FR2485287A1 - DC or rectified AC motor - has two cylindrical rotor sections with longitudinal notches cut between pole faces - Google Patents

Abstract

The DC or rectified AC motor includes a cylindrical rotor on a shaft with three pairs of stator poles directed inwards towards it. The stator poles are in pairs, one of each pair being adjacent to one part of the rotor, whilst the other pole of the pair is adjacent to the second part of the rotor. The rotor has a series of notches cut parallel to the axis of the cylinder, with uncut projections forming the cores on which coils are wound. The coils are connected to two collecting rings at one end of rotor shaft. Diodes mounted in a bridge circuit are connected in parallel with the commutator between the supply terminals feeding current to the machine, and the connections for the stator windings. Where there is a north pole on one section of the rotor, there is a south pole on the adjoining section of the rotor, the two poles interacting with the corresponding two poles of a stator section.

Description

1a present invention relates to a rotating electrical machine, motor or generator, direct current or rectified alternating current.

 This electric machine allows the conversion of electromagnetic forces into rotary movement or, conversely, the production of electric energy from a rotary drive movement.

 The invention relates, more particularly, to the production of an electric motor of simple and robust construction, in particular as regards the windings and the carcass elements. This motor, with variable speeds from 1500 to 10000 revolutions / minute, gives all satisfaction from the point of view of switching, its characteristics allowing it a multitude of industrial applications, in particular: vehicle traction, pumping stations, variators of frequencies or commutatriced.

 More particularly, the present invention can be considered as an improvement of the rotary electric DC machine, the subject of the previous French patent application NO 79 08 167 of the applicant.

 It is recalled that this machine comprises a rotor whose paddles, in even number, have invariable polarities, alternately "North" and "South", and a stator whose blades, in number greater than those of the birotor, are magnetized by coils all connected together. These are aligned by a switching device formed on the one hand by a set of alternately positive and negative conductive lamellae, in the same total number as the rotor blades, separated and electrically isolated from each other by neutral lamellae. All these strips are carried by a cylindrical support wedged on the rotor shaft, and the conductive strips are electrically connected to slip rings also carried by the rotor shaft.

-On the other hand, by a set of brushes cooperating with the aforementioned lamellae and electrically connected to the connection points between the stator coils.

 According to other characteristics described in the applicant's earlier patent application, considered here - In the case where the rotor is of the wound type, its magnetizing coils are supplied, like the conductive lamellae of the switching device, from worn slip rings by the tree, and preferably this supplied via a rheostat.

-The connection points between the stator coils are connected to the corresponding brushes, cooperating with the switch slats, via resistors.

 -Capacitors are mounted between two consecutive brushes of the switch, in parallel with the stator coils.

-The brushes of the switching device are carried by a rotating mounted disc provided with means for modifying its angular position, to vary the speed and the direction of rotation of the motor.

 The present invention aims to improve the performance of such an electric motor, and to permanently eliminate sparks and deterioration in contact between the brushes and the lamellae of the control device.

 For this purpose, it is provided according to the present invention that the rotor is cylindrical and has at its periphery notches distributed in groups corresponding to the number of rotor blades and separated by regions without notches, said notches receiving the windings of coils connected to slip rings carried by the shaft, and that, on the stator, diodes mounted in Graetz bridge are interposed, bypassing the switching device, between the DC or rectified power supply or output terminals of the machine, and the connection points between the stator coils.

The gold rot of this electric whirling machine has notches in which it is easy to insert and block the conductors of the coils, and these notches are distributed in groups separated by regions W without notches, therefore smooth, which correspond to polar expansions These smooth regions each occupy for example, in the case of a bipolar rotor re, an angle of the order of 200, while the two groups of notches each extend over an angle of approximately 1600 between the two blades. for rotors of large diameter, for example greater than 300Eggles pale and the groups of notches are more numerous and occupy smaller angles; the number of rotor poles always remains even, for example 4.6 or 8 blades, and the switch comprises in all cases a number of conductive lamellae equal to the number of poles of the ro turn,
According to an advantageous characteristic, the rotor is formed of two or more cylindrical elementary rotors, wedged on the same shaft, and magnetically isolated from each other, each blade "Nords of an elementary rotor being located opposite a blade '- South "of the neighboring elementary rotor, and vice versa; the arrangement of the polar masses of the stator corresponds in the axial direction, with the division of the rotor into two or more elementary rotors.

Thus, the rotor can be formed of two elementary rotors identical in size, but of alternating polarities, while the stator comprises polar masses in "U" giving, in the axial direction, double blades.

 One can also provide a rotor formed by three elementary rotors, this in combination with a stator which comprises polar masses in "E" giving, in the axial direction, triple poles. In the latter case, preferably, the central elementary rotor will have a length twice that of each of the two extreme elementary rotors. In all cases, the axial distribution of the stator blades will be complementary to that of the rotor poles.

 It should be noted that the polar masses of the stator do not have to be magnetically connected to each other, in the direction of the circumference of the stator. It is therefore advantageous to use polar masses extending along a generatrix, that is to say parallel to the shaft, but separated from each other, and fixed individually, for example by bolting, inside of a molded hard plastic casing. This offers qualities of lightness, insulation, ease of obtaining the desired shapes, and it especially avoids overheating due to variations in the magnetic field producing induced currents, in the case of the usual metal carcasses.

The diodes mounted in Graetz bridge, which are another fundamental characteristic of the invention, are connected to the connection points grouping together the terminals of the static coils, the resistors connecting these coils to the brushes of the switch, and the capacitors mounted between these brushes. The rectified direct current outputs of the diode bridge are connected to the machine terminals, according to their polarity.

The function of these diodes is to allow the effective recovery of the breaking extra-currents: the overvoltage currents, resulting from the switching and more precisely from the passage of the brushes from a conductive strip under tension to a neutral strip of the switch, are thus absorbed and rectified by the diodes mounted in Graetz bridge, and brought back to the motor supply terminals, without unbalancing the assembly.

The action of these diodes, combining with the resistors and capacitors already known per se and mentioned above, makes it possible to obtain perfect switching, and allows the stator to use coils comprising numerous turns. This type of coils, economical in energy consumption, does not heat up, and accepts without damaging large overvoltages, the cut-off taking place when they receive the maximum magnetic flux coming out of the rotor pins; on the other hand, have a high impedance.

According to an additional characteristic, the ohmic value of each resistance, connecting a connection polish between the coils of the stator and a brush of the switch, is twice the internal resistance of the diodes mounted in Graetz bridge.

Each diode of this Graetz bridge must be rectifier of a current double of the intensity admitted in the coils connected in series of a polar stator mass in "E" or in 'U n. The value of its reverse voltage must be at least about five times greater than the maximum voltage allowed at the machine terminals.

The stator has at least three ptles. In the case of a stator with a higher number of blades and in even number, each brush of the switch feeds in parallel the stator coils mounted on polar masses diametrically opposite, but in circuit " crossed ", so that the polarity of two diametrically opposite polar masses is" North for one, and ". South "for the other. Based on this principle, two modes of connection of the stator coils are possible.
According to a first possibility, if it is considered that the blades are divided into two groups of blades, of the same number, which alternate with each other, two diametrically opposite poles always belonging to two distinct groups, it is provided that in each group the connection point of a stator coil input, with the conductor connecting this coil to a brush of the switch, coincides with the output point of the stator-previous coil. Thus all the stator coils are connected to each other and form a crown.

 This mode of connection of the stator coils allows, in the two groups of poles, to put each stator coil in turn in direct circuit between two brushes of different polarity, or in series with the previous stator coil. Thus we obtain rotating fields generating variable electromagnetic forces, which exert a driving torque on the polarized magnetic flux enveloping the rotor. Each stator pole mass also exerts an electromagnetic force on the conductors of the rotor, following an arc of its periphery of an angular value of 1600 for example, before the brush reaches the neutral strip. The stator coil, being then more supplied by the brush considered, reverses its magnetic flux, hence magnetic reactance on the polar expansion facing it. The over-current of the extra-currents created by the breaking of the motor terminals through diodes mounted in Graetz bridge, since the resistor mounted in series with the brush has an ohmic value twice that of the diode; the capacitor mounted in bypass has the role of clipping the overvoltage peaks, thus protecting the proper functioning of the diode.

According to a second possibility of connection concerning the stator coils, the inputs of two coils in parallel, mounted on polar masses diametrically opposed, are united at the same connection point connected to a brush of the switch and to the diodes mounted in Graetz bridge, and the outputs' of all the stathric coils are connected on a common circular conductor.

 For each pair of diametrically opposite poles, connected in parallel, the directions of the coils turns are reversed to respect the direction of magnetic flux output giving poles respectively "North" and South ". It should be noted that in this type of connection the stator coils are always in series each with the neighboring coil, and that, as in the case of the first connection mode, the breaking and self-induction extra-currents are absorbed and rectified by the diodes mounted in Graetz bridge, and brought back to the machine terminals.

In any case, the invention is better understood with the aid of the description which follows, with reference to the appended diagrammatic diagram showing, by way of nonlimiting examples, some embodiments of this rotary direct current electric machine , or with rectified alternating current
Figure 1 is a longitudinal sectional view of u, n electric motor according to the invention;
Figure 2 is a perspective view showing the rotor and the stator pole masses of this motor;
Figure 3 is a detail view, in perspective, of one of the stator pole masses;
Figure 4 is a very schematic cross-sectional view of the motor according to Figures 1 to 3, in a first connection mode;
Figure 5 is a complete electrical diagram of the engine circuits, corresponding to the connection mode of Figure 4;
Figure 6 is a cross-sectional view similar to Figure 4, but illustrating a second method of connection;
Figure 7 is a perspective view similar to Figure 2, showing another embodiment of the rotor and the stator pole masses.

 The electric motor, the mechanical structure of which appears in FIGS. 1 to 3, generally comprises a multipolar rotor 1 wedged on a non-magnetic shaft 2, for example in bronze, and rotating inside a stator 3. The latter comprises a cylindrical carcass - 4, made of molded hard plastic material, and closed at its two ends by flanges 5 and 6 which carry the bearings, respectively 7 and 8, in which the shaft 2 rotates, the two ends of which protrude from the outside. The carcass 4 also includes a mounting base 9, allowing the mounting of the motor on any support, not shown (see more particularly Figure 1).

 In the embodiment considered here, the rotor 1 is bipolar and double, that is to say that it consists, as shown in FIGS. 1 and 2, of two identical elementary rotors 10 and 71 of generally cylindrical shape, produced in silicon stacked plates, keyed onto the shaft 2 and separated axially from one another by a spacer ring 12, made of non-magnetic material such as bronze.

 Each elementary rotor 10 where 11 has trapezoidal notches, respectively - 13 and 14, distributed in two groups which are separated by regions 15 and 16 devoid of notches, therefore having a smooth cylindrical surface. Each group of notches 1.3 or 14 extends at an angle 0 <of about 1600, so that the two regions 15 or 16 devoid of diametrically opposed notches each occupy, on each elementary rotor 10 or 11, an angle of the order of 200. All the notches 13 and 14 receive electrical conductors 17, the arrangement of which is best shown in FIGS. 4 and & the said notches being provided in even number in each group so as to respect the balancing at the same time mechanical and electromagnetic of the rotor 1. The electrical conductors 17 form, on each elementary rotor 10 or 11, a magnetizing coil, and the two coils are arranged and supplied in such a way that the regions 15 and 16.

without notches of the respective elementary rotors 10 and 11 form a "North" pole and a "South" pole, diametrically opposite and alternating; more specifically, the "North" pble of the elementary rotor 10 is located opposite the ".Sud" pole of the elementary rotor 11, and conversely the "South" pole of the elementary rotor 10 is located opposite the "" North "pole of the rotor elementary 11.

The "V" distribution of the rotor windings, clearly visible in FIG. 6, facilitates their insertion into the notches 13 and 14 located on each side of the blades, and the trapezoidal shape of the notches allows the turns to be locked by an insulating keying 18 .

 As shown in FIGS. 1, 2 and 5, the shaft 2 carries, near one of its ends, first slip rings 19 and 20 which are connected to the conductors 17 housed in the respective notches 13 and 14 of the two elementary rotors 10 and 11. These rotating rings 19 and 20 are supplied with direct current, with opposite polarities, by respective brushes 21 and 22, one of which is connected in series with a rheostat 23 which makes it possible to varying the electromagnetic field of the rotor 1.

In the case considered here of a bipolar rotor 1 ", the stator 3 comprises either cross blades, or preferably six poles (indicated in this case by the Roman numerals I to VI), distributed at constant angular intervals inside the carcass 4, and electrically and magnetically isolated from each other. For the clarity of the drawing, FIG. 1 shows only the three blades I, II and III, separated by angular intervals of 1200, and in FIG. 4 the three other blades
IV, V and VI are only partially represented.

 In correspondence with the division of the rotor 1 into two elementary rotors 10 and 11, each of the six stator poles I to VI 'comprises a polar mass in' lU ", shown isolated in FIG. 3, with an allocated sole 24 extending in the direction of the shaft 2, sole on which are mounted two identical blocks 25 and 26 which end in pole shoes situated, respectively, opposite the two elementary rotors 10 and 11. Each block 25 or 26 comprises threads 27, corresponding to holes 28 in the sole 24, and making it possible to fix both the block against the sole 24 and the assembly to the carcass 4, by means of screws not shown. The three parts 24, 25 and 26 constituting each stator polar mass can be produced in molded ferrite, with high magnetic permeability and allowing, thanks to a coercive field and an almost zero hysteresis, an almost instantaneous reversal of the magnetic flux, an important property for rota speeds Alternatively, the polar masses of the stator can also be produced in laminated, cut or folded sheet.

The magnetizing coils of the six stator blades
I to VI, designated respectively by the references 29 to 34, are supplied by a switching device indicated as a whole by 35 and arranged, on the shaft 2, of the block opposite the slip rings 19 and 20 already mentioned, to which are added two other similar slip rings 36 and 37.

 The switch 35 comprises, for a bipolar rotor, two conductive strips 38 and 39, mounted on a common support 40 in the form of a disc wedged on the shaft 2, and separated from one another, mechanically and electrically, by two strips diametrically opposed neutrals 41. The conductive strip 38 is electrically connected to the collectric ring 36, supplied for example under the continuous "less" polarity, by a brush 42, while the conductive strip 39 is electrically connected to the collector ring 37, supplied for example under the polarity continues "plus", by another brush 43, so that a negative strip 38 and a positive strip 39 are obtained. These two conducting strips 38 and 39 each cover an angle ss equal for example to 1600 (see FIG. 4) , at the periphery of the disc 40, so that the neutral strips 41 each cover an angle of 20 in the example considered. While Figures 1,2 and 4 give a schematic but exact representation of the configuration of the elements of the switch 35, Figure 5 shows the latter under a strong developed (the two ends being in reality a single point).

The switch 35 also comprises three brushes 44, 45 and 46; distributed at angular intervals of 1200 on a support disc 47 (see FIG. 1), and cooperating with the lamellae 38, 39 and 41. The support disc 47 is shown rotating around a hub 48 secured to one of the flanges 5 and coaxial with the shaft 2; its angular position is adjustable by means of a radial rod 49 which passes through the carcass 4 by a light to end, outside, by a handle 50, which makes it possible to vary the angular position of the brushes 44, 45 and 46 compared to stator blades
I to VI. Simple means, not shown, can also be provided to limit the rotation of the support disc 47, to immobilize the latter in a determined angular position, and to return it to its average position.

 Each of the brushes 44, 45 and 46 is electrically connected, via a resistor, respectively 51.52 and 53 (see FIGS. 4.5 and 6), to one of three connection points, respectively 54, 55 and 56, located between the stator coils 29 to 34, the mounting of which is carried out according to a general arrangement '1 in current ne', which will be specified below. The three connection points 54, 55 and 56 are also connected to one another by capacitors 57, 58 and 59 mounted in a loop.

In the connection mode of FIGS. 4 and 5, the six stator poles I to VI t have their respective coils 29 to 34 mounted in the following manner (see above all the complete developed diagram given by FIG. 5, taking into account which FIG. 4 gives details only for three of the p8les) - The coil 32 is mounted in parallel with the diametrically opposite coil 29, between points 54 and 55.

- The coil 33 is mounted in parallel with the diametrically opposite coil 30, between points 55 and 56.

- The coil 34 is mounted in parallel with the diametrically opposite coil 31, between points 56 and 54.

The directions of windings of all these stator coils are also chosen such that two diametrically opposite blades are always one "North", and the other -1 'South
In the connection mode of FIG. 6, somewhat different from the previous one, the respective coils 29, 30 and 31 of the blades I, II and III have a terminal connected directly to one of the aforementioned connection points, respectively 54.55 and 56, while the other terminals of these three coils 29, 30 and 31 are all interconnected by a common circular conductor 60. The respective coils 32, 33 and 34 of the blades IV, V and VI, diametrically opposite to the previous ones, have a terminal connected (by the conductors drawn in dotted lines) to one of the aforementioned connection points, respectively 54, 55 and 56, while the other terminals of these three coils 32, 33 and 34 are also all connected to the circular conductor 60 already mentioned.

 As before, two diametrically opposite blades, such as those I and IV, here again, are one "North" and the other "South", taking into account the connections and winding directions of the stator coils 29 to 34 .

 In the two connection methods described above, and according to an essential characteristic of the present invention, the three connection points 54, 55 and 56 are connected to a set of six diodes 61 to 66 mounted in n Graetz bridge "( see Figures 4, 5 and 6. The "rectified current n" outputs of this diode bridge are connected by two conductors 67 and 68 to the DC supply terminals, one "positive" and the other "negative" , which are also connected to the four slip rings 19, 20, 36 and 37.

 The DC power supply circuit further comprises two protective diodes 69 and 70, interposed on its branch sabramentent stator 3, that is to say its branch connected to the slip rings 36 and 37 and the bridge diodes 61 to 66.

Finally, an inverter switch 71 with a special arrangement is inserted on this DC power supply circuit. -Two first contacts of this inverter switch 71 are provided on the conductors leading to the brushes 21 and 22, to allow the direction to be reversed. supplying the conductors 17 and 18 of the rotor 1, which corresponds to an inversion of the direction of rotation of the motor. A capacitor 72, interposed between the two fixed contacts supplying the rotor, here makes it possible to attenuate the deterioration of the contacts by the electric arcs.

-Two other contacts of this reversing switch 71 are provided on the conductors leading to the brushes 42 and 43 therefore to the stator 3; these other contacts interrupt the supply of the stator 3 during the reversal operated by means of the first two contacts, but they themselves do not perform any reversal function, that is to say that the polarities of the slip rings 42 and. 43 remain unchanged. The direction of the current in the coils 29 to 34 of the stator therefore always remains the same.

To understand the operating principle of the electric motor which has just been described, one can first refer to FIG. 2, showing how the magnetic flux closes in a particular relative angular position of the rotor 1 and of the stator 3, as well as in Figures 4 and 6, which allow to follow the effects produced at one of the elementary rotors.

The effects obtained at the level of the other elementary rotor 11 are similar, except for the polarities. In general, magnetic fields, rotating fields, are obtained, the electromagnetic forces of which exert an engine torque effect on the flow leaving the conductors 17 of the rotor 1.

The angular offset of the disc 47 carrying the brushes 44, 45 and 46, controlled by the rod 49, makes it possible to adapt the operating conditions, in particular
- An angular offset towards the rear of the axis of each brush relative to the corresponding stator blade, for example 300, makes it possible to obtain a high torque at start-up, for a reduced speed of the rotor, since the blades of the rotor are then subjected to two forces, one repulsive, the other attractive, from the six stator blades.

- By choosing an angular offset towards the front of the axis of each brush ~ relative to the corresponding stator blades, for example 200, we obtain high speeds of rotation, by correcting the deformations of the lines. magnetic flux leaving the rotor 1.

 The rheostat 23, mounted in series with the coils of the rotor 1, also makes it possible, by varying the magnetic flux leaving the rotor blades, to act on the motor torque and on the speed of rotation (or to regulate the voltage, when the same rotating machine operates as a generator of direct or rectified current or three-phase alternating current).

 The switching problems being solved by the invention, in particular thanks to the diode bridge 61 to 66, the wear of the elements of the switch 35 becomes negligible, and this allows the use of high quality coals for the brushes. The mechanical and electrical assembly is robust and easy to maintain or repair, in particular the stator poles are easily interchangeable, as are the elementary rotors 10 and II keyed onto the shaft 2. The construction of the assembly is simple, and in particular the carcass 4 and the flanges 5 and 6, which can be produced in plastic material or in another insulating material, allow a mass production in economic series, by molding. Finally, from a certain diameter of rotor 1, allowing the multiplication of rotor poles (with corresponding multiplication of the number of lamellae of the switch) and stator poles, the yield obtained becomes particularly advantageous.

In FIG. 7, where the same references designate the elements corresponding to those previously described, another embodiment is shown, designed exactly according to the same principles but having a rotor 1 divided into three elementary rotors 73, 74 and -75 Each rotor elementary comprises two regions with notches, respectively 76, -77 and 78, which receive electrical conductors, and two diametrically opposite regions, devoid of notches and form "North" poles and
South ", with an alternate arrangement of these blades in the axial direction, as shown in the drawing. The length of the central elementary rotor 74 is equal to twice the length of each of the extreme elementary rotors 73 and 75. In correspondence with the structure of the rotor 2) the stator 3 here comprises polar masses at "E s giving in the axial direction triple blades. Each stator pole mass is formed by an elongated sole 24, but the latter receives three blocks 79, 80 and 81 with polar expansions, the length of the: central block 80 being twice that of the end blocks 79 and 81.

 As is obvious, and as already follows from the above, the invention is not limited to the sole embodiments of this rotary electric machine which have been described above, by way of examples; it embraces it, on the contrary, all the variants designed on the same principle, in particular whatever the number of poles on the rotor and on the stator, and whatever the division of the rotor into two or more elementary rotors.

Claims (7)

- CLAIMS ~ 1.- Rotating electric machine with direct current or rectified alternating current, comprising a rotor (1), the blades of which, in even number, have non-variable polarities, alternately "North n and" South, and a stator (33 whose blades (I to VI), in greater number than those of the rotor (1), are magnetized by coils (29 to 34) all connected together and supplied by a switching device (35) formed, on the one hand , by a set of conductive strips (38,39) alternately positive and negative, in the same total number as the rotor poles, separated and electrically isolated from each other by neutral strips (41) and carried by the shaft (2) of the rotor (1), these conductive strips (38,39) being electrically connected to slip rings (36,37) also carried by the shaft (2) of the rotor (1), and on the other hand, by an assembly of brushes (44,45,46) cooperating with the aforementioned lamellae (38,39,41) and electrically connected to the connection points (54,55,56) between the coils (29 to 34) of the stator (3), preferably by means of resistors (51,52,53), the rotor (1) being of the wound type, with its magnetized coils supplied, like the conductive lamellae of the switching device (35), from slip rings (19,20) carried by the shaft (2), and preferably supplied themselves via a rheostat (23), characterized in that the rotor (1) is cylindrical and has at its periphery notches (13,14) distributed in groups corresponding to the number of poles of the rotor (1) and separated by regions (15,16) without notches, said notches ( 13,14) receiving the windings (17) of coils connected to the slip rings (19,20) carried by the shaft (2), and in that, at the stator (3), diodes (61 to 66) mounted in Graetz bridge are inserted, bypassing the switching device (35), between the DC or rectified power supply or output terminals of the machine, and the connection points. on (54,55,56) between the coils (29 to 34) of the stator (3). 2.- rotary electric machine according to claim î, characterized in that its rotor (1) is formed of two or more elementary cylindrical rotors (10,11; 73,74,75) wedged on the same shaft (2), e , t magnetically isolated from each other, each p81e "North of an elementary rotor being situated opposite a pole t 'South" of the neighboring elementary rotor, and vice versa, and in that the arrangement of the polar masses of the stator (3) corresponds, in axial direction, to the division of the rotor (1) into two or more elementary rotors.  3. - rotary electric machine according to claim 2, characterized in that its rotor (1) is formed of two elementary rotors (10,11) identical in dimensions, but of alternating polarities, while the stator (3) comprises masses polar (24,25,26) in "U" giving, in axial direction, double blades. 4.- rotary electrical machine according to claim 2, characterized in that its rotor (~ i) is formed of three elementary rotors (73,74,75), while the stator (3) comprises' polar masses (24, 79, 80, 81) at "E" giving, in the axial direction, triple blades.  5.- ~ Rotating electric machine according to claim 4, characterized in that the central elementary rotor (74) has a length twice that of each of the two extreme elementary rotors (73.75).  6. A rotary electrical machine according to any one of claims 1 to 5, characterized in that, in the case of a bipolar rotor (1), the two regions (15, 16) without notches each occupy an angle of around 200, while the two groups of notches (13,14) each extend over an angle (o () of about 1,600.  7b rotary electrical machine according to any one of claims 1 to 6, characterized in that the polar masses of the stator (3) are not magnetically connected to each other, in the direction of the periphery of the stator, but are separated from one another others, and individually fixed, for example by bolting, inside an insulating carcass (4), in particular of molded hard plastic.  8. ~ rotary electric tachine according to claim 7, characterized in that each stator pole mass comprises an elongated sole (24), extending in the direction of the shaft (2), on which are mounted blocks (25, 26; 79,80,81) with pole shoes located opposite the elementary rotors (10,11; 73,74,75), the constituent parts of the pole masses being made in particular of molded ferrite. 9.- rotary electric machine according to any one of claims 1 to 8, characterized in that the ohmic value of each resistor (51,52,53), connecting a connection point (54,55,56) between the coils (29 to 34) of the stator (3) and a brush (44,45,46) of the switching device (35), is double due to the internal resistance of the diodes (61 to 66) mounted in Graetz bridge.  10.- rotary electric machine according to any one of claims 1 to 9, characterized in that each brush (44,45,46) of the switching device (35) feeds in parallel the stator coils (29 to 34) mounted on diametrically opposite polar masses, but in a "crossed" circuit so that the polarity of two diametrically opposite polar masses is North "for one and" South "for the other, and in that the poles (I to VI) are divided into two groups in the same number, which alternate with each other, two diametrically opposite blades (I, IV; II, V;; III, VI) always belonging to two distinct groups, and in each group the connection point (54,55,56) of a stator coil input (29 to 34), with the conductor connecting this coil to a brush (44545,46) of the switching device (35), coinciding with the exit point of the previous stator coil, so that the coils (29 to 34) form a crown.  11. Rotating electric machine according to any one of claims 1 to 9, characterized in that each brush (44,45,46) of the switching device (35) supplies in parallel the stator coils (29 to 34) mounted on diametrically opposite polar masses, but in a "crossed" circuit so that the polarity of two diametrically opposed polar masses is "North" for one and "South i for the other, and in that two coils in parallel mounted on diametrically opposite polar masses, the inputs of which are combined at the same connection point (54,55,56) connected to a brush (44,45,46) of the switching device (35) and to the diodes (61 66) mounted on the Graetz bridge, their outputs connected to a common circular conductor (60).  12. A rotary electrical machine according to claim 3 or 4 and claim 10 or 11, characterized in that each diode (61 to 66) of the Graetz bridge is rectifier with a current double the intensity admitted in two stator coils (29 to 34) connected in series with a Ctatoric polar mass at "E" or "U", the reverse voltage of each diade (61 to 66) being preferably at least about five times greater than the maximum voltage allowed at the terminals of the machine.  13. ~ Rotating electric machine according to any of claims 1 to 12, characterized in that it comprises, on its DC or rectified power supply circuit, an inverter switch with first contacts associated with a capacitor (72) and capable of reversing the direction of supply of the windings (17) of the rotor (1), and with other contacts capable of interrupting the supply of the coils (29 to 34) of the stator (3), during the reversal effected by means of the first two contacts, but without reversing the polarities of the stator (3).