GB2433354A

GB2433354A - Electrical contact arrangement

Info

Publication number: GB2433354A
Application number: GB0525512A
Authority: GB
Inventors: Joseph Paul Fakult; Raymond Richard Bomford
Original assignee: Goodrich Control Systems
Current assignee: Goodrich Control Systems
Priority date: 2005-12-14
Filing date: 2005-12-14
Publication date: 2007-06-20
Also published as: GB0525512D0

Abstract

An electrical module comprises a substrate 18 upon which an electrical component 26 such as a diode, is mounted, a terminal 24, and a contact arrangement 32 providing an electrical connection between the terminal 24 and the electrical component 26. The contact arrangement comprising a contact element having a terminal region 34 connectable to the terminal 24, first and second contact regions 40, 42 which lie substantially in the same plane as one another, and first and second intermediate regions 44, 46 interconnecting the first and second contact regions 40, 42, respectively, and the terminal region 34. The first and second intermediate regions 44, 46 upstanding from the plane of the first and second contact regions 40, 42 and being arranged, in use, to transmit a compressive load to the contact regions 40, 42 to urge them toward the electrical component 26. The contact arrangement is used in the module, and at least one module is serving to form a rectifier arrangement for the output of an electrical generator.

Description

I

Electrical Contact Arrangement This invention relates to an electrical contact arrangement, and in particular to an arrangement suitable for use in an electrical module, for example a diode assembly. The diode assembly may be used in the rectification of the output of an electrical generator, for example for use in aerospace applications.

In aerospace applications and many other applications, where a DC electrical current is required, it is known to use an electrical generator having an AC output, and to use a rectifier arrangement to produce a DC output from the AC output of the generator.

Conventional rectifier arrangements use individual stud diodes mounted directly to heat sinks secured within the generator. Although such arrangements usually operate satisfactorily, they have the disadvantages that the arrangements take up a relatively large amount of space, and also that the individual mounting and wiring of each stud diode results in assembly process being relatively complex and time-consuming.

The use of modules containing a plurality of diodes configured so as to allow the diodes to be used in a rectifier arrangement has been considered so as to save space and simplify assembly. However, there is some concern over the ability of certain designs of modules of this type being able to maintain the required electrical contact between components thereof after having been exposed to vibrations and repeated extreme changes in operating temperature as occur in aerospace applications. It is an object of the invention to provide an electrical contact arrangement, and a module for example a diode module incorporating such an arrangement, in which the disadvantages set out hereinbefore are reduced.

According to the invention there is provided an electrical contact arrangement comprising a contact element having a terminal region, first and second contact regions, the first and second contact regions being, in use, substantially co-planar, and first and second intermediate regions interconnecting the first and second contact regions, respectively, and the terminal region, the first and second intermediate regions each being upstanding from the plane of the first and second contact regions.

The first and second contact regions conveniently extend parallel to one another and conveniently lie on opposite sides of a plane containing the first and second intermediate regions.

This arrangement is advantageous in that, in use, a connector connected to the terminal region can apply a compressive load to the contact regions through the upstanding intermediate regions, the load assisting in maintaining electrical contact between the contact regions and a component electrically connected thereto. Further, the load is applied independently to the contact regions.

The invention also relates to an electrical module comprising a substrate upon which an electrical component is mounted, a terminal, and a contact arrangement providing an electrical connection between the terminal and the electrical component, the contact arrangement comprising a contact element having a terminal region connectable to the terminal, first and second contact regions which lie substantially in the same plane as one another, and first and second intermediate regions interconnecting the first and second contact regions, respectively, and the terminal region, the first and second intermediate regions upstanding from the plane of the first and second contact regions and being arranged, in use, to transmit a compressive load to the contact regions to urge them toward the electrical component.

As the intermediate regions are upstanding, the direction in which the compressive load is applied is substantially perpendicular to the plane containing the contact regions, so the application of shearing forces is reduced or avoided.

Conveniently, the electrical component comprises a diode. Preferably, the module incorporates several such electrical components and associated connector arrangements.

The connector arrangement conveniently comprises a resilient copper material, preferably beryllium copper.

The connector regions may be soldered to the electrical component, for example using a gold/tin or lead/tin solder. However, arrangements which are not soldered are also envisaged.

The connector arrangement is preferably integrally formed, but could alternatively be of multi-part construction. For example the first intermediate region and first contact region could be formed as a separate component to the second intermediate region and second contact region, the terminal region being defined by parts of both elements.

The connector arrangement may include a third contact region and associated third intermediate region.

The invention further relates to an electrical generator comprising a rotor rotatable relative to a stator, and at least one module as described hereinbefore serving to form a rectifier arrangement for the output of the generator.

The invention will further be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a view of an electrical generator; Figures 2 and 3 are views illustrating one of the modules used in the generator of Figure 1; and Figure 4 is a diagram illustrating the contact arrangement part of the modules.

Figure 1 illustrates a generator intended for use in aerospace applications. The generator comprises a rotor rotatable relative to a stator to produce an AC output. The output of the generator is passed through a full wave bridge rectifier arrangement 10 to produce a DC output. The bridge rectifier arrangement is made up of a series of diode modules 12 mounted to heat sinks 14 within the generator by bolts 16 or other suitable connectors.

Figures 2 and 3 illustrate the diode modules 12 in greater detail. As illustrated, each module 12 comprises a substrate 18 in which are formed apertures 20 through which the bolts 16 pass to secure the diode modules 12 in position. The substrate 18 is of a copper material. The substrate 18 is shaped to define a recess 22 within which terminal blocks 24 are provided to enable connection of the generators electrical windings to the diode modules 12. Adjacent each terminal block 24 is located an associated diode component 26. Each component 26 comprises a semi-conductor die layer 28 sandwiched between layers 30 of gold-plated molybdenum or tungsten. All layers of the component 26 are soldered using a lead/tin solder.

Interconnecting each terminal block 24 and the associated component 26 is a connector arrangement in the form of a connector element 32. The connector element 32 is shown in greater detail in Figure 4 and comprises a strip of a resilient copper material, preferably beryllium copper which is shaped to define a terminal region 34 in which is formed an opening 36 to allow a bolt 38 or other screw-threaded connector to be used to secure the terminal region 34 to the terminal block 24. The connector element ftirther comprises a first contact region 40 and a second contact region 42 connected via respective first and second intermediate regions 44,46 to the terminal region 34. A third intermediate region 48 further connects the terminal region 34 to a third contact region 50 (not visible in Figure 4).

As best shown in Figure 3, the first, second and third contact regions, 40,42,50 are substantially co-planar, the first contact region 40 and second contact region 42 lying on opposite sides of a plane containing the first, second and third intermediate regions 44,46, 48. The intermediate regions 44, 46, 48 extend substantially vertically in the orientation illustrated in Figure 3. The lengths of the vertically extending parts of the intermediate regions 44, 46, 48 are such that, in the assembled module, the top ends of the vertical parts of the intermediate regions 44, 46, 48 are located at a height or distance greater than that of the associated terminal block 24, with respect to the substrate 18, with the result that a load applied by the securing of the connector 38 to the terminal block 24 results in resilient flexing of part of the element 32, and hence in the transmission of a compressive load through the intermediate regions 44, 46, 48 in a substantially vertical direction, in the orientation illustrated in Figure 3 urging the first, second and third contact regions 40, 42, firmly into engagement with the component 26. The direction in which the compressive load is applied is such that no or minimal shearing forces are applied between the contact regions, 40, 42, 50 and the component 26.

The magnitude of the vertical compressive load applied to the contact regions 40, 42, 50 is preferably in the range of 5-10 pounds. In some circumstances, this loading alone may be sufficient that electrical contact is maintained between the connecting element 32 and the component 26. However, it is envisaged that, in addition to the application of this compressive loading, the contact regions 40, 42, 50 will be soldered to the component 26, for example using a gold/tin solder. This choice of solder is advantageous in that it is less brittle than other conventional forms ofsolder. It will be appreciated that such a solder joint is subject to reduced stresses due to the avoidance of the application of shearing forces.

The third intermediate region 48 is formed with an opening 52 to which is soldered a connector 54 of a sense diode 56. The sense diode 56 is connected to a bus bar 58 which in turn is connected to an output terminal 60.

A silicone material potting compound 62 is provided in the recess 22 as ifiustrated in Figure 3.

The first, second and third intermediate regions 44,46,48 are separated from one another by means of slots 64. In the arrangement illustrated in Figure 4, the slots 64 extend over the full height of the vertical part of the connecting element 32, in the orientation illustrated in Figure 3, and extend over part of the horizontal region thereof. This need not always be the case. However, it is envisaged that it is desirable for the slots 64 to terminate between approximately the positions of the dashed lines 66 in Figure 4.

As described hereinbefore, the arrangement of the invention is advantageous in that a compressive load can be applied between the contact regions and the electrical component 26, this loading being applied without any significant side loading. The loading being applied about substantially the centreline of the component 26. Although the arrangement illustrated hereinbefore includes three contact regions, it will be appreciated that arrangements with more or fewer contact regions are possible. However, it is desirable for the arrangement to be symmetrical in order to avoid twisting type loads. The arrangement is advantageous in that each contact region is separately connected to the component. As a consequence, if the connection between one of the contact regions and the component fails, this should not result in total failure of the electrical connection to the component.

It will be appreciated that a range of other modifications and alterations may be made to the arrangement described hereinbefore without departing from the scope of the invention. For example, the connector arrangement may be of multipart form, each part forming, for example, one of the contact regions and the associated intermediate region, the parts together forming the terminal region. The invention may also be used in other applications.

Claims

CLAMMS

1. An electrical contact arrangement comprising a contact element having a terminal region, first and second contact regions, the first and second contact regions being, in use, substantially co-planar, and first and second intermediate regions interconnecting the first and second contact regions, respectively, and the terminal region, the first and second intermediate regions each being upstanding from the plane of the first and second contact regions.

2. An electrical module comprising a substrate upon which an electrical component is mounted, a terminal, and a contact arrangement providing an electrical connection between the terminal and the electrical component, the contact arrangement comprising a contact element having a terminal region connectable to the terminal, first and second contact regions which lie substantially in the same plane as one another, and first and second intermediate regions interconnecting the first and second contact regions, respectively, and the terminal region, the first and second intermediate regions upstanding from the plane of the first and second contact regions and being arranged, in use, to transmit a compressive load to the contact regions to urge them toward the electrical component.

3. An arrangement according to Claim 2, wherein the first and second contact regions extend parallel to one another.

4. An arrangement according to Claim 2 or Claim 3, wherein the first and second contact regions lie on opposite sides of a plane containing the first and second intermediate regions.

5. A module according to any of Claims 2 to 4, wherein the electrical component comprises a diode.

6. A module according to any of Claims 2 to 5, wherein the module incorporates several such electrical components and associated contact arrangements.

7. A module according to any of Claims 2 to 6, wherein the contact element comprises a resilient copper materiaL 8. A module according to Claim 7, wherein the resilient copper material is beryllium copper.

9. A module according to any of Claims 2 to 8, wherein the contact regions are soldered to the electrical component.

10. A module according to Claim 9, wherein the cntact regions are soldered to the electrical component using a gold/tin solder.

11. A module according to any of Claims 2 to 10, wherein the contact arrangement includes a third contact region and associated third intermediate region.

12. An electrical generator comprising a rotor rotatable relative to a stator, and at least one module according to any of Claims 2 to 11 serving to form a rectifier arrangement for the output of the generator.

13. A module substantially as hereinbefore described with reference to the accompanying drawings.