BE501811A - - Google Patents

Description

       

  ROTATING FIELD MACHINE.

  
In the early days of the development of three-phase asynchronous motors, these were made with salient poles and concentric excitation windings. The rotor most often had a two-phase winding in short circuit. Such engines, unquestionably, worked,

  
but their output was absolutely uneconomical. It is only when

  
we began to use the distributed windings and cage rotors that

  
motors were obtained which could be used economically. Over there

  
As a result, efforts have always been made to replace distributed windings, which are particularly difficult to manufacture, especially with regard to small motors, by concentric windings, machine wound, but all these attempts have failed. This, in particular, is also true for

  
motors with disc-shaped rotor, and separate pole expansions

  
from each other by curved gaps, oblique with respect to the radius.

  
These engines were constructed in such an unfavorable manner that from the point of view of their difficult manufacture they would never have been susceptible of industrial realization, and moreover they were unusable, for physical reasons, so that for tens . of years all three-phase asynchronous motors are built as in the past with distributed windings, and in cases where this results in difficulties, as for example for motors of less than 150 watts, we go to: motor with collector.

  
In practice, motors with salient poles and concentric windings are only found in meters and other measuring devices, as well as in record players and similar devices. which work in a manner analogous to that of the measuring system of a meter, and for which the question of efficiency is of only secondary importance. These motors most often have a smooth copper or aluminum disc. Their efficiency is very low, so that at first glance they are not suitable for notable powers. Also included in the same group are split-pole motors of the "Splitphase" or "Spaltpolmotoren" type, some of the poles of which are omitted. But these motors also have a very poor performance, and moreover have the disadvantage of

  
 <EMI ID = 1.1>

  
Three-phase asynchronous motors, even when little consideration is given to efficiency, should only be constructed with distributed winding.

  
 <EMI ID = 2.1>

  
te of new research, to this result by the simultaneous use of determined means, known in themselves. It is possible to establish, in particular in the field of low powers, rotating field machines with salient poles and concentric windings. According to the invention, such a rotating field machine comprises per phase, two or a multiple of two salient poles with concentric windings, wound in opposite directions, -the minimum number of poles for three-phase current, is therefore six- and, in the case of a motor with a short-circuited rotor, it further comprises a cage armature having a relatively low resistance. The poles or the notches of the rotor are preferably arranged at an angle.

   The cage considerably reduces the unfavorable action of the upper harmonics, which do not contribute to generating the motor torque, and which make the rapid rotation of the motor difficult. This action is reinforced by the oblique arrangement of the poles or the notches of the rotor. For this purpose, the polar overlap of the armature is determined, preferably empirically so as to obtain the optimum characteristics. Tests have shown that still acceptable service conditions can be achieved even with low polar recovery factors. Consequently, one can optionally employ polar expansions which do not laterally extend beyond the polar columns. This allows pre-prepared windings to be mounted on a one-piece stator without having to create joint surfaces.

  
Furthermore, according to the invention, the poles of the various phases or of the auxiliary phases can be composed of two or more partial poles with concentric windings. We keep in this way all

  
the well-known advantages of salient poles and concentric windings, while obtaining, as regards the connection of the different poles, greater independence.

  
According to the invention, it is also possible to obtain an action similar to that of the winding distributed with respect to the rotating field by equipping at least part of the partial poles with partial windings, which are connected to different phases, in a manner to obtain an action similar to that of a distributed winding. Instead, the partial poles of the different phases can also be inverted in space, at least partially, so as to obtain a similar effect. The additional copper required by the concentric poles for the subdi-

  
 <EMI ID = 3.1>

  
The length of the motor is shorter, because the usual three-phase motors have much larger coil heads than those of machines constructed according to the invention. As the concentrated windings are much easier to manufacture than the distributed windings, the object of the invention is of economic interest all the more appreciable as the number of turns of the winding is greater. it results in particular that the low-power motors constructed according to the invention are much more advantageous than the three-phase current motors of current construction.

   As the concentric windings can be isolated more easily and for higher voltages than the distributed windings, the insulation of which, in the event of installation, or the like, can moreover easily be damaged; The object of the invention is also advantageous for motors whose insulation is highly stressed and for motors with higher voltage. The concentric windings also provide better mechanical resistance to short circuits,

  
and do not require special reinforcements.

  
If the winding, from the point of view of the constitution of the rotating field, has an action similar to that of a distributed winding, we are in no way limited to a cage rotor, but we can without any hesitation also use other types of rotors or armatures, for example slip ring armatures.

  
On the other hand, according to the invention, it is possible to place a ring of solenoids between two disc rotors provided with cage windings. From the magnetic point of view, the different parts of the machine are preferably coupled in such a way that the magnetic flux closes each time by a first solenoid, one of the rotor discs, a second solenoid and the other rotoro disc Of course, one can instead of a solenoid use a group of solenoids "The disc-rotors can be made of the

  
 <EMI ID = 4.1>

  
notches are stamped before or during rewinding, or milled after rewinding. The cage is then introduced, cast, injected by any method, in a known manner. Along with the cage, the fan blades can be fabricated, as well as the hubs or other disc-rotor retainers.

  
According to the invention, the pole columns of the salient poles can be arranged in groups, parallel or in a substantially parallel manner. The advantage here is that coils made up

  
can easily be threaded on the pole columns beforehand. The location for the windings can also be better utilized. In addition, this advantage is obtained that such a machine can be constructed so that its size is less along certain main axes than that of machines with a round stator and. with polar columns arranged radially. This arrangement is particularly advantageous for machines intended for operation in two fluids, since the rotor space, as will be described later, can easily be separated from the space of the windings by a capsule, so that, l 'one can for example have the rotor coupled to a pump within the fluid to be circulated, which eliminates the "stuffing boxes", which are most often undesirable.

  
In order to be able to easily introduce the concentric windings, despite the presence of the polar expansions, it is necessary to provide for the removability, either of the whole pole, or of the polar expansion, as is done for direct current or synchronous machines; this results in magnetic seals, through which all of the polar flux must pass. To decrease

  
the reluctance of these joints, they must be as narrow as possible, but since the different pole pieces - which are crossed by an alternating flow - must be laminated, short circuits can easily occur between the different lamellae, which causes the poles to heat up at the joints, hinders the flow of flow and increases the losses of the machine. This is undoubtedly a disadvantage for the mass production of such motors, since the degree of the magnetic short circuit varies from motor to motor, and therefore motors have different characteristics. If, on the contrary, one makes poles from one piece, including the yoke and the polar expansion,

  
the advantages of concentric windings, i.e. ease of machine fabrication, excellent insulation, good use of the space available for the windings, etc., are lost, since the winding must be wound on the machine itself or be fed into it in another way.

  
The advantages of concentric windings can be retained, while avoiding the disadvantages mentioned above with regard to

  
magnetic seals, when the gap between the poles, the width of which must be equal to or less than the internal dimensions of the concentric windings, is filled with shims consisting, along the edges of the poles, of magnetic materials. There are still joints left, in this way, but these, instead of being crossed by the whole of the alternating flow, are only crossed by a small part of it.

  
Forms of construction similar or identical to those of the magnetic wedges used for closing the slots of three-phase motors with distributed windings can be used for these wedges, such as, for example, the spacers consisting of two bundles of joined sheet metal. by brass bridges.

  
When we want to manufacture the windings completely independently, or when we want to wind them directly on the poles, without renouncing the enlarged pole expansions, we can also assemble the poles by constituting magnetic joints and we can still reduce the number of ampere-turns necessary for these seals if they are extended

  
at least up to the cylinder head of the machine, in order to increase the surface

  
magnetic seals. For this purpose, the poles can be made to penetrate into the yoke, for example by giving the poles a dovetail shape. The poles assembled with mortise and tenon can be split, so as to form a spring. It is particularly indicated to widen the poles in the form

  
of T, at the place of the gasket with the cylinder head. These enlargements in the form of

  
T can then constitute sectors of the cylinder head itself. To further increase the surface area of the joints, the poles can also be given a serrated shape at the location of the joints.

  
The pole pieces and the cylinder head parts can be held together, for example, by reinforced end plates or

  
by welding, by a casing with shims, by clamping rings, ties or the like. They can also be maintained in addition by wedges placed between the pole expansions, by brackets surrounding the yoke or any other device.

  
To facilitate the manufacture of small motors for three-phase current, they can be made in a Scott assembly, with 4 salient poles.

  
Three-phase asynchronous motors intended for networks with 50 periods / s have no-load speeds of 3000, 1500, 750, etc ... revolutions / minute.

  
As a result of the slip, the actual operating speeds are somewhat lower. The speed stages are therefore very coarse. The intermediate speeds between these stages can only be obtained by a considerable increase in the slip, or by a modification of the frequency, or even by certain modes of cascade coupling. All these means are however relatively inconvenient and expensive. It is especially uneconomical to run these motors for a long time with a large slip.

  
The abandonment of distributed windings allows to create machines

  
with rotating field thanks to which it is possible to obtain without modification of the frequency, without mechanical modification of the poles and without abnormally high slip, speeds of rotation which, without this, could only be obtained by using the means described above

  
According to the invention, the poles of the machine can be

  
 <EMI ID = 5.1>

  
te a series, either of unwound poles, or of non-excited intervals, The pole pitches of the different phases can also be different. Thanks to this unequal distribution of the blades, it is already possible to obtain synchronous speeds, when idling, which are abnormal, and which, with relatively small slip values, and which are still economical, give abnormal operating speeds. These service speeds are subject,

  
in the event of load variations, much smaller fluctuations than those which would occur, for example for a slip ring motor of a known type, which would be adjusted at an abnormal speed causing an abnormally high slip. This is an advantage for different use cases. Although the unequal distribution of the poles causes, in particular because of the higher harmonics that it causes, a certain reduction in efficiency, this is not as great as that experienced by a conventional rotating field motor for which the abnormal speed is obtained thanks to a significant slip. An appreciable advantage also consists in the fact that for the abnormal speeds of rotation,

  
a low resistance short-circuited rotor can always be used, thus sparing the costly windings connected to the slip rings. A reduced resistance of the cage winding even constitutes, for the invention

  
 <EMI ID = 6.1>

  
mortis.

  
While the wavelength of the rotating field, for three-phase asynchronous machines known until now, is a sub-

  
 <EMI ID = 7.1>

  
machine is an integer multiple of the wavelength of the rotating field, and the rest also in the event of a change in the coupling of the poles, it is possible, by dispensing with the distributed windings, to couple the poles in such a way that the wavelength of the rotating field born be plus an exact submultiple of the peripheral length. Of course, it is possible to use couplings for which the perimeter is an integer multiple as intermediate stages.

  
of the wavelength of the rotating field.

  
Since the wavelength of the rotating field is not a submultiple of the length of the perimeter, there remains on the perimeter a "remainder". This one can remain non-excited, or its windings can be short-circuited, or else the "remainder" can be connected to part of the phases, so that there remains for this "remainder" only one part of the wavelength of the rotating field.

  
In order to obtain a greater diversity of rotational speeds in this way, the pole pitches of the different phases can be given different dimensions, as will be explained below, when examining the figures.

  
To avoid a magnetic imbalance, and to keep the non-excited intervals small, it is recommended to subdivide the "remainder" into two or more non-excited intervals, evenly distributed over the entire periphery.

  
The invention also has appreciable advantages for synchronous machines. In the early days of the construction of synchronous machines, it was proposed to constitute the alternating current part by assembling several bundles of sheets, in the shape of a U, each comprising their winding, and to keep these various bundles of sheets tightly together. against each other by rings or the like. However, this proposal has not received the sanction of practice. For large synchronous generators, the alternating current part is carried out rather, generally using grooved annular sheets or sheets in the form of segments, stacked, the windings being placed in the known manner in the notches.

   For very large machines, in order to facilitate transport, the alternating current part, which is most often the stator, is often separated into two halves, which can be transported separately.The coils located at the magnetic joints of the two halves are removed for transport then put back in place, after arrival at 'destination * For the fa-

  
 <EMI ID = 8.1>

  
our large-scale tools. As a result, the manufacturing costs are significantly increased.

  
As high power synchronous machines are designed almost exclusively for high voltages, the alternating current windings must have exceptional insulation. Due to this considerable insulation, the filling coefficient of the slots decreases and there also remains the risk of damaging the insulation when placing the coils.

  
As high resistance to short circuits is increasingly demanded, the coil heads must be very carefully reinforced. Due to the large dimensions, temperature variations lead to

  
 <EMI ID = 9.1>

  
which can easily cause damage to the windings, and loosening or abnormal stress on the various parts.

  
Difficulties of this kind can be avoided for large synchronous machines, in particular for large slow speed synchronous generators of hydraulic power plants. According to the invention, unlike the construction employed heretofore, a construction consisting of pole supports, preferably composed of individual elements with salient poles and preferably with concentric windings, is also used for these machines. The various elements of the alternating current part can consist of sectors comprising several salient poles, for example six, each of these poles comprising a concentric winding. These sectors can be put together in a simple way like a building set.

   Since there are no windings at the location of the magnetic joints between sectors, these can be manufactured and transported separately, then assembled. The tedious operation of installing the magnetic seal coils is eliminated. Sectors can be machined on relatively small machine tools. As a result, their manufacture is simplified and made more economical. Windings can also be manufactured and insulated separately. They can be put in place without deformation on the different poles, unlike distributed windings, which must always be slightly deformed when entering the notches. The elimination of deformations practically avoids

  
 <EMI ID = 10.1>

  
rigidly. The coil heads, for concentric windings, are small, so that very high short-circuit resistances are obtained, sometimes even without reinforcement. The tiresome crossing of the coil heads is also eliminated. By using concerted windings, the reactance of the stator winding is increased. Thereby,

  
short-circuit currents are reduced and resistance to short-circuits is further increased. When the different parts are working, under the influence of variations in temperature, the expansions as a result of construction in different sectors, remain relatively small, and as each sector is individually wound, and there is no winding bridging the magnetic seals of the sectors, the windings cannot be damaged by the relative displacement of two neighboring sectors. Construction

  
from identical, individually machined components facilitates manufacture, transport, on-site assembly and replacement of damaged parts.

  
It is recommended in this case also to push the further. subdivision of the alternating current part into individual elements,

  
in such a way that each individual element has only two poles

  
with individual winding. Elements consisting of solenoids or the like, with magnetic cores arranged transversely to the

  
 <EMI ID = 11.1>

  
res directed radially inward. It is, however, advantageous in some cases to use prismatic magnetic cores with axially directed pole surfaces. In this way, it is possible to appreciably shorten the length of the magnetic lines of force in the alternating current part compared with that of the exciter part, and to reduce the losses in the iron. The packages of more or less prismatic sheets can be fixed by their middle or by their pole ends. In some cases, we can turn the alternating current parts, made using similar elements, and leave the poles excita-. motion still.

  
Obtaining a sinusoidal voltage, at least at no-load, can be ensured by giving an appropriate shape to the excitation curve as well as a particular shape to the polar expansions of the excitation poles. It is however possible, instead of this, or in addition, to couple in series, in whole or in groups, the windings of the alternating current electros, and distribute the excitation poles and the poles of the alternating current electros irregularly. relative to the others in such a way that the disturbing action of the concentric windings and of the salient poles on the sinusoidal form of the voltage is, at least approximately, compensated. This is perfectly possible, even under load.

  
A sinusoidal curve of the voltage, which meets the prescriptions of the REM as well as all the international prescriptions can always be obtained if one chooses for the stator any number of poles, which is multiple of the number of phases, but without be multiple of

  
 <EMI ID = 12.1>

  
not

  
phase for 750 revolutions / minute and 50 periods / sec a stator with
21 or 27 poles. (21 and 27 are multiples of number of phases, i.e. 3,

  
 <EMI ID = 13.1>

  
750

  
number of poles of the stator 24, because this figure, which is divisible by 3, is

  
 <EMI ID = 14.1>

  
for slow rotating machines, sinusoidal voltage curves absolutely as good as with the best distributed windings.

  
The invention is also advantageous for asynchronous machines for coupling networks. It is well known that it is possible to use, for inter-urban lines, very wide networks and other cases.

  
of this kind, - instead of transformers, reactance coils and motor-generators - asynchronous motors for coupling networks, part of which is connected to one of the networks, and the other to the other network, the

  
more often through transformers. The frequencies of the networks are to a large extent independent of each other. As a rule, the frequencies of the different parts of the network are only a few

  
or not at all different, so that the asynchronous motor stands still or turns slowly. The motor comprises a drive or braking device, which is controlled according to specific known guidelines.

  
As a result of their slow rotation and frequent stops, such asynchronous machines are very poorly cooled. As it is a question here, in the majority of the cases, of the transmission of very important powers, of
-such machines must be very large. There is therefore a need for their manufacture of large machine tools and specialized labor. We therefore find the same difficulties as in the construction of large generating machines.

  
According to the invention, such an asynchronous machine, or rotating differential transformer, can also be constructed using individual elements with salient poles and concentric windings.

  
To prevent the rotor from being immobilized in certain positions, and to obtain voltage curves as sinusoidal as possible, it is recommended to arrange the poles of the stator and the rotor in such a way that they do not overlap simultaneously in all the positions. . It is thus possible, for example, not using a series coupling of groups of poles or of all the poles of the same phase, to distribute the poles irregularly, so that the poles located at phase R overlap exactly in a certain position, that they are shifted for example by 5 [deg.] of the polar pitch with respect to each other at another place, that for the following position they are shifted by 10 [deg.] , and so on and determine

  
shifting in such a way that the higher order harmonics which result from the use of salient poles and concentric windings are exactly compensated. It is also possible to choose a different number of poles for the stator from that of the rotor, by employing an appropriate coupling of the windings.

  
The individual elements may in some cases be assembled only at the assembly site; in particular, in certain cases, it is possible to hold in place the individual elements of the fixed parts in non-metallic materials, such as cement, concrete, etc., by means of rails,

  
joists, etc.

  
As the coils must simply be slipped on the pole columns, or wound around them, we can also provide them with a rigid insulation, or even place the windings, or better the whole machine. in oil or other insulating liquid. This is considerably facilitated by the "transformer-like" construction of the machine. In any case, it is possible without difficulty to isolate the winding for very high voltages, so that in certain circumstances the transformers necessary for the lowering of the voltage can be omitted. To prevent, for very high voltages and when the windings are insulated by air, the production of corona, it is possible to provide a conductive coating on the insulating layer.

  
As the machine runs only at low speed, it can easily be built with a large diameter and with a large number of poles. It behaves like a large number of small transformers whose primary windings move slowly relative to the secondary windings. Due to the subdivision into many individual elements, a very large surface area is obtained for heat dissipation, and a large number of cooling channels. This ensures good cooling even when the machine is stopped. If the machine is placed in oil, all the working parts are vigorously sprayed with oil. In the "in-air" arrangement, cooling air can be blown between the individual elements, or cooling pipes can be passed between them.

   In some cases, the individual elements can also be welded to the pipes.

  
cooling.

  
If the individual elements are fixed in non-metallic materials, for example in the concrete foundations of the machine, the manufacture and transport of bulky cast or welded carcasses is spared. When the machine is placed in an oil tank, the walls thereof can be used for securing the individual elements.

  
 <EMI ID = 15.1>

  
different elements are easily interchangeable. In some cases, individual standardized elements can be used for the construction of machines differing either in power, diameter, number of poles, etc.

  
The appended figures describe the invention in more detail.

  
FIG. 1 represents a machine with a rotating field, with a cylindrical rotor.

  
Figures 2 and 3 show a similar machine, but with a disc-shaped rotor.

  
FIG. 4 represents a machine whose poles constituting each phase are subdivided into partial poles.

  
Figures 5 and 6 show partial pole couplings.

  
 <EMI ID = 16.1> and cylindrical rotor. Figures 8 to 10 show a machine whose excitation poles are arranged between two disc-shaped rotors.

  
Figures 11 to 19 show details of such a machine.

  
Figures 20 and 21 show machines especially suitable for operation in two fluids, with pole columns constituting parallel groups.

  
Figures 22 to 27 show means for creating the pole expansions of machines with salient poles and concentric windings.

  
Figures 28 to 37 show machines with recessed poles and large surface magnetic seals.

  
Figures 38 and 39 represent the diagram of machines in Scotto coupling

  
Figures 40 through 47 show similar machine construction forms.

  
Figures 48 and 49 show machines with irregularly distributed poles.

  
Figures 50 to 70 show the different coupling modes

  
machines whose poles constituting the phases are subdivided into partial poles.

  
Figures 71 to 81 show large synchronous generators, especially suitable for hydraulic units with low head.

  
Figures 82 and 83 represent a large asynchronous machine, suitable especially for coupling networks (differential transformer).

  
FIG. 1 schematically represents a motor with a rotating field with six salient poles 1 and concentric windings 2. The poles are coupled in such a way that those which are opposite belong to the same phase, but are of reverse polarity. If we designate the different phases <EMI ID = 17.1>

  
The distance a between the polar expansions is chosen so as to obtain the optimum effect.

  
The rotor 4 comprises a cage winding, with bars at an angle, with respect to the axis. The most favorable inclination for the bars depends on various factors, mainly on the order of the upper field harmonics which must be reduced as much as possible, on the number of bars on the rotor, on the number of poles and on the axial length. The number of rotor bars has no relation to the number of poles.

  
Figure 2 shows a motor with disc rotor 5 'and poles 6 having approximately the shape of sectors, following each other in the same order as for figure 1. This machine also has concentric windings, which can be found in 7 or in 8 or even at both locations (see figure 3).

  
These forms of construction present the following advantages despite the use of salient poles and concentric windings, a motor of economic use is obtained, which is, even in the field of small powers, absolutely equal to field motors usual turn. While conventional motors have a distributed winding which is all the more difficult to manufacture as the motor is small and its operating voltage is high, here we benefit from all the well-known advantages of concentric bearings, as well, for example, ease of machine manufacture, easy and inexpensive assembly, easy interchangeability in the event of damage, remarkable insulation, especially for high voltage machines.

   In addition, all the well-known advantages of salient pole machines are enjoyed, so, for example, complicated stampings are avoided, excellent sheet utilization is obtained, as well as a very clear construction, especially as regards the couplings of the various windings. If necessary, the space reserved for the windings or the poles can, without difficulty, be hermetically separated from the rotor space so as to prevent the passage of gases or liquids; or at least, this is much easier than in the case of machines with distributed winding. A particular advantage resides on the other hand in the fact that it is possible in this way to produce motors without collectors, even in the range below 150 w, with a relatively good efficiency.

  
FIG. 4 diagrammatically represents a motor with a rotating field, the stator 11 of which comprises a large number of salient poles 12 with concentric windings 13. Each group of 4 similar poles constitutes the pole of a phase. The groups of poles corresponding to the different phases

  
RST are arranged so that they follow each other again in order

  
+ R, - T, + S, - R, + T, - S. The rotor 14 has a cage winding 15,

  
at relatively low resistance, so that disturbing harmonics of high orders are reduced.

  
In Figure 5, some of the partial poles 12 have two windings 31, 32, which are connected to different phases. The figure schematically shows the winding mode of the motor. From left to right, we first have the partial windings of the first two partial poles, which are coupled respectively in the + R direction and in the - S direction. The 3rd and 4th partial pole, with undivided windings, are coupled in the

  
sense + R; the 5th and the 6th partial pole, which again have windings

  
 <EMI ID = 18.1>
- T; the two following partial poles are coupled according to - T, those which follow in the direction - T, + S, etc ........ In this way, we obtain a polyaxial, regular rotating field, similar to that which is obtained with a distributed winding. In FIG. 6, each partial pole has only one winding; for this reason, the partial poles of the different phases are partly inverted. Between the hatched partial poles, coupled in the + R direction, there are for example partial poles coupled in the - S and - T direction; this is how the partial pole following the first hatched pole is coupled in the direction - S, and the partial pole preceding the last hatched pole in the direction - T. After the last partial pole hatched, follow two poles coupled in the direction - T, and so on.

   Since the fluxes of the different partial poles always mix somewhat, in this case also an effect similar to that of a distributed winding is obtained. The effect of a finely distributed winding - without its drawbacks, that is to say the difficulty of manufacturing the insulation, etc. - is obtained all the better as the number of partial poles constituting the poles is high and the amount of poles coupled in the direction of a distributed winding is large.

  
The horseshoe shaped poles, as exemplified in Fig. 7, at 71 may also be used with a suitably disposed cage wound cylindrical rotor 63. The concentric windings and salient poles allow for a wide variety of embodiments, which cannot be achieved with distributed winding motors. Of course, other embodiments than those shown can be considered.

  
Such winding modes can be realized for motors as well as for generators, for three-phase motors and for two-phase or single-phase motors with auxiliary phase.

  
FIG. 8 represents the developed diagram of a three-phase asynchronous motor. A solenoid ring 101 with windings 102 and enlarged pole expansions 103 is disposed between two disc-shaped rotors 104 and 105, with cage winding. The magnetic field closes, as shown by curve 106, through the solenoids 101 and the two discs <EMI ID = 19.1>

  
Excellent smoothness of the iron, as there is no cylinder head strictly speaking, whereby such machines can be built relatively light and space-saving with little loss in the iron. On the other hand, the average lengths of the windings, which are preferably wound directly onto the cores of the solenoids, are as short as possible and anyway, much shorter than in the case of distributed windings, since the heads of the coils are very prominent. are deleted. this consequently results in an appreciable saving of copper, and by extension a reduction in losses in the copper. Because of the reduction in losses, the heating of the machine is also lower, the cooling devices can be simplified, and even be completely eliminated for small machines.

  
An easier to construct embodiment is shown in section by Figures 9 and 10. The solenoids 101 have cores of trapezoidal section, or at least are trapezoidal upright.

  
pole expansions 103. As also shown in Figure 11, they are a little wider in the middle at 107, to present sufficient seating for a fastening device, and the coil is subdivided into two halves 120 and 121. Gomme le show figures 9 and 10, the cores of the solenoids are clamped in their middle 107 between an inner ring
108 and an outer ring 109, or a clamping device with crowns with a conical interior 110, with the interposition of filling pieces 111 in the form of segments. The rings 109 and 110 serve at the same time for fixing the ring of solenoids to the casing 112. The inner ring 108 can also be made in the form of a star, comprising tabs 113 serving as spacers between two. neighboring solenoids.

   Special spacers, of course made of non-magnetic or insulating materials, can however also be provided.

  
In some cases, you can even remove the inner ring
108. The solenoids are then tightened against each other with the interposition of spacers and filling pieces, by the outer ring 109 or 110, like the elements of an arch, in the same way as the lamellae d 'a collector. Instead of the devices shown for fixing the solenoids, all the known methods used in the construction of the manifolds can be employed. The cores of the solenoids instead of being fixed by the medium 107 can also be fixed by the polar expansions 103, or by the polar expansions as well as by the medium, or else, in the embodiment shown in FIG. 12, -comportant a winding subdivided into three parts 120, 121 and 122-, they can be fixed in several places.

   It is also possible to bend the sheets of the cores of the solenoids in the form of an arc of a circle, so that the sides of the interior and exterior trapezoid with respect to the center, constitute arcs of a circle parallel to the periphery of the rotor. The different sheets of different width constituting the cores of the solenoids can be cut one after the other and then stacked using automatic machines, or even identical sheets can be stacked, then the package of sheets can be machined to give it the trapezoidal shape. . For machines with a higher number of poles, the trapezoids differ so little from the rectangle that identical sheets can be used.

  
The rotor shaft 114 is rotatably mounted without axial movement in the casing, for example, using known roller bearings, and the disc-shaped rotors can in some cases be adjustably wedged on the housing. shaft 114, using thick rings or the like so as to be able to correctly adjust the air gap during assembly.

  
As shown, by way of example, in figure 13, the solenoids
101, in the case of the version with external rotor, can be screwed onto
-an interior support piece 115, or else, as shown in figure <EMI ID = 20.1>

  
are in a movable casing 116, which simultaneously serves as a pulley, friction plate or gear wheel or which can be extended further

  
 <EMI ID = 21.1>

  
instead, it is also possible, as shown by way of example in FIG. 15, to bolt the solenoids 101 to the casing 112 from the inside. The outer shrink rings 109 may also, as shown in Figure 16, consist of wire ties, similar to those used to tie the rotor windings.

  
Of course, solenoids can still be attached in many other ways. Thus, for example, they can be coated, molded or injected into a solidifying mass, optionally, together with the casing or other support element. Although special devices are not essential for cooling, with regard to small machines (for the reasons mentioned above), for example, larger machines can be cooled as shown in figures 17 to 19. In figure 17 , there are fins 118 on the outer end faces of the discs 104, 105 constituting the rotor, or else

  
outside these discs these fins suck, through the orifices 119 located in the middle of the casing, the air which circulates between the solenoids
101, and which is rejected at the ends of the casing, through radial 125 or axial 126 openings, possibly with the aid of sheet metal blades 127 (see figure 17) Using only one fan 118 (see figure 18), we can suck in air from one end of the machine, at 128, and release this air, after it has cooled the solenoids 101, on the other side of the machine, at 126.. In FIG. 19, fins 130 are arranged on the inner side of the rotor disc 104, at 129 or on the inner side and on the shaft 114, or else, in general, between the two rotor discs;

   these fins suck in fresh air through orifices 131 of the flanges of the casing and reject it through the openings 119 of the casing, after having cooled the solenoids 101 Of course, we can, here also, provide only one single fan, and circulate the cooling air axially from one flange to the other. There are obviously many other possible arrangements for cooling, similar to those used for semi-closed machines, impervious to drops or splashing water, or for closed machines with internal cooling air currents and separate exterior. The fans can also be driven by special motors, as is the case with known machines with external refrigeration.

  
A motor with a cage rotor 207 (see figure 20) has 6 poles
201 to 206o The poles are excited by windings 208, in the direction R,
- T, S, - R, T, - S. The columns of the poles 201 to 203 are parallel and together with the yoke 209 constitute an electro with three branches. The poles 204 to 206 are arranged in the same way. The pole expansions 210 are distinct from the pole columns. The magnetic seals of each of the groups 201 to
203 and 204 to 206 are in the same plane, crossed by a wall 211 of a capsule 212 surrounding the rotor 207 and the polar expansions 210, which capsule can, for example, be filled with a liquid when used as a pump . The capsule is made of metal or an alloy having a sufficiently high electrical resistance so that the alternating flux which passes through it is not significantly reduced.

   It can also naturally be made of a dielectric material, for example, of plastic plates.

  
The yoke elements 209 are magnetically connected by a laminated yoke 213, the yoke of which is behind the plane of the figure, but this yoke can also, as shown in dotted lines at 230, be located in the plane of the poles 201 to 206, and form with these poles continuous lamellae or assembled in an appropriate manner.

  
As shown in Figure 20, the size of the motor is very small in direction h, much smaller than in the case of a machine with a round stator and pole columns arranged radially. Such a motor is therefore advantageous in cases for which there is little room available in the direction 11.

  
Figure 21 shows a similar embodiment, with
12 poles, arranged in 4 groups 214 to 217. The yokes 209 of the groups 214 and 215, as well as those of the groups 216 and 217 are magnetically connected by the parts 231, which are relatively much shorter, the calipers 213, 230 of figure 20. The remainder corresponds to figure 20. For engines which are not intended to operate in two different fluids

  
 <EMI ID = 22.1>

  
can be part of the polar columns. For small machines, the enlargement of the pole expansions can be dispensed with, so that the windings can be mounted without difficulty on the columns of the electroso For larger machines, it is possible to arrange between the poles, as is done in the notches of asynchronous motors, wedges whose sides are magnetic, and which serve to widen the polar expansions.

  
Figures 20 and 21 make it easy to verify that thanks to

  
 <EMI ID = 23.1>

  
bricked beforehand, can easily be mounted, and that the free space between neighboring poles of the same group can be used almost entirely for adapting the windings.

  
As indicated in dotted lines in FIG. 20, the polar crown can also be constituted by a heterogeneous ring 218, comprising the magnetically conductive parts constituting the polar expansions and the magnetically non-conductive parts constituting the polar intervals. This ring then constitutes the wall of the capsule, and the magnetic seal 211 is then disposed on its periphery.

  
A package of stator plates 301 (see Figure 22) of a three-phase asynchronous motor has salient poles 302, having grooves 303 in the vicinity of their end. In the gap between two neighboring poles is a spacer 304 shown. in two different projections in fig. 23. It consists of two packets of sheets 340 and 341, held by two brass plates 342, and fixed by screws, wires or bands passing through the holes 343 of the plates and plates.

  
of brass. Between the packs of sheets 340 and 341 there is a gap
344. Before placing the wedges 304, one can easily thread the set of windings 305 on the poles 302. These windings can be supported in seats 306.

  
 <EMI ID = 24.1>

  
naked. It is also possible, as shown in FIGS. 24 and 25, to hold the bundles of sheets 310, arranged along the edge by a rubber part 309, vulcanized to the sheets. To manufacture such a wedge, according to firm 25, one can use the waste resulting from the stamping of the notch 307 between the poles (see figure 24), and cut the holes 308 during the stamping of the sheets. stator. The waste is then stacked one on top of the other, and the channel formed by the holes 308 is filled with rubber. After vulcanization, the remaining sheets are then cut with a saw, along the dotted lines and finally the corner shown in Figure 25 is obtained.

   Such wedges are on the one hand very flexible so that they can easily be inserted and on the other hand are so strong that they remain perfectly in place during use.

  
As shown in Figure 26, the corners can also be made by assembling several parts, for example two sintered end pieces agglomerated 311, having the form of continuous bars, and a part 312 in the form of a wedge, which can also be made of wood, rubber or synthetic materials, which are introduced between the previous pieces.

  
It is also possible, as shown in FIG. 27, to produce the corners in one piece according to the agglomeration process, by constituting the end parts 313 using metal powders, and the intermediate part 314 using powders. non-magnetic, for example of powders of non-ferrous metals or ceramic agglomerates, and compressing and agglomerating the whole

  
In Figure 28, there is shown pole pieces 401, split 402 to form a spring, which are driven into the yoke 403 of

  
the machine. The concentric winding 404 is manufactured separately. It is threaded onto the pole piece 405, before it is put in place, then the pole piece 401 is pushed in, its ends tighten up passing through the neck 406, then move away again when the pole piece has arrived. at the bottom of its housing. In this way, the gap of the seal is narrow, and its reluctance low. The reluctance of the joint can be further reduced especially by greatly increasing its surface area.

  
In Figure 29, the pole pieces 401 have their end 407 wedge-shaped. In this case also, the windings can be wound in advance. After placing the pole pieces 401 in the cylinder head
403, the poles are fixed by inserting the wedges 408 'between the expansions for

  
 <EMI ID = 25.1>

  
carry, as already shown in Figure 28, a slot 402 forming a spring. They then fit into the narrowed part 406 of the cylinder head, when they are pushed into it like a press-stud. Figures 31 and 32 show two different views of an embodiment similar to that of Figure 29. In this case also the windings 404 can be manufactured in advance. The pole pieces 401 are fixed to the brackets 410 embracing the cylinder head, by means of a bolt 411 passing through the pole piece right through. In figure 33, the pole pieces 401 are attached to the yoke
403 by a dovetail assembly, and are keyed for example in 412 or in 413. In this case also, the windings can be prepared in advance.

   For assembly, the windings are threaded onto the pole pieces, and then the pole pieces with the windings are pushed axially into the yoke 403. In figure 34, the pole pieces 401 are enlarged in a T-shape at the location of the yoke. joint, so as to increase the surface thereof. The winding 404, in this case, is wound directly onto the pole pieces 401. The pole pieces 401 can be fixed by wedges 408, as in the case of figure 29. In the embodiments according to figures 35 to 37, the pole pieces 401 are further widened at the location of the seal, to such an extent that they already constitute adjacent sectors of the cylinder head. In this case also, the windings 404 are wound directly on the pole pieces constituting at the same time the yoke.

   The different parts can, as shown in Figure 36, be fixed using wedges 416 in a casing 417, and are held in this way by arching effect. The pole pieces 401 (see fig. 37) can also be serrated at the location of the joints, at 419, in order to increase the surface of the latter, and be held against each other by a ring of hooping 418, by ligature, or by the like.

  
In the Scott coupling, advantageous for small motors for three-phase connection, the windings 501 and 502 of a pair of poles (see figures 38 and 39) are traversed by the current of one phase R, while the pair of poles arranged perpendicular to the previous one receives a combined winding 503 to 506, connected to the other two phases S and T. The ampere-turns are to be determined according to the characteristics of the Scott assembly.

  
The big advantage of the 4-pole arrangement obtained in this way is that one arrives at extraordinarily simple geometric shapes, and that the maximum use is made of the space available for the windings which can be wound up. the machine. Figures 40

  
to 47 show different embodiments of a 4-pole motor of this kind, each of them being represented by two views. Figures 40 and

  
41 show an outer rotor 507 with cage winding 508, and a stator system 509 disposed inside, in the shape of a cross, comprising the windings 501 to 506. Figures 42 and 43 show an arrangement which is very similar to the usual shapes. ; the 4 poles are part of an external stator 510, and are provided with corresponding windings 501 to
506. It can be seen that, in this case, the space available for the windings cannot be fully used. Figures 44 and 45 show a rectangular shaped stator 510. This results in a much better use of the space available for the windings. However,

  
the stator windings 501 to 506 must have different diameters and thicknesses.

  
Figures 46 and 47 show a stator 510 of square shape. The locations for windings can be made absolutely identical. It suffices simply to shift the columns 511 of the pole pieces relative to the axes of the stator and to provide pole expansion 512 only on one side. The stator sheet packages can be arranged as is done for transformers.

  
The 4-pole arrangement has this additional advantage that it is possible with the same shapes and the same pole sections, to construct single-phase or two-phase motors.

  
Figures 48 and 49 schematically show the development of two embodiments with irregularly distributed poles.

  
The stator yoke is again designated by the reference numeral 601, and the rotor cage winding by 602.

  
 <EMI ID = 26.1>

  
The poles are reconnected in the + R, - T, + S direction,
- R, + T, - S. Then we meet a pole 630 without winding, then again a pole connected in the + R direction, and so on. The poles can have the same peripheral length, or different peripheral lengths. In the exemplary embodiment, the poles of phase S are narrower than those of the other phases. In the case of figure 48, the speed of rotation obtained is lower than if the location without winding,
630, was not foreseen, that is to say that if the poles were equally distributed on the periphery, since the rotating field, to travel the part of the stator which is covered with windings takes as long as it takes would put some around the stator, if there was no space free of windings.

   For the same periphery, the speed of movement

  
of the rotating field is therefore, for the embodiment according to the figure
48, smaller than if the poles were evenly distributed. The motor can have one or more intervals without winding or not excited. The irregular distribution of the poles leads, it is true, the production of higher harmonics which decrease the efficiency, but these harmonics are largely absorbed by the cage winding, and moreover the reduction

  
efficiency is not as great as that which would be suffered if we sought to obtain the same speed with equally distributed poles, thanks to a particularly high slip.

  
If one wishes to retain these advantages and obtain, with regard to the rotating field, an action substantially identical to that of a distributed winding, it is again possible, as shown by way of example in FIG.
49, subdivide the poles of the different phases into partial poles and provide

  
 <EMI ID = 27.1>

  
its, in such a way that there results an action analogous to that of a distributed rolling. Thus, the first two partial poles, which '. Are provided with partial windings 641 and 642, are connected in the direction + R, - S,

  
 <EMI ID = 28.1>

  
sé, are connected in the + R direction, the fifth and sixth partial poles are connected in the + R direction, - T, the seventh and eighth in the direction
- T, and so on.

  
A series 608 of partial poles fitted with windings, succeeds

  
 <EMI ID = 29.1>

  
a series 609 of wound partial poles. The free interval 606 can also be subdivided into several partial free intervals, which can be distributed more or less regularly along the periphery of the station.

  
 <EMI ID = 30.1>

  
tation that we want to obtain.

  
An action similar to that of a distributed winding is also obtained, as indicated above, when the partial poles of the different phases are appropriately reversed.

  
The irregular distribution of the poles offers the advantage of making it possible to obtain abnormal speeds of rotation, without introducing abnormally large slips or abnormal frequencies, and without having to use mechanically removable poles, and this under economically better conditions than 'using a three-phase motor of a known type, operating with a high slip.

  
Figure 51 schematically represents the development of a three-phase asynchronous machine. The stator is represented in 737 and comprises
36 salient poles 738 provided with concentric windings 700. The poles are numbered from 1 to 36. Depending on the coupling of these poles, different values of the synchronous speed are obtained. Figures 52 to 68 represent, below poles Nos. 1 to 36, different possible couplings, in such a way that the windings connected to phases + R or - R, for a three-phase network R, S, .T., Are indicated by horizontal hatching, those connected to the + T or - T phases by oblique hatching and those connected to the + S or - S phases by cross hatching.

   This arrangement can be switched to obtain various rotational speeds, as explained later, with this characteristic that, unlike known winding switching devices, the wavelength of the rotating field must not be a submultiple of the peripheral length of the stator. In addition, it is possible to obtain intermediate positions for which the perimeter of the stator is an integer multiple of the wavelength of the rotating field.

  
In figure 52, the poles are connected successively, in groups of 6 consecutive poles, to the phases + R, - T, + S, - R, + T, - S.

  
The rotor, fitted with a cage winding (shown at 739 in figure

  
1) possesses at 50 per / sec. a synchronous speed of 3000 revolutions / minute.

  
In the coupling according to FIG. 53, the R and T phases each receive 6 poles, and the S phase only 5. The N [deg.] S poles 35 and 36 remain un excited. Compared to the coupling of Figure 51, the wavelength of the rotating field is reduced by 1/18. The perimeter, therefore, is not an integer multiple of this wavelength, but there remains a

  
 <EMI ID = 31.1>

  
2840 revolutions / minute.

  
In the coupling of Figure 54, phase T, too, has one pole less. The wavelength of the rotating field is reduced by 1/9, and a synchronous speed of 2670 revolutions / minute is obtained.

  
In figure 55, each phase has only 5 poles. The wavelength of the rotating field is therefore reduced by 1 / 6th. The

  
 <EMI ID = 32.1>

  
2,500 rpm.

  
In figure 56, the R and T phases each have 5 poles, but the S phase only has 4. We therefore obtain a new shortening of the wavelength of the rotating field, and a synchronous speed of 2340

  
 <EMI ID = 33.1>

  
tervales not excited, we can nevertheless, as indicated in dotted lines, reconnect poles n [deg.] s 29 to 33 to phase + R. We only have to imagine the windings as a traveling field of a determined wavelength, which is not an exact submultiple of the periphery of the stator. This traveling field is cut out in such a way that the interval containing the non-excited poles is not too large; it does not matter, moreover, whether the various phases are distributed equally or not.

  
In figure 57, the phase R has 5 poles again, and the pha- '

  
 <EMI ID = 34.1>

  
minute.

  
In Fig. 58, the three phases have only 4 blades, and a synchronous speed of 2000 revolutions / minute is obtained.

  
In figure 59, phase S has only 3 poles. A synchronous speed of 1840 revolutions / minute is obtained.

  
In figure 60, phase T also has only 3 poles. A speed of 1670 revolutions / minute is obtained.

  
In figure 61, the three phases have only 3 Pales. A speed of 1500 revolutions / minute is obtained. Here, again, the wavelength of the rotating field becomes again an exact submultiple of the periphery of the rotor, and all the poles, therefore, can be excited, as shown in Fig. 62. The torque, therefore, is doubled from the excited <EMI ID = 35.1>, and the un-excited interval would also reach half of the perimeter. So that in the couplings corresponding to FIGS. 57 to 60 the unexcited interval is not too large, it is possible to connect, as indicated in dotted lines, the poles of the remainder of the perimeter to the corresponding phases. In this way, the motor torque is increased to a certain extent, and the magnetic traction force is distributed more evenly over the periphery.

  
In figure 63, phase S has 2 poles; in the figure
64, phase T now only has 2, and in FIG. 65, phase R also has only 2. The speeds are 1330, 1170 and 1000 revolutions / minute, respectively.

  
In FIG. 65 it is again possible, as indicated in dotted lines, to excite the entire periphery of the stator, because the length of the rotating field has once again become a submultiple of the perimeter.

  
In figure 66, the number of poles of phase S is reduced

  
to 1; likewise in figure 67 that of phase T, and in figure 68, that of 3 phases. The speeds are then 835, 670 and 500 revolutions / minute.

  
By virtue of such a switching of the poles, therefore, a whole series of different synchronous speeds is obtained. These are, of course, only fictitious theoretical values, which can be more or less reduced due to damping, losses by harmonics, etc ... The practical figures are therefore lower, but the variations due to

  
however, the load is considerably smaller than when it is desired to modify the various service characteristics of known asynchronous motors by modifying the slip, for example by varying the rotor resistance.

  
In order to obtain, in spite of the salient poles and the concentric windings, an action, with regard to the rotating field, analogous to that of a distributed winding, as mentioned previously, it is possible, as shown in the figures 50, 69 and 70, also provide two windings on each of the poles, and part of the poles can be connected, by these windings, to different phases. Thus for example, for the coupling corresponding to figure 52, for the speed of 3000 revolutions /

  
 <EMI ID = 36.1>
- T, + R, those of poles n [deg.] S 10 to 12 at phases - T, and so on. For the coupling corresponding to that of figure 58, for the speed of 2000 <EMI ID = 37.1>

  
those of poles n [deg.] s 11 and 12 to + S, and so on.

  
If one wants to provide the poles only with non-subdivided windings, in order to obtain simpler couplings, one can for example, instead of the coupling represented by figure 69 for the speed of 2000 revolutions / minute, use the coupling shown in Fig. 70, in which the poles connected to the different phases are appropriately inverted. In this case, the pole N [deg.] 1 is connected to + R, the second to - S, the third

  
and the fourth to + R, the fifth to - T, the sixth to + R again, the seventh and eighth to - T, etc. Also in this case, an action analogous to that of a distributed winding is obtained because the fluxes of poles n [deg.] S 1 and 2 or 5 and 6 always mix somewhat.

  
Obviously, disturbances occur in the residual elements of the perimeter and in those of the ends of the excited series, when the wavelength of the rotating field is not a sub-multiple of the stator perimeter, and these disturbances lead to a reduction in the torque. and performance. These disturbances, however, remain within permissible limits, when one takes into account that the speed control devices, known for asynchronous machines with the aid of additional sliding resistors, also lead to an increase in losses. An excessively strong reduction in torque can be remedied, such as

  
shown for example in Figures 56 to 60, in dotted lines, by following one or more complete rows of poles with an incomplete row, partially filling the remaining gap. It should be noted, moreover, that for groups for which the moment of resistance increases in proportion to the square of the speed, the decrease in the motor torque, when switching to lower speeds, has no practical significance, because for such groups, the power of the driven machines decreases much more sharply than the torque, which the engine is capable of delivering. Different driven machines require constant torque drive motors.

   In this case, the motors must have characteristics such that the minimum torque is sufficient, that is, in such a way that the machine is too powerful for the. full speed synchronous. For machines which require constant power, it is necessary to be willing to use motors that are much too powerful, when a large range of speed variations is desired. This can be simplified by providing a gear reducer, which for low rotational speeds allows better use of the drive motor. If intermediate gearboxes are provided, as is the case with most machine tools, then there is no longer any difficulty when the pole switching is properly combined with that of the variable speed drive.

  
FIG. 71 represents a synchronous generator, the stator system of which, which is its AC part, is made up of sectoral elements 801 each comprising 6 salient poles 802. Such a sector is represented on a larger scale by FIG. 72. Each one is represented on a larger scale. of the poles 802 has a concentric winding 803. In machines for three-phase current, the poles follow one another, again in the direction + R, - T, + S, - R, + T,
- S. Instead of having only a single winding, some or all of the poles can also have two or more partial windings, with inverted coupling such that they have, from the magnetic point of view, an action analogous to that of a distributed winding.

   In order to reduce the air gaps as much as possible, it is possible, as in the case of FIGS. 22 to 27, to interpose between the poles of shims 804, the edges of which are magnetic. The windings can be impregnated with insulating solutions, or even be provided with rigid insulating casings. It becomes, in this way, possible to insulate the coils in such a remarkable way that the generator can be used to supply high-voltage current directly, without having to insert an intermediate step-up transformer, as long as the '' is applied to the surfaces of the coils, in order to avoid efflu- <EMI ID = 38.1>

  
soaking or any other process. The electrostatic field then only manifests itself in a solid dielectric, and any formation of effluvia and sparks is avoided.

  
 <EMI ID = 39.1>

  
ment high, so that for a machine of this kind the short-circuit current can be reduced to a value approximately half that which would normally be obtained by an equivalent machine with distributed winding. By subdividing the windings into partial windings and mixing these partial windings, as explained previously, the reduced reactance. A subdivision of the winding into three parts makes it possible to obtain a reactance having a value substantially equal to that of a distributed winding.

  
The subdivision of the alternating current part into relatively small sectors 801 also offers the advantage that, in the event of significant temperature variations, there is no expansion of the sheets sufficiently large to be able to endanger the casing or the windings. The very slight geometric changes occurring within such a polar system therefore have no influence, as each polar column carries a closed winding, which does not undergo any

  
 <EMI ID = 40.1>

  
They are rigid, and their protrusion can be kept as low as desired; they can even lean directly on the sheets, so that they easily withstand large short-circuit currents, without requiring special reinforcements. It makes sense that the different sectors are much more manageable for machining, assembly and transport than, for example, machines which can only be dismantled in two parts. These sectors can moreover be machined on relatively small machine tools, the tools of which are guided in correspondence with the curvature of the sector.

  
For the assembly of these generators in power stations, it is possible in certain cases, if one wishes to avoid the large castings or welded parts, to fix the pole segments with the aid of rails or joists in structures made of non-metallic materials , such as concrete, cement, etc. As in low-head hydraulic power plants, the

  
 <EMI ID = 41.1>

  
intended to receive the sectors can be made very easily using a rotating jig. This housing can be part of the concreting of the plant. The securing parts of the sectors, and the sectors themselves, can also be easily produced using a rotating jig, so as to obtain the same air gap everywhere. This eliminates the need to manufacture, transport and assemble large casings, cast or welded, as the casing can be made on site using non-metallic materials. The refrigeration channels or the refrigeration pipes or the like can be made from these materials without difficulty.

  
To reduce the risk of damaging the insulation of the windings during transport, the packages of sheets can be transported separately.

  
and windings, and only assemble them on site. In the event of damage to a winding, or of any other defect, the various sectors or. the coils. For the same reasons, such a generator can easily be modified for other voltages.

  
The rotor of such a machine can be constructed in the usual manner, thus, for example, having salient poles 805 with direct current windings 806, which are connected via a ring collector to an exciter.

  
By an appropriate choice of the field curves of the excitation poles

  
 <EMI ID = 42.1>

  
disturbing fluence of salient poles and concentric windings on the sinusoidal voltage curve can be further reduced by moving the ac poles and the excitation poles relative to each other, when coupling coils in series or of groups of coils of the same phase, that is to say by ensuring, for example, that in one of the polar divisions, the axis of the excitation pole coincides with the axis of the pole corresponding to phase + R, that in the next polar division it is shifted for example by 5 electrical degrees, and that in the next polar division it is again shifted by 5 more electrical degrees, and so on.

   The partial voltages induced in the coils connected in series are then slightly out of phase with one another, and this phase shift is chosen so that the upper harmonics of the voltage curve are minimum.

  
While in the embodiment according to Figures 71 and
72 the alternating current part is subdivided into several sectors each comprising several poles, in the examples which follow, this alternating current part is subdivided into separate poles or into pairs of poles. In figures 73 and 74, the alternating current part is constituted by

  
 <EMI ID = 43.1>

  
quote 810, arranged on wheels 811. The different poles follow each other again in the same direction as in figure 72. Thanks to this subdivision of the alternating current part into separate elements, the workpieces to be machined and transported are even smaller , and can be manipulated

  
and packaged even easier. The different elements as well as

  
the parts necessary for their fixing are all identical and uniform. They can therefore be mass produced. As a result, there is this appreciable advantage that now, even for the largest generating machines, piecemeal manufacturing, which is costly and achievable only by highly skilled labor, can be replaced by very inexpensive mass production. which no longer requires specially qualified personnel, and which can be used for the manufacture of generators even if they have different dimensions, speeds, powers or other characteristics, the same individual elements, and obtain different voltages thanks to to a suitable coupling of the coils.

  
For decomposition into individual poles, the windings can be even better insulated, and perhaps even be joined, glued, or cast solidly with the cores. In this way, the movement of the windings relative to the core is avoided, for example under the influence of mechanical oscillations, electrodynamic forces, etc., and therefore fatigue or wear of the insulation. In some cases, the windings can be wound directly onto the core.

  
The U-shaped elements 807 can be made in different ways. A preferred embodiment is shown in Figures 75 and 76. In these, the pole pieces 871 and the yoke pieces 870 are laminated in directions perpendicular to each other. For this reason, it is possible to widen the poles 809 in the plane of rotation, without using magnetic shims, while retaining the possibility of manufacturing the windings 808 separately. The parts 870 and 871 are then held with the aid of suitable flanges 872 by weld seams, rivets or screws. The magnetic seals can be the subject of sawtooth cutting, to increase their permeability to flow, or else be filled with a paste containing iron particles, to reduce their reluctance.

   In Figure 76, pole columns 871 are T-shaped, and windings 868 are wound directly onto the pole pieces. The parts 870 and 871 are assembled using flanges 872, their borders 873 surrounding the heads 874 of the parts 871.

  
A particularly advantageous embodiment is represented

  
 <EMI ID = 44.1>

  
elements are substantially prismatic. The windings 813 are wound directly on the cores 812. The cores are fixed by the medium 814 or by the pole ends. The excitation poles 815 are disposed laterally with respect to the elements 812 and 813, and may, as shown in figure 79, rest on forks, or be fixed on a U-shaped rim 816. This embodiment provides this. advantage that the length of the magnetic circuit and the volume of the alternating current part are significantly smaller than those of the excitation poles and that, consequently, a large quantity of sheets can be saved, while significantly reducing the losses in the iron .

  
 <EMI ID = 45.1>

  
analogous with the help of individual elements. It is thus possible, for example as shown in FIG. 79, to provide on the wheel 817 U-shaped parts 816 each comprising two excitation poles 815, and in certain cases also to produce the wheel 817 using individual elements.

  
A particular advantage of the decomposition into individual elements is that the ratio of areas to volumes becomes much greater than for non-decomposable machines and that consequently the areas available for heat removal are significantly increased, given that, if we decrease the dimensions of a body, its volume decreases proportionally to the cube of its dimensions, while its area decreases only in proportion to the square. It follows therefore that the decomposition into individual elements results in exceptional cooling, because the large machine behaves as if it were made up of several small machines.

   As currently small machines do not usually include a cooling device or air circulation ducts, it can in certain circumstances also be waived with regard to the subject of the invention. However, there is no difficulty in creating air circulation.

  
cooling between the individual elements, as is done for

  
large machines, this circulation, due to the subdivision of the machine into individual elements, being much more efficient than in the case of non-decomposable machines. It is possible to provide in or between the individual elements, especially when these are held in concrete,

  
in cement or the like, refrigeration pipes traversed by a stream of water, instead of or in addition to the reinforcements, so as to further increase the cooling, and the individual elements can even be welded to the cooling pipes, so that these pipes also serve to hold the elements in place.

  
When assembling a machine according to the invention, the assembly by welding provides a great advantage. It is thus possible, by way of example, to put the individual elements in place, during assembly, by using a template guided by the shaft of the machine, and by welding them to the pieces of iron emerging from the concrete. Their correct placement is therefore ensured.

  
In the exemplary embodiment according to FIG. 81, the individual elements 812 of the alternating current part are mounted on the rim of a wheel 818, and rotate; they are electrically connected by the collec-

  
 <EMI ID = 46.1>

  
the rotor is relatively light, because the iron volume of the AC part is very small.

  
In rotating field machines (differential transformer) according to figures 82 and 83, the rotor and stator also consist of individual elements 901 with U-shaped magnetic cores 902

  
and concentric windings 903. The stator elements can for example be anchored in the foundations of the machine, in the case of a machine

  
with a vertical shaft, for example by embedding rails in foundations; the individual elements, after being put in place using a rotating jig guided by the machine shaft, are welded to the free end of these rails. The rotor elements are mounted on an impeller 905 which is itself mounted on a shaft 904. The shaft has a slip ring 906, connected to the individual elements. Shaft 904 is connected, in accordance with a known construction method, to a separately controlled drive or braking device. To avoid stopping the drive device in the event of stopping of the shaft, it is possible, in the known manner, to provide a differential. The individual elements are again coupled in the direction + R, - T, + S, - R etc. as shown in figure 83. They have polar expansions 907 widening.

  
 <EMI ID = 47.1>

  
whose edges are magnetic.

  
U-shaped pieces of iron may consist of bundles of sheets. The yokes and pole columns can also be made up of separate packages of sheets, assembled by press or by interlocking.

  
We can assemble the different packages of sheets by welding, bolts,

  
by rivets, by crimping, etc. As shown in figure 83, the elements

  
of the rotor are offset from those of the stator, for reasons indicated above, and the number of poles of the rotor is different from that of the

  
stator.

CLAIMS.

  
1.- Rotating field machine, characterized by the combination

  
of the following characteristics: salient poles with concentric windings of an arrangement such that the poles of the same phase, but of opposite polarity, are offset by 1800 (calculated according to the pole pitch) one by one

  
compared to the other, rotor with cage winding or damping winding, preferably low resistance, or other means to reduce

  
influences of the upper harmonics or the upper harmonics themselves, and rotor poles or notches preferably arranged at an angle.


    

Claims (1)

2.- Machine according to claim 1, characterized in that the number of notches in the rotor is independent of the number of poles. 3.- Machine according to claims 1 and 2, characterized in that the poles have a shape such as the curve of the field, to the right of each polar expansion, or substantially rectangular. 4.- Machine according to claims 1 to 3, characterized in what the pole recovery factor is determined for the conditions optima. 5.- Machine according to claims 1 to 4, with disc armature (one or more discs) characterized by poles or pole expansions in the form of a sector. <EMI ID = 48.1> for small powers, in particular less than 150 W. 7.- Machine according to claims 1 to 6, characterized in what the poles of the different phases (R S T) or of the auxiliary phases consist of two or more partial poles (see 12, figures 4 to 6) <EMI ID = 49.1> 8.- Machine according to claims 1 to 7, characterized in that at least some of the partial poles (12, figure 5) have partial windings (31, 32), which are connected to different phases (R, S, T) according to an arrangement such as it results, from the point of view of the rotating field, an action similar to that of a distributed winding. <EMI ID = 50.1> that the partial poles (12, figure 6) of the different phases R, S, T are, at least in part, inverted so that from the point of view of the field turning we obtain an action similar to that of a. distributed winding. 10.- Machine according to claims 1 to 9, characterized in that a crown of solenoids (101) (see figures 8 to 10) is arranged between two disc-shaped rotors (104, 105) provided with cage windings. llo- Machine according to claims 1 to 10, characterized in <EMI ID = 51.1> solenoid or a first group of solenoids, a first disc rotor (104) a second solenoid or a second group of solenoids and the other disc rotor (105). <EMI ID = 52.1> that the solenoids (101, figure 9) are trapezoidal in shape throughout less to the polar expansions (103), and are optionally composed of sheets arched in accordance with the perimeter of the rotor. 13.- Machine according to claims 1 to 12, characterized in that the solenoids (101) are held by the two pole expansions (103, figure 16), or, in the case of subdivided windings, (120, 121, figures 10 and 11), by the middle (107) or by several places (see figure 18). 14.- Machine according to claims 1 to 13, characterized in that the solenoids are held together by means similar to manifold lamellae, producing an arching effect. <EMI ID = 53.1> in that the solenoids (101, figures 9 and 10) are held in place with the interposition of filling pieces (111, 113) by means of shrinking rings (109) or clamping (110) and are fixed to the casing (112) preferably using these rings (109, 110) 0 <EMI ID = 54.1> Sée in that the solenoids (101, Figures 9 and 10) are wedged between an inner ring, (108) and an outer ring (109, 110). 17.- Machine according to claims 1 to 16, characterized in that the clamping rings consist of wire ties (109, figure 16). <EMI ID = 55.1> that the solenoids (101) are screwed, welded, wedged or fixed in some way to an interior support part (115, figure 13, or 108, figure 14) or external (envelope 112, figure 15) 0 <EMI ID = 56.1> that the solenoids, with a view to their holding in place, are, embedded, pressed or injected into the mass in the process of solidifying or setting, as the case may be, together with the casing or another support part. 20.- Machine according to claims 1 to 19, characterized in that the fan fins (118) are arranged outside or at the ends of the two disc rotors (104, 105, Figure 17), and in that these fins suck fresh air through openings (119) located near the center of the envelope, and rejects it through radial (125) or axial (126) openings at the ends of the envelope, after it has circulated between the solenoids (101). <EMI ID = 57.1> what a fan (118), disposed on the outer side of a disc-rotor (105) (figure 18), sucks in cooling air through one end of the casing (at 128) and rejects it at the other end of the casing (at 126) after it has circulated between the solenoids (101). 22.- Machine according to claims 1 to 19, characterized in that the fans (129, 130) (figure 19) arranged on the inner side of the disc-rotors (104, 105, figure 19), or else between them, suck cooling air, by the outer sides of the envelope in (131) and reject it by passing it between the 'solenoids (101) through openings (119) located in the middle of the envelope. 23.- Machine according to claims 1 to 19, characterized in that a fan, arranged on the inner face of a rotor disc sucks cooling air through one of the flanges of the casing, and rejects it through the other flange, after it has passed between the solenoids. 24. Machine according to claim 1, characterized in that the pole columns are arranged in groups which are substantially parallel (201 to 203, and 204 to 206, FIG. 20). 25.- Machine according to claims 1 and 24, characterized in that all the pole columns (201 to 206, FIG. 20) are arranged in parallel and constitute two groups (201 to 203 and 204 to 206) offset by 180 [deg.] /. 26.- Machine according to claims 1, 24 and 25, for use in two different fluids, characterized in that a wall (211) of a capsule (212) surrounding the rotor space is arranged between the pole windings (206 ), (figure 20) and the polar expansions (210). 27.- Machine according to claims 1 and 24 to 26, characterized in that the polar expansions (210, figure 20) are separated from the polar columns by an interval in which the wall (211) of the capsule passes. 28.- Machine according to claims 1 and 24 to 27, characterized in that the intervals of each group of poles (201 to 203 and 204 to 206, figure 20) are arranged in the same plane. 29.- Machine according to claims 1 and 24 to 27, characterized in that the crown of the polar expansions consists of a heterogeneous ring (tube 218, fig. 20) constituting with the polar expansions magnetically conductive areas and with the polar gaps, magnetically non-conductive areas. 30.- Machine according to claims 1 to 29, characterized in that the polar intervals (302, figure 22), the dimensions of which are equal to or less than those of the "day" of the windings (305) are filled by shims (304 ) formed along the edges (340, 341 ,, Figure 23; 310, figure '25; 311, figure 26; 313, figure 27) by magnetic materials. <EMI ID = 58.1> in that the middle area (309, Fig. 25) of the wedges is made of rubber, which is vulcanized on the marginal areas (310). 32.- A method of manufacturing shims according to claim 31, characterized in that the sheets constituting the edges of the shims (310), (Figures 24 and 25) are vulcanized on the rubber part (309), while they l 'surround, for example in the form of a ring, the sheet metal parts which connect the two edges of the wedge then being removed. <EMI ID = 59.1> stamping waste (307, figure 24) from the stator sheets are punched at the place where the rubber part (309 to 308) will subsequently be placed and are then used as a single part, in accordance with the method according to claim 32. <EMI ID = 60.1> the use of agglomerated wedges (see figures 26 and 27). 35.- Machine according to claims 1 to 30 and 34, characterized in that the edges (313, Figure 27) of magnetically good conductive powders and the middle zone (314) of insulating powders, in particular of ceramic materials, are agglomerated in a unique piece. 36.- Machine with salient poles provided with pole expansions according to claim 1, and coming into contact with the other parts of the stator and of the pole pieces, forming magnetic seals, characterized <EMI ID = 61.1> to increase the surface of the joints. 37.- Machine according to claims 1 and 36, characterized in that the poles (401) (Figures 28 to 33) penetrate like tenons into the corresponding parts (403) of the cylinder head. <EMI ID = 62.1> in that the poles (401 Fig. 33) penetrate like a dovetail in the parts (403) of the cylinder head. 39.- Machine according to claims 1 and 36 to 38, characterized in that the tenon-shaped ends of the poles are split (in 402, see figures 28 and 30) to constitute a spring. 40.- Machine according to claims 1 and 36 to 39, characterized in that the poles (401, Figure 34) widen in the form of a T at the contact points. 41.- Machine according to claims 1 and 36 to 40, characterized in that the T-shaped enlargements of the poles (401, Figures 35 to 37) constitute sectors of the cylinder head (403). 42.- Machine according to claims 1 -and 36 to 41, characterized in that the poles (401, Figure 37) are serrated where they touch (419). <EMI ID = 63.1> terized in that the parts constituting the poles and the cylinder head (401, 403, <EMI ID = 64.1> 44.- Machine according to claims 1, 36, 41 and 42, characterized in that the parts constituting the yoke and the poles (401, 403, Figures 36 and 37) are held together by arching effect in an envelope (417), using wedges (416), by hooping rings (418), ligatures or other devices of this kind. 45.- Machine according to claims 1 and 36 to 44, charac- <EMI ID = 65.1> wedges (408) or similar devices driven between their polar expansions (409). <EMI ID = 66.1> Sée in that the poles (401, Figures 31 and 32) are fixed to brackets (410) or similar devices surrounding the cylinder head. 47.- Low power machine for three-phase connection, according to claim 1, characterized in that it comprises four salient poles with concentric windings (501 to 506, Figures 38, 39) in Scott assembly. 48.- Machine according to claims 1 and 47, characterized by an internal cruciform stator (509, Figures 40 and 41) with rectangular notches, preferably square, to receive the windings (401 to 406). 49.- Machine according to claims 1 and 47, characterized by a rectangular external stator (510, figures 44 and 45) with two pairs <EMI ID = 67.1> 50.- Machine according to claims 1 and 47, characterized by a square outer stator (510, Figures 46 and 47) with polar columns (511) eccentric and polar expansions (512) arranged on the same side of the poles, preferably with locations, to receive the coils, which are identical for all the poles. <EMI ID = 68.1> the poles are irregularly distributed, in order to obtain abnormal rotational speeds. 52.- Machine according to claims 1 and 51, characterized in that an interval without winding or not excited follows a series of wound poles (for example 603, Figure 48). <EMI ID = 69.1> that the pole steps of the different phases are different. 54.- Machine according to claims 1 to 7, characterized in that the poles are also switchable so that the wavelength of the rotating field is not contained an integer number of times in the perimeter, that is to say say so that the perimeter is not a complete multiple of the wavelength of the rotating field (Figures 50 to 70). 55.- Machine according to claims 1, 7 and 54, characterized in that the poles which correspond to the "remainder" of the periphery are short-circuited or are not energized (for example, figure 55). 56.- Machine according to claims 1, 7 and 54, characterized by a coupling such that parts of the "remainder" of the periphery are connected to only part of the plases (for example, Figure 59, part in broken lines). <EMI ID = 70.1> wave of the rotating field, the pole steps of the different phases are of different magnitudes (for example, figure 63). <EMI ID = 71.1> terized in that the unexcited interval corresponding to the "rest" of the perimeter is subdivided into two or more intervals, preferably evenly distributed on the perimeter, in order to avoid unilateral magnetic forces or similar effects. 59.- Machine according to claims 1, 7 and 54 to 58, characterized by its use on receiving machines of which the resistive torque increases with the speed of rotation, for example according to the square thereof. 60.- Machine according to claims 1, 7 and 54 to 58, characterized in that the switching of the poles is combined with a speed changing device, especially for machines with constant torque or constant power, in particular for low speeds of rotation. 61.- Application of the method of construction of the alternating current part of electric machines consisting of pole supports - preferably individual elements with salient poles - and preferably with concentric windings according to claims 1 etc ... to large AC machines, especially large synchronous generators for low-head hydraulic power plants (Figures 71 to 81). 62.- Machine according to claims 1 and 61, characterized in that the elements are constituted by sectors comprising several (eg 6) salient poles (Figures 71, 72). <EMI ID = 72.1> in that the elements are constituted by solenoids or the like with magnetic cores arranged transversely with respect to the direction of rotation, and the pole ends of which face two rings of excitation electros (for example FIG. 77). 64.- Machine according to claims 1, 61 and 63, characterized in that the volume of sheets and the length of the magnetic circuits of the alternating current part are notably lower than those of the excitation pole part (compare figure 77) . 65.- Machine according to claims 1, 61, 63 and 64, characterized in that the magnetic cores of the alternating current part have a U-shape (figure 73). 66.- Machine according to claims 1, 61, 63 and 64, characterized by rectilinear magnetic cores of the alternating current part and by excitation pole rings arranged on both sides of the magnetic cores (figure 77). <EMI ID = 73.1> characterized in that the excitation poles, the axes of which are parallel to the axis of the machine, are arranged inside U-shaped sections constituting a rim (figure 79). <EMI ID = 74.1> characterized in that the magnetic cores of the alternating current part are located on the rotor, and are fixed there preferably by the middle or by the ends, while the excitation poles are stationary. (figure 81). 69.- Machine according to claims 1, 61, 63, 64 and 66 to 68, characterized in that the excitation pole part is also constituted by an assembly of individual magnetic cores in approximately U shape. (figure 81). <EMI ID = 75.1> This is because the fixed elements can optionally be held in non-metallic materials, such as concrete, cement or the like, using bars, profiles, etc. <EMI ID = 76.1> ized in that the windings of the alternating current electros are coupled in whole or in groups in series, and in that the excitation electros and the alternating current electromagnets are distributed with respect to each other d In an irregular manner such that the disturbing action of the concentric windings and salient poles on the sinusoidal shape of the voltage can be compensated, at least approximately. 72.- Application to rotating differential transformers (asynchronous machines), in particular for coupling networks, of a construction of the alternating current part of electric machines, consisting of pole support, in particular of individual elements (901, figures 82, 83) with salient poles and concentric windings (903) according to claim 1 and following. <EMI ID = 77.1> or the like with magnetic cores (902) arranged transversely to the direction of rotation (Figures 82 and 83). 74.- Machine according to claims 1 and 72 and 73, characterized in that the individual elements (901) comprise U-shaped magnetic cores (902, figure 82). <EMI ID = 78.1> ized in that the individual elements are arranged in an insulating fluid <EMI ID = 79.1> in that &#65533; in order to obtain a sinusoidal voltage curve the number of individual poles contains as a factor the number of phases, but is not exactly divisible by the synchronous number of poles (f.60). not