WO2007065929A1

WO2007065929A1 - Connecting of exciter coil to the rectifying means

Info

Publication number: WO2007065929A1
Application number: PCT/EP2006/069441
Authority: WO
Inventors: Cyril Moya
Original assignee: Thales
Priority date: 2005-12-07
Filing date: 2006-12-07
Publication date: 2007-06-14
Also published as: FR2894408B1; FR2894408A1

Abstract

The invention relates to the connecting of the exciter of an electric machine. The invention is particularly suited to a synchronous electric machine used as a generator. The electric machine comprises a rotor comprising at least one exciter coil and means for rectifying a current generated by the coil. The coil and the rectifying means are connected together with the help of at least one rigid linking piece (50). An output wire of the exciter coil is brazed to the linking piece (50). The linking piece (50) is connected in a removable manner to two input points of the rectifying means and is incorporated with the coil.

Description

CONNECTION OF EXCITATOR COIL TO RECTIFICATION MEANS

The invention relates to the connection of the exciter of an electric machine. The invention is particularly suitable for a synchronous electric machine used as a generator, an example of an electric diagram of which is given in FIG. 1.

This type of machine comprises a rotor 1 and a stator 2. The rotor 1 comprises an inductor 3 supplied with direct current. The direct current is generated by a rectifier bridge 4 supplied by an exciter 5. The invention relates to the connection between the exciter 5 and the rectifier bridge 4. The exciter is three-phase, according to the example presented. The exciter is formed by three windings 6, 7 and 8, the first ends of each of which are connected at a common point 9. Second ends 10, 11 and 12 of each winding, respectively 6, 7 and 8, are connected to diodes 13 to 18 of the rectifier bridge 4. More precisely, the end 10 is connected to the anode of the diode 13 and to the cathode of the diode 14. The end 11 is connected to the anode of the diode 15 and to the cathode of the diode 16. The end 12 is connected to the anode of the diode 17 and to the cathode of the diode 18. The cathodes of the diodes 13, 15 and 17 are connected to a first end 19 of the inductor 3 and the anodes of the diodes 14, 16 and 18 are connected to a second end 20 of the inductor 3.

The stator 1 comprises a main excitation winding 25 supplied with direct current by its terminals 26 and 27 as well as an armature 28 formed by three windings 29, 30 and 31 delivering an alternating current.

The diodes 13 to 18 are for example fixed on a magnetic circuit of the exciter 5. Each diode has a threaded rod forming the terminal on which the wires of the windings 10, 11 and 12 of the exciter 5 are connected. An attempt has been made to connect the wires of the windings 10, 1 1 and 12 to the threaded rods by means of lugs crimped onto the wires of the windings 10, 1 1 and 12. The lugs each have a circular opening each inserted on one of the rods threaded. The lugs are held in position on the threaded rods by nuts. The shaping of the crimping of the terminals on the wires is a very delicate manual operation. It is indeed necessary to cut the wires to a precise length relative to the winding, to isolate the parts of the wires before crimping to give a precise shape to each wire and then finally to crimp. The length and the shape given to the wires is important to avoid any imbalance during the rotation of the rotor 1. An example of crimping the terminals on one of the wires, for example 10 is given in FIG. 2. The wire 10 is formed by two conductors 10a and 10b each crimped into a terminal, respectively 35 and 36. To ensure an equipotential connection between the terminals 35 and 36, it is necessary to add a conductor 37 whose ends are each crimped into one of the terminals 35 and 36. An insulator 38 is wrapped around the conductors 37 and 10a from the point 39 of crimping on the terminal 35 to an outlet 40 of the conductors 10a and 10b of the winding 6. Similarly an insulator 41 is wrapped around the conductors 37 and 10b from the crimping point 42 on the terminal 36 to the outlet 40. A heat-shrinkable sheath 43 insulates the crimping point 39 and a heat-shrinkable sheath 44 insulates the point 42.

The invention aims to simplify the connection of the output wires of the exciter windings to the diode bridge by eliminating in particular the conductor 37. The invention aims to limit the number of manual operations in the connection.

To this end, the subject of the invention is an electric machine comprising a rotor comprising at least one excitation coil and means for rectifying a current generated by the coil, characterized in that the coil and the rectification means are connected between them using at least one rigid connection piece, in that an output wire of the excitation coil is soldered on the connection piece, in that the connection piece is removably connected at two points input rectifying means and in that the connecting piece is incorporated in the coil.

By having a connection piece that can be produced in series between the winding wires and the diodes, the connection of the exciter is carried out much more quickly and its reproducibility is improved.

The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, description illustrated by the attached drawing in which: Figure 1, already described above, shows an example of an electrical diagram of an electrical machine to which the invention can be applied;

FIG. 2 represents an embodiment of the connection between a winding of an exciter and two diodes of a rectifier bridge;

Figures 1 and 2 have already been described to introduce the invention; Figure 3 shows a connection piece according to the invention;

Figures 4 and 5 show the mounting of the connection between an exciter and a diode bridge;

Figure 6 shows in perspective the mounting of three connection pieces;

Figure 7 shows in perspective the connection piece incorporated in the coil.

For the sake of clarity, the same elements will have the same references in the different figures.

In an electric machine according to the invention, the wires of the windings 10, 1 1 and 12 of the excitation coil are no longer connected to the threaded rods of the diodes 13 to 18 only by crimp terminals on the wires 10, 1 1 and 12 The connection is made by means of a rigid connection piece 50 shown in FIG. 3.

The connecting piece 50 is advantageously made from a cut sheet. The connection piece 50 has a semi-circular part 51 around an axis 52. The plane of the sheet from which the connection piece is cut is perpendicular to the axis 52. Once mounted on the exciter, the axis 52 is coincident with an axis of a rotor of the electric machine. One or more notches 53 are formed in the semi-circular part 51. The notches 53 make it possible to solder the output wire or wires of the excitation coil such as for example the wires 10a and 10b.

The semicircular part 51 has two ends 54 and 55 advantageously extended by two arms respectively 56 and 57 each ending in a ring respectively 58 and 59 making it possible to connect two entry points of the straightening means.

The connecting piece 50 is advantageously covered with an insulator, shown hatched in FIG. 3, with the exception of the zones allowing connection such as notches 53 and rings 58 and

59.

Advantageously, the arms 56 and 57 each comprise an elastic zone respectively 60 and 61 making it possible to accept deviations in the positioning between the straightening means and the exciter. The elastic zones 60 and 61 also allow the expansion of the arms which occurs during the rotation of the rotor of the electric machine. The elastic zones 60 and 61 are for example formed by U-shaped folds of the sheet, called grooving, of the arms 56 and 57 moving away from the plane of the semicircular part 51.

In FIG. 3, beyond the silks 60 and 61, the arms 56 and 57 are folded away from the plane of the semi-circular part 51 to allow the mounting of the rings 58 and 59 on threaded rods forming points connecting the rectifier bridge 4.

The connecting piece 50 advantageously comprises a folding

62 located near the notches 53. The folding 62 allows the nesting of several connection pieces as shown in FIG. 4.

FIG. 4 represents in top view, an excitation coil on which a rectifier bridge has been assembled comprising six diodes 13 to 18 each located on a radius around the axis 52 of the rotor. The spokes are substantially angularly spaced 60 °.

5 shows in partial section in a plane containing the axis 52 the excitation coil shown in Figure 4. In Figure 5 appears the connecting piece 50 with its semicircular part 51, one of the arms 56 terminated by the ring 58 which is crossed by a threaded rod 65 belonging to the diode 14. The locking of the ring 58 on the diode 14 is obtained by a nut 66 coming to be screwed on the threaded rod 65.

FIG. 6 makes it possible to view in perspective the mounting of three connection pieces 50 regularly arranged around the axis 52. With respect to FIG. 3, an additional fold is produced in each arm 56 and 57. These folds are produced at the time mounting rings 58 and 59 on threaded rods 65.

Figure 6 allows to view in perspective the assembly of the connecting piece 50 and a coil 70 for example formed of the three windings 6, 7 and 8 arranged inside a magnetic circuit 71 formed of an assembly of sheets. The connection pieces 50 are incorporated into the coil 70. In other words, the connection parts are an integral part of the coil 70. This structure has the advantage of withstanding mechanical forces well when the coil 70 is in rotation. Tests have been carried out at more than 20,000 revolutions per minute. The mechanical strength of a connection piece forming part of the coil is much better than an attached or removable connection piece.

Advantageously, the coil 70 and the connection pieces 50 are laced together. During the production of the coil 70, the wires which compose it are wound in the magnetic circuit 71. Buns 72 formed of winding wires project beyond the magnetic circuit 71. To ensure good rigidity of the coil 70, the updos by means of a tape 73 resistant to mechanical stress and to the internal temperature of the electric machine in use. For example, a Nomex brand ribbon manufactured by the Dupont de Nemours company based in the United States of America will be used. After lacing the connection piece 50 and the coil 70, an impregnation of the assembly is practiced by means of a varnish making the assembly homogeneous. Advantageously, the semi-circular part 51 of each connection piece 50 is laced with the wrap 70.

Claims

1. Electric machine comprising a rotor comprising at least one excitation coil and rectifying means (13 to 18) of a current generated by the coil (70), characterized in that the coil (70) and the rectifying means ( 13 to 18) are connected to each other using at least one rigid connection part (50), in that an output wire (10a, 10b) of the excitation coil is soldered to the connection part ( 50) in that the connection piece (50) is removably connected to two entry points (13, 14) of the straightening means (13 to 18) and in that the connection piece (50) is incorporated to the coil (70).

2. Electric machine according to claim 1, characterized in that the connection piece (50) is made of a cut sheet.

3. Electric machine according to claim 1, characterized in that the connection piece (50) comprises a semi-circular part (51) around an axis (52) coincident with an axis of the rotor, and in that the wire output (10a, 10b) of the excitation coil is soldered to the connection piece (50) in a notch (53) formed in the semi-circular part (51).

4. Electric machine according to one of the preceding claims, characterized in that the coil (70) and the connection piece (50) are laced together.

5. Electric machine according to claims 3 and 4, characterized in that the semi-circular part (51) is laced with the coil.

6. Electric machine according to one of the preceding claims, characterized in that the semi-circular part (51) has two ends (54, 55) extended by two arms (56, 57) each ending in a ring (58, 59) for connecting the two entry points of the straightening means (13 to 18).

7. Electric machine according to one of the preceding claims, characterized in that the entry points of the straightening means (13 to 18) comprise threaded rods (65).

8. Electric machine according to claims 6 and 7, characterized in that one of the rings (58, 59) is assembled on one of the threaded rods (65) by means of a nut (66).

9. Electric machine according to one of the preceding claims, characterized in that the connection piece (50) is covered with an insulator with the exception of zones (53, 58, 59) allowing the connection.

10. Electric machine according to one of the preceding claims, characterized in that the arms (56, 57) each comprise an elastic zone (60, 61) making it possible to accept deviations in the positioning between the straightening means (13 to 18) and the exciter.