FR2612704A1 - Asynchronous motor for variable speed with double stator and rotor with grids - Google Patents

Abstract

This motor is composed of 3 magnetic circuits 1, 3 and 9, consisting of spirally wound laminated armatures in the form of hollow cylinders of identical diameters, whose axes of revolution 11 coincide with the axis of rotation and are separated by two air-gaps located in planes perpendicular to this axis. With these magnetic circuits there correspond, in order: 1 fixed stator 1 provided with a polyphase winding arranged in radial notches 2 and connected to an energy source, 1 rotor 3 provided with 5 sets of radial bars 4 to 8 connected together to form 3 short-circuited electrical circuits, 1 stator 9 pivoting about the axis of rotation and provided with a polyphase winding arranged in radial notches 10 and connected to the same energy source. The various positions of this stator determine different speeds of rotation.

Description

CRIPTI ION
The equipment and installations which use movable members are likely to use, for their implementation, variable speed drive devices, in order to meet the requirements of the various operating regimes.

The most practical solutions to this problem call on electric motors, namely: a) direct current motors b) asynchronous motors driving variators and mechanical gearboxes c) asynchronous motors with wound rotor with rings and adjustment rheostats d) synchronous and asynchronous motors supplied at variable frequencies by DC and AC converter devices e) asynchronous motors with collectors
These solutions, which are very widely used, however have certain drawbacks arising either from their complexity, from their fragility, from their lack of energy saving, from their high cost.

 The asynchronous motor with double stator and with rotor with grids, called "motor with grids", object of the present invention, proposes a solution to this problem, by bringing adventures in the fields of simplicity, robustness and economy.

 It has 3 elements, namely: the fixed stator, the rotor, 1 pivoting stator ensuring the adjustment of the speed of rotation.

 The active parts of these 3 organs are constituted by magnetic circuits of cylindrical shape, of the same diameters and whose axes of revolution coincide with the axis of rotation of the motor. These 3 elements are separated by 2 plane air gaps delimited by the bases of the cylinders and located in planes perpendicular to the axis.

These magnetic circuits are produced by means of sheets wound in a spiral, constituting laminated armatures.

They are cut to form radial notches, i.e. located in planes perpendicular to the axis of rotation. With regard to the two stators, these notches are arranged on their internal faces. They each receive a connected winding to a source of energy and arranged for a rotating field, the direction of rotation of these two fields being the same, The lines of flux cross the air gaps following the direction of the generatrices of the cylinders, that is to say perpendicular to the plane of These airfoils are laminated to cylindrical carcasses. With regard to the rotor, 2 groups of radial notches are arranged on the 2 bases thereof, facing the stators, 2 groups of radial notches are arranged. on either side of the median plane and 1 group of notches is placed in this median plane.

The notches of the first 4 groups receive 4 busbars connected together to form 2 polyphase circuits in parallel, short-circuited. The group of radial notches arranged in the median plane receives 1 busbar shorted at its 2 ends. All of these busbars are called "grills", hence the designation "grid motor". The purpose of this device is to vary the intensity of the magnetic flux resulting in the rotor circuits as a function of the position of the pivoting stator. This variation in the resulting flux causes the variation of the rotation speed of the motor, according to the theory of asynchronous motors. At low speed, the 2 stators must be positioned so as to have identical polarities. The main flux lines then cross the rotor in axial directions, closing in the external parts of the stators, thus forming only '' a single magnetic circuit traversing the 3 armatures. In this case, the composition of the magnetic fluxes in the rotor leads to a minimum resulting flux, therefore at a minimum speed (maximum slip). in synchronism speed, the 2 stators must be positioned so as to have opposite polarities.

The main flux lines close inside each of the 2 halves of the rotor in circular paths, and they are closed in the same way in the
external parts of the stators, thus forming 2 separate and opposite magnetic circuits. In this case, the composition of
magnetic fluxes in the rotor leads to a maximum resulting flux, therefore to a maximum speed (minimum slip).

The offset between these 2 positions is slightly greater than an angle equal to that of the pole step (i.e. p being the number of pairs of poles). The intermediate positions leading to intermediate speeds.

The production of this motor uses conventional means used in the construction of electric motors with regard to the carcass, the shaft and the various mechanical parts. On the other hand, the manufacture of the 3 laminated armatures requires a particular embodiment.
The spiral winding of the magnetic sheets involves the implementation of a continuous automatic cutting line using materials in use in this field.
(cutting presses or punching machines) .The automatic sheet metal advance device requires special equipment (mechanical or electronic) which ensures the exact positioning of the radial notches and other cut parts taking into account the variable diameter of the part wound and the distance which separates these notches from the cutting tool. On the other hand, the sheet metal strip must be subjected to a sufficiently high tensile force so that it rolls up, at the end of the line, with all the desired rigidity and minimum expansion. This high tension, which should not affect the relatively weak torques which drive the unwinder and the retractor, is exerted on them by a differential type system with planetary gears and satellites , which each subjects them to an equal and opposite torque, while allowing easy movement of the strip. The torque applied to the differential is exerted via a mechanically or hydraulically operated transmission system.

 FIG. 1 schematically represents, in a side view, the 3 laminated armatures constituting the 3 organs of the engine, namely, and in order from left to right: the fixed stator, the rotor, the pivoting stator.

 Figure 2 shows, in longitudinal section, a practical embodiment of the engine.

 Figure 3 shows in detail the fixed stator in a longitudinal half-section.

 Figure 4 shows the same way, the rotor.

 Figure 5 shows in the same form, the pivoting stator.

 Figure 6 relates to the 3 bodies of Figures 3, 4 and 5, assembled in a longitudinal half-section.

 FIG. 7 represents a transverse half-section with, in the left part, the fixed stator along the axis A and in the right part, the rotor along the axis BB.

 FIG. 8 represents a diagram of connections of the five busbars of the rotor.

 FIG. 9 represents, in exploded schematic side view, a simplified variant of the rotor in which the two groups of notches and the corresponding bars which are on either side of the middle part, according to the invention, are merged into a only group located in this median plane.

 FIG. 10 represents, in a view from the outside, the device for fixing the rotor to the shaft.

 FIG. 11 relates to the method of shaping the laminated reinforcements and represents the diagram of the tensioning device applied to the unwinder and to the reel of the automatic cutting line.

All of the previous figures correspond to a project for the realization of a variable speed "grill motor", the characteristics of which are as follows:
Maximum power: 72 kW
No-load speed: 1000 t, 'min. (6 poles)
Power supply: three-phase 220i350 V. 50 Hertz
The device shown diagrammatically in FIG. 1 comprises 3 cylindrical laminated armatures of the same diameters constituting the 3 organs of the motor, namely: 1 fixed stator (1) with 1 set of radile notches (2) 1 rotor (3) with 5 sets radial notches (4) to (8) 1 pivoting stator (9) with 1 set of radial notches (10) 1 axis of revolution of the cylinders (11) coincident with the axis of rotation of the motor.

 These bodies are shown in detail in Figures 2 and 3, where we find: the fixed stator (1) whose outer diameter is 540mm and the inner diameter: 220 mm the length of the generators is 100 mm.

 This stator is provided with 36 radial notches (2) receiving a three-phase hexapolar winding with consequent poles with 2 notches per pole and per phase, i.e. 36 notches with 4 straight coils, the mixed coil, 4 angled coils. ) are arranged in the interior and exterior parts of the cylindrical frames.

The laminated frame (1) is wound on a sleeve (13j, mounted on a flange (14). The outer peripheral part of the frame (1) comprises series of cavities with notched notches (15) in which s 'recess fixing devices (16) connected to the flange (14)
Separated from the stator (1) by an air gap, there is, detailed in FIG. 4, the rotor (3) of the same diameters at the air gap, namely 540 mm (D.ext.) And 220 mm (D.int .) the length of the generators being 210 mm. This rotor (3) is provided with 5 sets of 26 radial notches offset by a tooth pitch between the base and the top. The 2 sets of enco (4) and 8) each receive 1 set of bars constituting the so-called main grids. The 2 sets of notches (5) and (72 each receive 1 set of bars constituting the so-called secondary grids. The set of notches (6) in the median plane receives 1 set of bars constituting the so-called compensation grid. This grid is short-circuited by 2 rings (17) and (18d fixed by welding) The secondary grids (5) and (7! Are short-circuited by 2 rings (19) and! 20! Assembled by welding to the inner part, they are connected to each other, to the outer part, by bars (21) inclined by 7 geometrical in the opposite direction rotation (figure 8 - angle b)
The main grids (4) and (8) are short-circuited by 2 rings (22) and (23) welded to the inner part. The grate (4) is connected to the grate (5) to the outer part by a bar. (24) inclined by 7 geometrical in the direction of rotation (figure 8 - angle a)
The grid (8) is connected to the grid (7), to the external part, by a bar (25) inclined with a dental pitch, that is to say geometrical, in the opposite direction to the direction of rotation (FIG. 8 - angle vs)
The laminated frame present in the interior of crenellated projections (26) which are embedded in the fixing and clamping devices (27) themselves assembled to a sleeve (28) integral with the shaft (29).

Separated from the rotor by an air gap, is detailed in FIG. 5, ie the pivoting stator (9) of the same diameters at the air gap. The length of the generators is 100 mm. This stator is provided with the same number of radial notches ('Q) and of the same winding as the fixed stator (1) with the same coil heads (30)
The laminated frame 9) is wound on a sleeve! 31) mounted on a pivoting flange (32) around the axis of rotation by means of the tangent screw device (33). The outer peripheral part has the frame (9) comprises series of cavities with crenellated notches (34) in which are embedded fixing devices (35) connected to the pivoting flange (32. ;;
This flange performs its rotational movement around a pin secured to a fixed flange r36) by means of the tangent screw device (33) mentioned above. The 2 flanges 14; and (36) are assembled to a carcass (37i FIles support the bearings (38j and (391 as well as the motor shaft (29j
The process for manufacturing the laminated armatures constituting the axial magnetic circuits is shown diagrammatically in FIG. 11 It represents the automatic cutting line with its cutting press (44), the strip unwinder (45) and the reel (46). The tension necessary for the rigidity required for a good winding of the sheet metal strip is ensured thanks to the use of the differential system (47) whose satellites are subjected to a force transmitted to the crown to which they are secured by a rack bar The step-by-step drive of the sheet metal strip is provided by the reel actuation device (49) and transmitted to the unwinder (45) by means of the differential (47), the strip of sheet remaining subjected to the voltage which is communicated to it by the satellites. The command and control of the course are governed by a device (49) which may be of an electrical, electronic or mechanical nature.

 The device according to the invention is intended to ensure the training of materials and installations, the implementation of which requires operation at variable speed. It can also directly control equipment whose speed variation is actuated manually, that '' be integrated into a set of installations fitted with remote-controlled automatic speed regulation devices via servo motors.

Claims (6)

R E V E N D I C A T I O N S  1) Device for varying the rotation speed of an asynchronous motor comprising 3 elements, namely, in order: 'fixed stator (1), 1 rotor (3), 1 pivoting stator  9; whose operation determines the speed variation,  the stators receiving polyphase or single-phase windings and the rotor receiving short-circuit busbars, characterized in that the magnetic circuits of these 3 elements have the form of cylinders of revolution, hollow, with the same internal and external diameters, including the axes of revolution are merged with the axis of rotation of the engine (, in that these 3 cylinders are separated by 2 plane air gaps delimited by the bases of the cylinders and situated in planes perpendicular to the axis, in that the 2 stators ( 1) and 9) receive electrical circuits forming polyphase or single-phase windings connected to an energy source and whose bundles are arranged in radial notches (2) and (10) arranged on the internal faces of the air gap side, and in that the rotor (3) receives, in radial notches, 5 busbars, called grids, namely: 2 main grids (4) and (8), 2 secondary grids s5) and (7), 1 grating of compensation (6d.  2) Device according to claim 1, concerning the constitution of magnetic circuits of cylindrical shape, of identical diameters, separated by plane air gaps parallel to the bases of the cylinders, characterized in that the 2 stators (1) and r9) and the rotor ( 3) are each constituted by the internal volume comprised between 2 cylinders of revolution whose directresses are concentric circles and whose common axis is coincident with the axis of rotation of the engine (11), in that they are produced at by means of magnetic sheets wound in a spiral around the axis of revolution, thus forming laminated armatures intended to constitute an axial magnetic circuit for a rotating field, provisions generally applicable to the elements used in the construction of the different types of motors and electrical equipment using rotating fields.  3) Device according to claims 1 and 2 according to which 2 of the 3 constituent parts of the engine play the role of stators, characterized in that the magnetic sheets forming the laminated armature of each of the 2 stators Cl) and (9) are cut out their inner face, air gap side, to form radial notches (2) and (i0! and the coil heads (12) and (30) being placed on the inner and outer peripheral surfaces of the magnetic circuits, in that these sheets are cut out on the external peripheral part to form a series of cavities with snow-created notches (15 ) and s4) intended to receive fastening devices 16) and (35), connected to the motor casings (14) and (32) and in that the strip of magnetic sheet is provided, at its o rigid, of a read cut notch allowing it to be hung on the sleeve (13)  4) Device according to claims 1, 2 and 3, in which the laminated armature constituting the fixed stator (1) has cut parts intended to receive fixing devices, characterized in that the internal part of the laminated armature of the fixed stator, v1) is mounted on a sleeve (13) which acts as a rusting mandrel by means of the notch with which it is provided. This sleeve is fixed to a flange (14) supporting in the central part a bearing (38) receiving the rotor shaft (29) and in that the peripheral part of this flange has shoulders receiving clamping parts (16) ensuring ia longztudinal and transverse fixing of the magnetic circuit by means of notches created linked (15) mentioned above (claim 35.  5j Device according to claims 1, 2 and 3, in which the laminated armature constituting the pivoting stator carries cut parts intended to receive fixing devices, characterized in that the part  internal of the laminated armature of the pivoting stator (9) is mounted on a sleeve (31) serving as a winding mandrel by means of the notch with which it is provided. This sleeve is fixed to a pivoting flange  (32), the axis of which coincides with the axis of rotation, in that the peripheral part of this flange has shoulders receiving clamping pieces r35) ensuring the fixing of the magnetic circuit by means of the notched notches ( 34) mentioned in claim 3 in that this frame pivots around a pin forming part of a fixed flange (36) supporting in the central part a bearing (39) receiving the motor shaft (29), in that that the rotation of the pivoting flange (32) is ensured by a tangent screw device (33) driven manually or by i '.ntermediate of a servo-motor, and in that this flange pivots by describing a route slightly greater than the angle corresponding to the pole pitch (that is to say n / p, p being the number of pairs of poles), in the direction of rotation of the rotating field, in order to obtain a variation in the speed of the motor , the starting point (speed close to synchronism) being that where the flow lines of s stators are directed in direction. on the contrary, the end point (slow speed) being that where the stator flux lines go in the same direction.  6 j Device according to claims 1 and 2 in which the third component of the engine plays the role of rotor, characterized in that the magnetic sheets forming the laminated armature of the rotor (3) are cut on the 2 external faces, as well as '' in 3 places located in the central part to form 5 series of radial notches (4. 5, 6, 7 and 8) intended to review conductive bars and e that the sheets are cut in the internal part to form protrusions crenellations (26) intended to receive fastening and clamping devices (272.  7) Device according to claims 1, 2 and 6, wherein the laminated armature constituting the rotor has 5 series of radial notches, characterized in that the rotor receives 5 busbars, called grids, and placed in the 5 series of notches E4, 5, 6 7 and 8), arranged in the rotor, in that this assembly comprises: 2 main grids (4) and (8), each placed in the vicinity of the 2 air gaps, 2 secondary grids (3) and (7), placed on either side of the median plane, 1 compensation grid (6) placed in the median plane, in that the bars constituting the compensation grid (6) are short-circuited by the '' intermediate 2 conductive rings (17) and (18) placed against the internal and external parts of the rotor and made integral with the bars by welding, in that the bars constituting the 2 main grids (4) and (8) and the 2 secondary grids (3) and (7) are short-circuited by means of 4 conducting rings (19), (20), (22), (23), placed against the internal part of the rotor and made integral with the bars by welding, in that the bars are connected together in the external part of the rotor by welded connections (21j, (24) and ( 25) forming with the generatrices of the cylinder constituting the rotor, 3 angies defined on the connection diagram (FIG. 4), namely: the angle â which is positive and can vary from 10 to 30 electrical depending on the characteristics of the magnetic circuit and the values of the tooth pitch adopted (1 electrical degree 1 geometric degree x number of pairs of poles) (the positive direction is that of the direction of rotation), the angle b which is negative and can vary from 10 to 30O electrical in the same conditions that the angle at angle c which is negative and can vary from 10 to 600 electrical under the same conditions as above and in that in a simplified version (Figure 5!, the 2 secondary grids (5) and (7 ) are merged into a single grid (5-7), located in the median plane, as shown tiling of the compensation grid (6).  8) Device according to claims 1, 2 and 6 in which the laminated frame constituting the rotor has projections intended to receive fixing devices, characterized in that the internal part of the laminated frame forming the magnetic circuit of the rotor is mounted on fastening and clamping devices (27) which have locations (40) for enclosing the crenellated projections (26) and for holding the crowns of the grids (41), in that these locations (40) are arranged in directions alternated so that the rotor is held in the normal direction of rotation and in the opposite direction, in that the fixing devices are supported by a sleeve (28), made integral with the shaft, the contact surfaces having a slight taper and tightening being done by means of bolted threaded rods (42), and in that the sleeve has clearances (43) allowing the mounting of the fixing devices by rotation then by longitudinal traction.  9) Method for the production of laminated armatures forming axial magnetic circuits according to claims 1, 2, 3 and 6 using a continuous automatic cutting line receiving a coil of magnetic sheet metal placed at the head of the line on the reel (45 ) characterized in that this sheet after passing under the cutting press (44) is assembled directly and definitively on the reel (46) at the end of the line, the sheet strip being subjected to a high tension originating from the action d '' a rack bar (48) subjected to an axial force which it transmits to a toothed ring integral with the satellites of the differential system (47), which transform it, by means of the 2 planets of the same differential and 2 pinions of angle gear, in 2 pairs of opposite directions applied to the unwinder (45) and the retractor (469