RU2280941C2 - Electrical machine - Google Patents

Abstract

FIELD: electrical engineering; convertible electrical machines.

SUBSTANCE: proposed electrical machine that can run as motor and as generator producing heavy ac and dc currents has frame, frame walls carrying field windings, shaft mounted on bearings, rotor carrying armature currents, and slip rings with ring holders; novelty is that all like-polarity pole cores carrying field windings on frame are facing rotor; connected in parallel with main field winding is auxiliary field winding built of two series-interconnected coils with opposing magnetic fluxes; coils are mounted on special projections made on inner walls of frame concentrically relative to rotor shaft; rotor is divided along circumference into two equal parts with copper gasket in-between; they are pressed together by means of copper strips; a number of round holes are provided on rotor circumference; same quantity of slit-type holes are made closer to rotor in radial plane which accommodate U-shaped winding coils of rotor placed on one side of rotor; they are inserted with their one end into round holes and with other end, in slit-type ones; wire ends of each coil on opposite end of rotor are interconnected in series; finishing leads of each coil are also interconnected in series and common finishing and starting leads of rotor winding are connected to flat copper slip rings secured on rotor shaft, at left- and right-hand ends; they are held in permanent contact with fixed flat graphite rings by means of hold-down flat springs secured on frame walls; rings are insulated on shaft end from rotor and from frame walls. Graphite rings are connected by means of conductors to common terminals; rotor winding is connected in parallel with field winding.

EFFECT: simplified design, reduced size, enhanced power output, enlarged functional capabilities.

1 cl, 8 dwg

Description

The invention relates to universal unipolar electric machines designed to convert mechanical energy into electrical energy and, conversely, to convert electrical energy into mechanical energy.

An electric machine can operate as an electric motor from alternating single-phase current, which is very important, as well as from a pulse current of the same polarity.

As a generator, it allows to obtain direct current without switching high power.

The principle of operation of the electric machine in the motor mode is based on the known interaction of the magnetic field of the stationary stator cores with the field windings with the electric field of the rotor conductors, and in the generator mode - on the basis of electromagnetic induction phenomena arising between the stator electromagnets and the rotor windings.

The setting of the number of stator electromagnets and rotor winding conductors is not limited.

An electric machine can be widely used in household and industrial equipment, for example, for producing direct current, used in installations for electrolysis and electric welding, etc.

To obtain direct current, as a rule, direct current electric machines are used, the emf and current are rectified by using a collector and brushes, which greatly complicates the operation of the machine. At the beginning of the current / 1831 / century, a number of attempts were made to improve the brushless, unipolar machine, which was carried out by Faraday / cm. pg. 15-17. "Electric cars". Piotrovsky L.M. / Edited by A.R.Dero. L .: Energy, 1974. 7th edition /.

Fig. 1-6 of the mentioned publication shows one of the possible variants of a unipolar machine, which includes a bed with field windings mounted axially on the walls of the bed, a shaft with bearings, armature winding rods laid in a steel cylinder. The ends of the rods are covered at both ends of the anchor by contact rings with brushes.

Direction of the EMF induced in the conductors remains unchanged relative to these conductors during rotation of the armature, which allows you to get a constant current without switching.

Since in this case all the rods are connected in parallel, the voltage of the machine is determined by the emf one rod.

The main advantage of a unipolar machine is the absence of voltage ripples and simplicity of design.

The unipolar machine is the closest analogue in terms of design features and the principle of magnetic coupling between the moving and stationary parts of the proposed electric machine.

A disadvantage of the known unipolar machines is that they cannot be universal and are mainly used as a generator of low voltage / 5-40 V / and high current strength / 50 kA /. Power - up to several MW / cm. p. 521. Polytechnical Dictionary. Ed. "Soviet Encyclopedia". Moscow. 1977 /.

The proposed electric machine has all the mentioned positive qualities and, in addition, has versatility, can be used with high and low currents and voltages, everything will depend on the resistance value of the stator windings and the armature windings, on the connection circuit of these windings to sources - all this is not limited and allows you to make a wide selection when designing such electric machines. In addition, the supply and removal of voltage and current from the armature windings is carried out by means of slip rings located on the left and right sides of the rotor, which have a large contact area, which will ensure the reliability of the electric machine when applying and using large voltages and currents, excluding any kind of sparking and burning of working surfaces at rings.

Similar contact rings also cannot worsen the contact connection even if there is a need to increase the rotor speed, for example, to increase the voltage.

The proposed electric machine, in contrast to the prototype, has a gear stator magnetic circuit, made in the form of several / four / same-pole cores with field windings / the number of poles is not limited /, uniformly distributed around the circumference of the bed. The field windings are interconnected in series / as one of the options, there is practically the opportunity to connect the field windings in various ways /.

The proposed electric machine, in contrast to the prototype, has a magnetic rotor cog / cm. fig. 1-5, p.16, "Electric machines", 1974, L. Piotrovsky /, since the sections of the rotor winding are stacked in radial grooves, separated by radial slots, in which copper plates are laid, performing the role of two:

1 - serve as fasteners, pull together two halves of the rotor;

2 - break the integrity of the magnetic circuit in order to reduce losses from eddy currents and to exclude the occurrence of a closed magnetic field, the occurrence of which takes place in an annular coil, because that it is known that the magnetic field in the ring coil is concentrated inside it and almost absent outside it. In order to squeeze the magnetic field out of the core outward, to the gap, a deep groove is used, located closer to the center, in which the conductors with current having the opposite direction of movement are laid. As you know, with opposite directions of currents in the conductors, the conductors repel each other. If the conductors are rigidly fixed, then in this case repulsion will occur only between magnetic fields, which will be pushed to the gap.

The rotor has only an appearance with a smooth surface; in fact, the rotor contains deep grooves consisting of two holes located in the radial plane, and the upper hole has a cut of 35 / cm. figure 3 /, which also breaks the integrity of the magnetic circuit / in addition, the shape of the holes is also not limited /. / Fig. 1-5 shows the core of the anchor 4 with a toothed one, see page 16, “Electric machines”, L. Piotrovsky, but the rotor surface is smooth.? /

The sections of the rotor field winding are interconnected in series, which makes it possible to use an electric machine using higher voltages, however, the connection of the sections between themselves can be very different, also not limited.

The use in the proposed electric machine of additional stator field windings, which are the main ones, unlike the prototype, as well as the use of field windings on the rotor make it possible to use the machine as an electric motor that can operate from alternating currents of a single-phase circuit. When changing the direction of current flow in the windings of the rotor or stator, the electric motor has the ability to change the direction of rotation.

Magnetic current control crossing the rotor conductors is carried out by changing the current of the auxiliary excitation windings / BOB /. Changing the magnetic flux can be carried out over a wide range / from the maximum value to zero /, since the current in the auxiliary excitation windings / BOB / can be reversed, due to which the magnetic flux will completely stop and the rotor will brake. The stator field windings and the BOB windings operate on the same load, on the same magnetic flux. This allows, firstly, to increase the power of the magnetic flux, and secondly, it creates the opportunity to control the magnetic flux independently, without affecting other field windings, for example, the magnetization of the cores of the main field winding / OOB / will be saved, which will in turn allow you to transfer the electric machine from one operating mode to another, i.e. from engine mode to generator mode.

The problem to which this invention is directed is to increase power and achieve versatility. The electric machine contains several pole cores with field windings located by the same poles to the rotor.

All field windings of the pole cores are interconnected in series. Parallel to the main excitation winding, an auxiliary excitation winding is connected, consisting of two sections connected in series, and counter-magnetic fluxes. The sections are mounted on special protrusions made on the inner walls of the bed concentrically to the rotor shaft. All sections of the rotor are interconnected in series and installed in such a way that the direction of the currents has a one-sided orientation / from left to right /, as a result, all sections work simultaneously in a magnetic field, creating powerful torque / for motors / and high current density / for generators / .

The rotor is divided along the circumference into two equal parts, between which a copper gasket is installed and which are pressed together by copper strips. Several circular holes are made around the circumference of the rotor; closer to the center in the radial plane with round holes, the same number of slit-like holes are made in which sections of the rotor winding are laid and fixed. The blanks of the sections are made in a U-shape and all are laid on one side of the rotor. At one end they slip into a round hole, and at the other end into a slit-like hole. On the opposite side of the rotor, the ends of the wires of each section are connected together in series, the ends of each section are also connected in series, and the common end and beginning of the rotor winding are connected to contact copper flat rings fixed to the shaft on the left and right sides of the rotor, which are in constant contact with stationary graphite flat rings held by compression flat springs fixed to the stator walls. The rings are provided with insulation on the side of the shaft, rotor and the walls of the stator / bed /. Graphite rings are wired to common terminals. The rotor winding is connected in parallel with the field winding.

The proposed electric machine compares favorably with all known electric machines. It has powerful torque, is versatile, much easier to manufacture, there is no collector, it allows you to save the residual magnetization in the cores of the main field winding, which allows for reliable engine start and generator start-up. The auxiliary field winding can be used as a regulating element of the engine speed, and in the generator mode it can be used to control the magnetic flux in order to regulate the voltage supply.

The proposed laying of the U-shaped sections of the rotor winding will play a greater role than negative, as it might seem. If we consider that the interaction between the conductor with the current and the magnetic field occurs with maximum force only at a very small gap between them / 1-2 mm /, and at a distance of 10-15 cm the strong interaction ceases, then the proposed laying of the rotor winding sections will not have counteracting reaction. Conductors with reverse currents located in slit-like openings will interact weakly with magnetic flux, because they are removed from the strong interaction of the magnetic flux and immersed in the rotor body, and, in addition, the conductors are dispersed along the radial gap, therefore, the induced emf will dissipate, and part will act on the electric field of the conductors in the round holes and push it to the gap, similar to windings with a deep groove.

Figure 1 shows a section of an electric machine in the middle part along the circumference of the stator.

In Fig.2 shows a section of an electric machine along aa in Fig.1 complete.

Figure 3 shows the rotor, an end view.

Figure 4 shows a section of the rotor along aa in figure 3.

Figure 5 shows the rotor from the side of the circumferential surface.

Figure 6 shows the workpiece section of the rotor winding.

Figure 7 shows the workpiece section, view from the side.

On Fig shows a connection diagram of the field windings and the rotor winding.

The electric machine includes a frame 1 with two walls 2 and 3, a shaft 4 with a rotor 5 and bearings 6 and 7 installed in the walls of the frame, fixed by covers 8 and 9. Four pole cores 10, 11, 12 are fixed on the inner cylindrical surface of the frame , 13 with the main field windings / OOB / 14, 15, 16, 17 connected in series, the beginning and end of which are brought out 18 and 19 / Fig. 2/ and connected to common network terminals 20 and 21. All pole cores are turned with their same poles / N / to the rotor 5. On the inner walls of the bed are made special protrusions 22 and 23 concentrically to the shaft 4, on which the auxiliary excitation windings / BOB / 24 and 25 are located. The input end 26 of the auxiliary excitation winding 24 is brought out and connected to a common terminal 20. The output end 27 of the winding 25 is brought out and connected to a common terminal 21. The windings 24 and 25 are connected to each other in series, and relative to the main field windings, in parallel, while magnetic kami face each other oppositely homonymous characters / S /, 2 and 8. The main winding and the auxiliary excitation windings operate in one load at a magnetic flux.

Rotor core 5 / i.e. the rotor itself / is also assembled from steel sheets / not shown /, insulated from each other by varnish / or by other means / to reduce losses from eddy currents and heating, and is divided into two equal parts 28 and 29 / Fig. 5/ in the plane of the copper circle gasket 30 and are compressed together by transverse copper strips 31/3 /, passing between sections of the windings / for example, 32 and 33, Fig.3 / rotor. The main feature of the rotor device is the laying of the winding sections. For this purpose, several / 16 pcs. / Through transverse holes of circular shape 34 with slots 35 for the exit of the electric field are made around the circumference of the rotor. Accordingly, each circular hole is made closer to the center, in the radial plane, the same number of slit-like holes 36. The area of the cross-section of the holes should correspond to each other. On both sides of the rotor, for laying wires, made between the holes of the trough 37 and 38/4 /. Formed a whole section of the rotor between the holes 39/3 / serves as a core for each section / see 28 and 29, FIG. 4 /, which will increase magnetic induction, since it is known that when a metal core coil is placed in the magnetic field, the magnetic induction increases many times.

6 and 7 show one blank of the rotor winding section. It is a dissected coil of wire, the ends of which are laid in the corresponding insulation 40 and 41 and are molded in a U-shape, as a result, one end of the section becomes round and the other flat. With the round end, the section is pushed into the round hole, and with the flat end into the slot-like hole (Fig. 3 and 4), respectively. The sections are laid on one side of the rotor / cm. figure 3, the upper part of the rotor /.

After laying the sections, the wires in each section are connected in sequential order. For the convenience of finding the ends, a small voltage / 24 V / is applied to the input of the first / any of them / wire 42 / Fig. 4/, then its end 43 is found and connected to the beginning of the second wire 44, then the end 45 is connected to the beginning of wire 46 and t .d. The end 47 is with the beginning of 48. The end of 49 is with the beginning of 50. The end of 51 is with the beginning of 52, and the output end 53 of one section is connected to the beginning 54 of the second section, etc. Output 55 is connected to the beginning of 56. Output 57 is to the beginning of 58. Output 59 is to the beginning of 60. Output 61 is connected to the next adjacent section 6 / po. account in figure 3 /, 7, 8, 9, 10, 11, 12 and 13 and then to input 78. Output 79 - with the beginning of 80. Output 81 - with the beginning of 82. Output 83 will be the end of the rotor winding. In Fig. 3, there are no sections in the lower half of the rotor, and the count corresponds to all sections in order. The output end 83 is connected to a flat copper ring 84, which is mounted on a shaft on the right side of the rotor 5/2 /. The ring is insulated 96 on the shaft and rotor sides. The ring has a working side surface, which is in constant contact with the working side surface of a stationary flat graphite ring 85, which is held in a fixed position on four sides by a compressing flat spring 86, mounted 87 on the wall of the bed 3.

The carbon ring has insulation on the side of the shaft and compression springs. The carbon ring is connected to a wire 88, which is brought out and connected to a common terminal 21/2 /. The input end 42 / Fig. 3/ is connected to another copper flat ring 89, mounted on the shaft on the other side of the rotor, and is also isolated from the shaft and the rotor, its working surface is in constant contact with the working surface of another carbon ring 90, held from four sides with flat spring springs 91 fixed to the stator wall 2. The carbon ring also has insulation on the side of the shaft and compression springs. The carbon ring is connected by a wire 92 with a common terminal 20/2 /.

The wires of each section (Fig. 6 and 7) are molded in a U-shape 93 and laid in sockets 37 and 38, and the excess ends 94 and 95 are cut, insulated, sealed, fixed and filled with sealant or the like. The number 96 indicates places of isolation.

As a result of one-sided laying of sections and their serial connection to each other, the direction of current flow in all active conductors has a one-sided direction, from left to right / shown in Fig. 5 /, and in conductors laid in slit-like openings, the current moves in the opposite direction / cm. figure 1, where the cross shows the movement of current from us, and the point - to us /. This arrangement of currents in sections of the rotor winding will correspond to the operation of the electric machine in electric motor mode, if the rotor rotates the shaft in the direction of the arrow, Fig. 1.

When the electric machine is operating in generator mode, the rotor rotation and the direction of the magnetic flux will remain the same, and the current direction in the rotor winding will be reversed, therefore, to avoid demagnetization of the cores on the stator excitation windings, it is necessary to swap the ends of the rotor winding.

To put the electric machine into AC generator mode, it is necessary to break sixteen sections of the rotor winding into four groups of four sections in each group. Sections included in the first group / 1, 2, 3, 4 / and in the third group / 9, 10, 11, 12 /, remain with the same current direction, and in sections included in the second group / 5, 6, 7, 8 / and in the fourth / 13, 14, 15, 16 /, the current is turned on in the opposite direction, for which these sections need to be reversed.

The operation of the electric machine in electric motor mode.

When applying alternating or pulsed current to terminals 20 and 21 (Fig. 2/), the current will go in three parallel ways.

On the first path, the current will go from terminal 20 to wire 18 through the main field windings 14, 15, 16, 17 / Fig. 1/ and to the output wire 19 and terminal 21 / Fig. 2/. The pole cores 10, 11, 12, 13 will be magnetized and create four magnetic flux with a direction to the center of the rotor with the same pole / north /.

On the second path, the current will go from terminal 20 to the input wire 26 of the auxiliary excitation windings 24 and 25 / BOB / and then through the output wire 27 to terminal 21. The current passing the auxiliary excitation windings will create a magnetic flux in the windings, the vector of which will coincide with vector of magnetic flux coming from the main field windings. Since the auxiliary excitation windings 24 and 25 are turned on counter-magnetic fluxes, the magnetic flux from the main excitation windings will go through the rotor in two ways, separated by a copper strip 30/2 /. The first magnetic flux F1 from the north poles of the magnetic cores on four sides, crossing active wires laid in round holes on the left side of the rotor (Fig. 5/, rotor shaft 4, protrusion 22 of the auxiliary winding 24 / Fig. 2/, through the left wall 2 bed and then the magnetic flux will close at the south poles of the cores 10, 11, 12, 13. The second magnetic flux F2 will also go from the north poles of the cores 10, 11, 12, 13, crossing the active wires laid in round holes, and then on the right side rotor 29 / Fig. 5/, rotor shaft 4, protrusion 23 auxiliary gatelnoy excitation winding 25, through the right wall of the frame 3 and the magnetic flux will close more to the south poles of the cores 10, 11, 12, 13.

In the third way, the current will flow from terminal 20 through wire 92 to the fixed ring contact 90 and the movable ring contact 89 to the input of the first section 83 / Fig. 3/ of the rotor. Passing sequentially all sections / 16 pcs /, wire 42 and 88 / Fig.2/, the current will flow to terminal 21.

Thus, all three current paths are connected to the network in parallel. Since the active wires of the rotor winding, laid in round holes, are in a magnetic field, they will be affected by magnetic forces, and therefore the moment of forces relative to the axis of the rotor. Under the action of the torque, the rotor will rotate. Having a rotor on its circumferential surface, sixteen powerful bundles of active wires that are constantly in the magnetic field of the pole cores, interacting in conjunction with additional field windings, will create a powerful torque. On the other hand, additional field windings will magnetize their protrusions 22 and 23, which, interacting with the rotor shaft, will create a braking effect. The shaft as a rod in a coil with a current will be held motionless in a magnetic field and thereby provide resistance to torque. Since the radius of the rotor exceeds the size of the radius of the shaft many times, the reaction of the shaft will be negligible.

With the passage of current through the windings of each section (Fig. 3/ in the cores 39/16 pcs.), A magnetic flux "F" will be formed similar to a closed magnetic flux in an annular coil, which will create heating of the rotor. / It was established that in a ring coil a magnetic field is concentrated inside it and almost absent outside it /. To reduce this magnetic flux, each section is cut off from the adjacent copper plates 31/3 /, because it is known that copper plates somewhat inhibit the passage of magnetic flux, and as a result of this, the total magnetic field of one section 32 and 33 (Fig. 3/) will interact between two counter flows of two branches 32 and 33 of one section and will be extruded upward through the cut 35 of the round beam 33 together with the electric field 97. The separation of the sections into round and flat bundles of wires / 6 and 7 / is justified by the fact that the electric field in round bundles creates a stronger and denser than the electric field arising in flat bundles. Therefore, two bundles of wires with opposing currents, located between two copper plates 31, will oppose each other with electric fields and repel each other. Since the conductors are fixed motionless, only one electric field will be repelled among themselves and will be squeezed out along the corridor of copper plates from the flat beam 32 towards the round beam 33, similarly to engines with a deep groove / cm. p. 257, ibid. Example, FIGS. 3 and 6, around a round beam 33, a denser electric field 97 is formed compared to a flat beam 98, because a flat bundle of wires has a greater ability to dissipate the electric field. Therefore, the electric field of a plane beam cannot interact with the magnetic flux of the pole cores for two reasons, this is because of the distance from the poles and because of the weak electric field.

With a rapid change in the polarity of the current, the disappearing current in the conductors of the round section will cause a decrease in the magnetic field, the induction lines of which, crossing the conductors of the same section, located in a flat beam, will create, together with the decreasing current, powerful opposing magnetic pulses that will repel each other, thereby creating pushing the magnetic field toward the gap. The faster the polarity of the current in the circuit changes, the greater will be the magnetic pulses, which in turn will create a more powerful torque.

The operation of the electric machine in generator mode.

It is known that if the generator shaft is rotated in the same direction in which the engine worked, and while maintaining the same direction of the magnetic flux of the pole cores, then the current in the rotor windings will change its direction in the opposite direction. In the proposed scheme, with a parallel connection to the network of field windings and rotor windings, the reverse current of the rotor windings will lead to magnetization reversal of the pole cores, which can lead to disruption of the magnetic flux.

For more confident operation of the electric machine in generator mode, the output ends of the rotor winding must be interchanged, i.e. wire 88 is connected to terminal 20, and wire 92 is connected to terminal 21 / Fig. 2 and 8 /. In this case, the current in both field windings / OOB and BOB / will keep its direction and the magnetization reversal of the pole cores will not occur.

The current at the generator output / terminals 20 and 21 / can be adjusted by changing the current in the auxiliary excitation circuit. By decreasing or increasing the current in the field windings, the magnetic fluxes F1 and F2 (Fig. 2/) will increase or decrease, which in turn will reduce or increase the induced EMF in the rotor winding, as a result of this, the current at the output terminals 20 and 21 will increase or decrease .

The magnitude and density of current pulses at the output of the rotor circuit will depend on the number of active wires installed on the rotor and the number of pole cores installed on the bed. You can set an even and odd number of pole cores. For more powerful currents at the output, an even number of poles must be set, and to obtain a smoother current, an odd number of poles must be set. For one revolution of the rotor, sixteen positive pulses will occur, and each pulse will be summed from four pulses from each section, because four active sections pass simultaneously through four magnetic fluxes. If we assume that the generator rotor will make ten revolutions per second, then the current density will be 160 pulses per second / 10 · 16 = 160 /.

This gives the right to hope that this kind of electric machines will not have competitors and can be used to obtain a current of several hundred amperes, without requiring complex rectifier systems.

To put the electric machine into AC generator mode, it is necessary to break sixteen sections of the rotor winding into four groups, four sections in each group. Sections included in the first group / 1, 2, 3, 4 / and in the third group / 9, 10, 11, 12 / will leave the current direction in the windings in the same direction, and in sections included in the second group / 5, 6 , 7, 8 / and in the fourth / 13, 14, 15, 15 /, they will connect the current in the opposite direction, for which it is necessary to swap the output ends. In this case, the first and third sections will create a positive pulse, and the second and fourth sections will create a negative pulse, and at the generator output, positive (and negative) pulses will be summed into one of two pulses, because sections pass magnetic fluxes in pairs, the first with the third, and the second with the fourth.

An electric machine in the mode of an alternating current generator can be used to produce alternating current in a wide frequency range, which will depend mainly on the speed of rotation of the prime mover. If the engine rotates the generator at a speed of 10 rpm, then at the output of the generator it will be possible to obtain 40 Hz / 10 · 4 = 40 Hz /. If the engine rotates the generator at a speed of 15 rpm, then at the output of the generator it will be possible to obtain 60 Hz / 15 · 4 = 60 /, etc.

Claims (1)

An electric machine, including a bed, bed walls with field windings, a shaft with bearings, a rotor with armature windings, slip rings with ring holders, characterized in that all pole cores with field windings installed on the bed face the same poles to the rotor, in parallel the main field winding is connected to the auxiliary field winding, consisting of two sections connected in series, and by magnetic fluxes in the opposite direction, the sections are mounted on special rails groin made on the inner walls of the bed, concentric with the rotor shaft, the rotor is divided along the circumference into two equal parts, between which a copper gasket is installed and compressed by copper strips, several circular holes are made around the rotor circumference, closer to the rotor center, in the radial plane with round holes, the same number of slit-like holes are made in which the sections of the rotor winding are laid and secured, the sections are made in a U-shape and all are laid on one side of the rotor, they are pushed through with one end into a round hole, and another into a slit-like hole, on the opposite side of the rotor, the ends of the wires of each section are connected together in series, the ends of each section are also connected in series, and the common end and beginning of the rotor winding are connected to contact copper flat rings fixed on the shaft on the left and right sides of the rotor, which are in constant contact with stationary graphite flat rings held by compression flat springs mounted on the walls of the st Nina insulation ring fitted with the shaft, the rotor and the frame walls, graphite rings connected by wires to the common terminals of the rotor winding is connected in parallel with the field winding.

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