FR2465345A1 - ELECTRIC GENERATOR AS THREE-PHASE ALTERNATOR WITHOUT COLLECTOR RING - Google Patents

Abstract

A. ELECTRICAL GENERATOR, IN PARTICULAR THREE-PHASE ALTERNATOR WITHOUT COLLECTOR RING, PROVIDED WITH A FIXED OUTPUT WINDING AND A PRODUCTION DEVICE WITH A ROTATING EXCITATION FIELD INCLUDING A MAGNETIC CIRCUIT 17, 18, 19 AS WELL AS A WINDING EXCITATION 22, THE MAGNETISABLE CIRCUIT INCLUDING, EXCLUDING ELEMENTS WITH SOFT MAGNETIC MATERIAL 17, 19 ALSO AT LEAST ONE ELEMENT CONSISTS OF HARD MAGNETIC MATERIAL 15, 16. B. CHARACTERIZED IN THAT THE SHAFT 15, 16 OF THE GENERATOR IS USED AS PART OF MAGNETIC MATERIAL 15, 16. C. GENERATOR APPLICABLE TO MOTOR VEHICLES.

Description

1, - The invention relates to a generator

  including three-phase alternator without collar

  reader, provided with a fixed output winding and a

  positive output of a rotating excitation field and comprising a magnetic circuit and an excitation winding, the magnetisable circuit including, apart from elements with a soft magnetic material, also at least one element

  made of hard magnetic material.

  In electric generators with self-excitation, it always intervenes the difficulty concerning the establishment of an excitation field. When the material

  the magnetisable circuit used in the excitation circuit, is a

  the magnetic induction is very low, the residual induction is very weak, and after its start, the generator or does not get excited at all, or only excited for high speeds of rotation. It is already known to carry out the excitation of three-phase alternators used on motor vehicles by passing through the excitation circuit, a pre-excitation current once the ignition switch has been actuated, and by intermediate of a resistor or control lamp

charge.

  It is already known to improve

  the excitation, thus the behavior at startup, of the gen-

  by introducing further magnets into the excitation circuit at a suitable place, in particular between the claws of three-phase alternators provided with rotors with pins

with claws.

  These known arrangements, however, have the disadvantage of a certain complexity - and expense - of

  mounting or the disadvantage of low mechanical strength.

  In any case the costs to bear are in adverse relationship

with the result obtained.

  The generator according to the invention is characterized in that its shaft is used as an element to

hard magnetic material.

  Vis-à-vis the known achievements, it has the advantage that the cost of its manufacture is very low and the excitation of the generator is ensured in all cases. There is no need for mounting means outside the 2. generator itself. Another advantage is to see that the manufacture of the generator does not require any element

  additional construction for the excitation device.

  The invention provides modes of advantageous arrangements and improvements of the generator as

defined above.

  It is particularly advantageous that the space volume of the generator is not found

  enlarged and that no disturbing elements are used.

  In addition, it is possible to obtain a mechanical resistance

  high and good magnetic properties.

  The invention will be better understood using

  of the following description and the accompanying drawing showing a

  embodiment of the invention.

  - The single figure of this drawing is a schematic view, partially in section, of a three-phase alternator free of slip ring, o are found all the

  separate arrangements mentioned in the description.

  In a pot-shaped generator housing provided with two flanges 11 and 12, a rotor shaft 15 is mounted in the bearings 13 and 14. The rotor shaft 15 has a middle portion 16 representing a larger diameter. This middle portion 16 carries a first pole wheel 17. To this first pole wheel 17 is connected, via a non-magnetic ring 18, a second pole wheel 19, which is

  therefore not directly attached to the rotor shaft 15.

  The flange 11 located on the side of the driver

  1 carries a holding device 21, to which is fixed an excitation winding 22. In the parts of the housing 11 and 12

  which serve as flanges is inserted a stator-23, carrying a coil

  As a result of this output winding 27, a rectifier 24 which, outside the charging current, also supplies the excitation current, via a voltage regulator, has been connected. 25. The current supply is via the cable 26. The pole wheels 17, 19

have claws 31.

  It can be seen from the figure of the drawing that the middle part 16 in full and the remaining part of the

  rotor 15 partially, are placed in the magnetic flux

  than in series with the soft magnetic material elements that are

the pole wheels 17, 19.

3.-

  Three materials were particularly

  very favorable for use in constituting the elements 15, 16, therefore the rotor shaft 15 with its middle portion 16, namely: carbon-hard hard steel, worked and treated in the usual manner, steel of alloy cementation, low in carbon, for example MnCr 5 (manganese chromium alloy), hardened by quenching without being carburized and subjected to a higher tempering treatment than in the past, - carburizing steel in alloyed form,

  Example C15, hardened by being cemented and quenched.

  As an exemplary embodiment, a three-phase alternator without a slip ring, as used to operate on motor vehicles, has been chosen. The

  However, the arrangements described may also find their application

  cation without other in the case of a generator provided with

slip rings.

4.-

Claims (8)

  1.- Electric generator, in particular three-phase alternator without slip ring, provided with a fixed output winding and a device for producing a rotating excitation field and comprising a magnetic circuit (17, 18, 19 ) and an excitation winding (22), the magnetisable circuit including, apart from elements with a soft magnetic material (17, 19), also at least one element made of hard magnetic material (15, 16), characterized in that what the shaft (15, 16) of the generator is used as   element made of hard magnetic material (15, 16).   2. Generator according to claim 1, characterized in that at least one of the hard magnetic material elements (15, 16) is placed in the magnetic flux   in series with the elements with soft magnetic material (17, 19).   3. Generator according to one of the   cations 1 and 2, characterized in that the rotor shaft (15)   has a middle part (16) of larger diameter.   4. Generator according to claim 3, characterized in that the median portion (16) is dimensioned so as to serve at the same time as the core of the excitation device. 5.- Generator according to any one   Claims 1 to 4, of the type comprising claw bosses,   characterized in that the middle portion (16) carries the wheels polar (17, 19).   6.- Generator according to any one of   Claims 1 to 5, characterized in that a steel rich in   Carbon is used as a hard magnetic material.   7.- Generator according to any one of   Claims 1 to 5, characterized in that a steel of   tation & bonded to the hardened state is used as the hard magnetic material and at least one of the corresponding elements (15, 16) is subjected to further processing of income qu'usuellement.   8.- Generator according to any of the   Claims 1 to 5, characterized in that a cement steel   non-alloy is used as a magnetically hardened material and at least one of the corresponding elements (15, 16)   is hardened by being case hardened and tempered.