technique of the manufacture of magnetic circuits in the form of insulator plates, is well-known in the context of motor bodies. This method of construction provides great mechanical strength, something which could not be obtained by using ferrite materials.

The surfaces which are in contact with the water are coated with marine type neoprene to which an anti-fouling product has been added, thus providing protection against corrosion and marine organisms. Various means are available to provide supplementary protection for the walls of the airgap (fixed part), against biological deposits during periods of disconnection (sealing by using a diaphragm, filling with a non-miscible liquid having a density greater than that of sea water, reservoir of anti-fouling agent).

The device is completely static and has no active electronic component. On the other hand, the power transformer will be overdimensioned so that the losses do not give rise to excessive heating, even locally (a rise in temperature in the order of 10.degree. after some few minutes of operation at maximum power, is permissible). Under these conditions, the service life of the connector will not be limited by electrical failures.

Of course, the invention is not limited to the embodiment hereinbefore described and shown which was given merely by way of non-limiting example.

Claims

What is claimed is :

1. In an electrical connecting device for transmitting electrical energy from a first part to a second part, said parts being displaceable relatively to one another, comprising, a primary coil connected to said first part, a secondary coil connected to said second part, said coils having same axis of symmetry, a magnetic circuit with an air gap, and said magnetic circuit consisting of magnetic plates, means for displacing one of said parts relatively to said another part whereby to inductively couple said coils which are integral with said parts respectively when said coils have been properly displaced, and said inductive coupling being achieved irrespective of the relative angle of said coils about said axis of symmetry, the improvement of having slots formed in said magnetic circuit for housing said primary and secondary coils respectively, said coils being electrically connected as the rotor and the stator of a polyphase asynchronos motor, and stop support for preventing relative rotation between said displaceable parts of said connecting device.

2. In an electrical connecting device according to claim 1, for transmitting electrical energy together with electrical signals from a first part to a second part, the provision of a second set of coils independant from the first set comprising a primary coil connected to said first part and a secondary coil connected to said second part, a magnetic circuit with an air gap, said coils of the second set being inductively coupled through said air gap, as said first and second parts are properly displaced to inductively couple said first set of coils, and both said sets of coils having their respective planes of turns substantially at right angle to one another.

3. An electrical connecting device according to claim 2, wherein said first set of coils for transmitting electrical energy produces a radial rotating field perpendicular to said axis of symmetry of said coils, whereas said second set of coils for transmitting electrical signals produces a fixed field and operates in a single-phase manner.

4. An electrical connecting device according to claim 2, wherein said means for displacing one of said parts relatively to the other is lifting means for enabling one of said parts as a mobile part to slide into said another part as a fixed part along said axis of symmetry, whereby to establish the inductive coupling of both said sets of coils respectively when said moving part is set in said fixed part, and to disconnect said coupling when said moving part is lifted outside said fixed part.

5. An electrical connecting device according to claim 4 wherein said moving part which penetrates into said fixed part is given a tapered outline and said fixed part is given a corresponding outline to fit said tapered outline.

6. An electrical connecting device according to claim 5, wherein further said fixed part is provided with external guide means for facilitating the sliding in of said moving part into said fixed part.

7. In an electrical connecting device according to claim 2, designed to operate in a corosive medium wherein said magnetic circuits comprise an air gap and said air gap may possibly contain said corrosive medium, the provision of a protective coating for protecting the plates of said magnetic circuits against corrosion by said corrosive medium.

8. An electrical connecting device for transmitting electrical energy and electrical signals, said device operating in a corrosive medium such as seawater, comprising a first part and a second part which are displaceable relative to each other along a common axis of symmetry, a first and a second primary coils connected to said first part and said coils being independant from each other, a first and a second secondary coils connected to said second part and said coils being independant from each other, a first magnetic circuit with an air gap and a second magnetic circuit with an air gap, said magnetic circuits being respectively associated with said first and second primary and secondary coils respectively, means for displacing said first and second parts with their integral coils and magnetic circuits, relatively to one another, and said first primary and secondary coils, as a first set of coils, so as said second primary and secondary coils as a second set of coils, being inductively coupled through said air gaps respectively of said magnetic circuits, when said one part is displaced along said axis of symmetry into said other part, the coils of one set being arranged so as to produce a radial rotating field perpendicular to said axis whereby, to transmit said electrical energy, the coils of the other set being arranged so as to produce a fixed field whereby to transmit said electrical signals, stop support for preventing relative rotation between said displaceable parts and protective coating in said air gaps for protecting said magnetic circuits against corrosion by seawater.