Square-cage rotor

FIELD: electricity.

SUBSTANCE: invention relates to a square-cage rotor for an asynchronous motor. The rotor contains a laminated pack (1) with groves (3), cage rings (5) of the first material moulded at end surfaces to the laminated pack and conductors (4) of the second material with higher conductivity than the first material, at that the conductors are placed in the grooves. Surface of the conductors (4) has a coating (8) of the coating material which through the first doped layer (2) of the second material and coating material borders with the second material of the conductors (4) and through the second doped layer (9) of the first material and coating material border with the first moulded material.

EFFECT: improvement of electrical efficiency for the square-cage rotor consisting of two materials.

25 cl, 6 dwg

 

The invention relates to a squirrel-cage rotor for an induction motor according to the restrictive part of paragraph 1 of the claims. In addition, the invention relates to a method of manufacturing a squirrel-cage rotor with signs of restrictive part of paragraph 10 of the claims.

Such a squirrel-cage rotor is known from DE 4308683 A1. This rotor comprises a sheet package with grooves, in which first vidvigayt korotkosheimi rods of copper. From the front side of the copper terminals are connected with each other using short rings. These short rings are manufactured through injection molding of aluminum. When casting short rings simultaneously pour the aluminum remaining in the grooves relative to the inserted copper rods residual cross-section, so that the short rings are connected and formed in the residual cross section of the injection molded parts of the rods.

Because copper compared to aluminum has a much higher electrical conductivity, thereby dramatically improving the efficiency of this motor compared to the induction motor, consisting entirely of die-cast aluminum material.

When running asynchronous e is extradigital and thereby also squirrel-cage rotor are dependent electrical losses inside the engine thermal cycles. Due to this thermal expansion in the rotor, which, based on the different thermal expansion coefficients of aluminum and copper is not homogeneous in such a squirrel-cage rotor. Due to this, copper rods may extend from die-cast aluminum material short rings, which eventually deteriorates the value of the transition electrical conductivity between short rings and rotor bars.

Similar efficiencies, as described above, is manufactured using the method of pressure die casting aluminum squirrel-cage rotors, can be implemented using die-cast copper rotors. Because it consists entirely of copper, not having the above-mentioned problems regarding the different coefficients of thermal expansion. However, the casting process of copper under pressure is very expensive and puts high demands on the tool for injection molding, because the copper for the process of molding is to be heated to temperatures above 1000°C. In contrast, with aluminum, you can work under pressure casting with much lower temperatures. In addition, made entirely of copper squirrel-cage rotor is heavier and thus more inertia relative to their starting the features of, what is known from DE 4308683 A1 squirrel-cage rotor, which has a short ring from aluminium.

The basis of the invention is to improve electrical efficiency consisting of aluminum and copper, made using the process of injection molding squirrel-cage rotor.

This problem is solved by using a squirrel-cage rotor for an induction motor, with squirrel-cage rotor contains:

- sheet package of the rotor with grooves,

- on the front side prelite sheet package of the rotor short rings of the first material and

- located in grooves of the conductors of the second material with a higher specific electrical conductivity than the first material,

while the conductors on its surface are covered with a covering material over the first doped layer of a second material and covering material borders with the second material of the conductors and through the second doped layer of the first material and covering material bordered with molded first material.

In addition, the problem is solved using the method of manufacturing a squirrel-cage rotor for an induction motor with the following stages of the method:

- laying of conductors from the second material in the grooves of the sheet is aceta rotor and

- casting on the front side short rings of the first material with a lower specific electrical conductivity than the conductivity of the second material sheet package of the rotor

when this conductor on its surface provided with a coating of opaque material so that there is the first doped layer of a second material and covering material between the second conductor material and the coating, while the coating material is made so that, in the casting method, the second doped layer of the first material and the covering material between the floor and cast the first material.

The basis of the invention is the understanding that due to this, it is possible to extremely improve the connection between the conductors and short rings, the first and second material form in the appropriate places intergranular connection. Korotkosheimi rods act on both face ends of the sheet pack of the rotor is molded short rings. According to the invention increase the strength of connection between the ends of the conductors and short rings is due to the fact that the conductors are covered so that there is an alloy, i.e. intergranular connection as between the coating and the conductor and between the floor and cast the first material short rings.

P is impactfully embodiments of the invention are specified in dependent claims.

Thus, in particular, the preferred embodiment of the invention, which is supplied by conductors grooves are filled by way of injection molding the first material, while the short rings are made by way of injection molding. Due to this korotkosheimi rods perfectly captured in the grooves. When korotkosheimi rods are located on directed radially to the inside bottom of the groove, due to hardening in the grooves of the melt occur starting rods on the basis of their lower compared to korotkosheimi rods conductivity provide improved starting characteristics of induction motor.

When heated during operation squirrel-cage rotor reached a temperature of about 150°C. due to this there is a greater thermal expansion in the filled first material zones of the grooves, in particular, when the first material is aluminum. Due to this, can disrupt the transition between the conductors and short rings, due to which there is deterioration in electrical conductivity in the transition zone between short rings and conductors. Compressed during molding to provide sealing in the axial direction of the sheet pack of the rotor can again EXT is sterile in the axial direction, when the connection between the conductors and molded short rings may not provide sufficient retention force.

By coating the conductors are connected to the maximum possible coupling forces with die-cast material. Accordingly, the connection between the conductors and short rings remains stable, despite the different coefficients of thermal expansion of the first and second material, also when the squirrel-cage rotor passes when working through a pronounced thermal cycles. At high speeds of rotation acting on the rotor of the centrifugal forces lead to the formation of partially large stresses in the connection between the conductor and the short ring. In addition, by doping an optimum transition electrical conductivity between the first and second material.

In a particularly preferred embodiment, the floor and the first doped layer is created by using electro-mechanical galvanization. In this first electrochemical route to the conductors deposited layer of coating material. Between the second material of the conductors and coating material occurs in this process the desired intergranular connection. When then put the first material, in particular, by using the process of injection molding, the coating on the wires melts and forms with pressurized melt is also intergranular connection, so there is a second doped layer.

Instead of electroplating possible other methods of coating, which also lead to the desired intergranular connections between the first material and the coating, and between the second material and the coating. Thus, the preferred embodiment of the invention in which the cover and the first doped layer is created using the method of thermal spraying, in particular flame spraying, arc spraying or laser deposition.

An alternative to this is an embodiment of the invention in which the cover and the first doped layer are created using cold spraying.

Another alternative is an embodiment of the invention in which the cover and the first doped layer is created by using gas spraying.

In all these ways, in particular when galvanization according to another preferred variant implementation of the invention, before application of the coating to remove the oxide layer with conductors through chemical pre-treatment of the conductors. The oxide layer has electrical insulating properties, so that by removing specified the CSO oxide layer is significantly reduced contact resistance between the first and second material.

In a particularly preferred embodiment, the first material is aluminum and the second material is copper. This gives rise to a hybrid squirrel-cage rotor, which on the basis of conductors made of copper has excellent electrical efficiency, it is much simpler to manufacture than the rotor in die-cast copper, and compared with it has a smaller mass and thus a smaller moment of inertia, because of its short rings are made of a relatively lightweight aluminum. In General, such a hybrid rotor has a better efficiency than the rotor in die-cast copper, which is made entirely of copper. For manufacturing such a squirrel-cage rotor first vidvigayt copper conductors in grooves sheet package of the rotor. Then, preferably using the method of pressure die casting aluminum fill the area of the grooves, which is not occupied by copper conductors. At the same time is made short ring from aluminium using the method of pressure casting.

Another preferred embodiment of the invention is characterized by the fact that the coating material is the first material. For example, in a hybrid rotor with copper rods and aluminum short rings on the surface max the x conductors apply a thin layer of aluminum. This is done by electroplating. In this coating process occurs alloy between aluminum and copper conductors. Then pressurized aluminum mass injected into the grooves at the same time cast short rings. This aluminum coating on the surface of conductors melts and forms with the aluminum melt intergranular connection. This ultimately form the second doped layer. In particular, in the area of the ends of the copper rods that protrude from the sheet pack of the rotor in short rings, there is an extremely stable connection between the two materials, so that the relative strength of thermal cycles and occurs when the centrifugal force increases. When this occurs almost perfect electrical and mechanical connection between the short rings of aluminum and copper rods.

In the casting process can produce significant chemical reaction between the supplied coating conductors and melt. To prevent too much of the demolition of the conductors due to being in contact with the conductors of the first material melt in a preferred embodiment of the invention, the coating doped layers can be located exclusively the speakers on sheet package of the rotor and are included in short rings of the end areas of the conductors. These end zones are critical connection between the conductors and short rings. Accordingly, it is particularly important strong crystalline compound. First of all, in this end area of each conductor transition electrical conductivity is of particular importance, since the current passes from the conductor in shorting sleeve. In contrast, manufactured through injection molding rotor strong crystalline compound conductors in areas within the grooves need less, because there should no passage of current from the first to the second material, respectively, and Vice versa.

However, simpler to perform, in particular, in the coating by electroplating, is the embodiment of the invention, in which the coating doped layers completely surrounding the conductors.

However, possible and preferable embodiment of the invention, in which the surface of conductors, which is inside the grooves facing the injection molded first material has no coverage. This prevents the demolition material addressed to melt the surface of the conductors. Instead of missing coating on a given surface may be provided resistant to the melt layer. So, for example, can be the beginning of a fully electroplated conductors and thereby be covered with coating material, which leads to the formation of the desired doped layers. You can then exclusively found on the surface of conductors, which is inside the grooves facing the injection molded first material to provide the relevant proof to melt pestiviruses layer.

The connection between the conductors and short rings in another preferred embodiment, the invention further reinforce the fact that the conductors on both ends protruding from the sheet pack of the rotor and is a member of the short ring end zone equipped with means for creating geometric circuit between conductors and molded short rings. These funds geometric circuit in end zones of conductors further strengthened the connection between the conductors and short rings. Speakers at the ends of the conductors are pulled in the axial direction by means of the geometric circuit with short rings. Thus, the conductors, depending on temperature and coefficient of thermal expansion of the conductors and short rings are stressed in tension or compression. It is necessary to perform a squirrel-cage rotors so that the load always remains in the elastic range. Due to the applied geometric means is mikania prevents the shift of conductors within a short rings or pulling wires from short rings, what prevents a gap junction between the two materials. As geometric means of the circuit can be used, for example, through holes in end zones of conductors that are filled with the melt during the casting process. Instead of the through holes can also be used grooves in end zone, narrowing of the conductors inside the end zones, notch, roll end zones, virtualroot conductors in end zones or splitting conductors in end zones.

On the basis of one of the above embodiments squirrel-cage rotor according to the invention, by using the corresponding stator simple way to implement an asynchronous motor, which is also at high thermal loads and high speeds of rotation always has good electrical efficiency and is extremely stable.

Below is a more detailed description and explanation of the invention on the basis of examples with reference to the accompanying drawings, which depict:

figure 1 - hybrid running squirrel-cage rotor induction motor;

figure 2 - section a squirrel-cage rotor;

figure 3 is a section along the surface of the partition provided between the coated conductor and compression molded by perimetrium;

figure 4 - section of another variant of execution of the squirrel-cage rotor hybrid design tools with geometric circuit conductors in the zone of the short rings;

5 is a cut grooves with conductors that are free from coating surface; and

6 is an asynchronous motor with one of the embodiments squirrel-cage rotor.

Figure 1 shows the implementation of the short-circuited rotor of the hybrid design of asynchronous motor. Shows the sheet package 1 of the rotor of the asynchronous motor, which is mounted in the hot condition on the shaft 11. In the manufacture of squirrel-cage rotor first vidvigayt conductors 4, which are preferably made of copper in the grooves 3 of the sheet package 1 of the rotor. You can see that the cross-section of conductors 4 is less than the cross-sectional area of the grooves 3. Thus, after installation made in the form of copper rods conductors 4 remains free of residual cross-section grooves 3.

For the manufacture of squirrel-cage rotor used in the next stage of the method of injection molding. In this way made short ring on the end faces are in contact with copper rods, and at the same time filled with melt even the free spaces of the grooves 3. After solidification of the aluminum melt inside grooves occur in the remaining residual cross-section part 6 aluminum rods that secure the copper rods in their position and immediately adjacent to them. These parts 6 aluminum rods can preferably also be used as a starting rod induction motor, because they have a lower electrical conductivity as compared with copper conductors. In particular, when part 6 aluminum rods are, unlike shown in figure 1, in a radially outward directed to the area of the grooves, they have a positive influence on the course of change of torque of the asynchronous motor.

Due to the hybrid structure, i.e. through the use of conductors 4 of copper and short rings made of aluminum, it is possible to make squirrel-cage rotor with a particularly good electrical efficiency. This is due, on the one hand, the good conductivity of copper and, on the other hand, a relatively low weight made of aluminum short ring, leading, respectively, to the relatively small mass of inertia.

Figure 2 shows a sectional squirrel-cage rotor, in which you can see along with the sheet package 1 rotor, surrounded by aluminum RA is the water and laid in the grooves 3 conductors 4. On their face ends of these conductors 4 are immersed in is made of die-cast aluminum short ring 5. Due to temperature fluctuations, which is experiencing a short-circuited rotor during engine operation, may occur, particularly in end zones of the branch wires 4 from short rings 5. This is due, in particular, the different coefficients of thermal expansion of the used materials are copper and aluminum. Therefore, the hybrid rotor is particularly important to ensure a stable connection between the two materials, copper and aluminum, in particular, in the area of short rings 5.

Figure 3 shows a section along the surface of the partition provided between the coated conductor 4 and the injection molded first material parts 6 aluminum rods. This edge surface occurs due to the performance of the coating according to the invention, the conductor 4 before the process of injection molding. In this case, the first material is aluminum and the second material of the conductor 4, copper. Copper conductors are fitted, for example, using the process of galvanization coating 8. Before that, the conductors 4 are treated chemically to remove the layer of copper oxide from the surface, which causes deterioration of the electrical conductivity. Then the conductors 4 is Agregat in the electroplating bath, where to apply suitable coating material. However this may be, for example, the first material, i.e. aluminum. Due to this method of coating between the coating 8 and the copper conductor 4 occurs a transition zone, which in the following is called the first alloyed layer 2. Inside the first doped layer 2 there is intergranular structure, which provides an extremely strong connection cover 8 with copper conductors 4.

In the further course of the method are covered conductors 4, which is pushed into the grooves 3 sheet pack 1 rotor, is subjected to the process of pressure die casting aluminum. As soon as the melt reaches the conductors 4, due to the heat melts a portion of zone 8 of the coating on the surface. Formed by the second doped layer 9, which occurs intergranular phase of the coating material and pressurized melt aluminum. This ultimately leads to the fact that part 6 aluminum rods extremely strongly linked to area 8 of the coating. This prevents the separation of the pressurized molten aluminum from the conductors 4 with the passage of thermal cycles squirrel-cage rotor or at extremely high speeds of rotation.

Figure 4 shows in section another implementation of the short-circuited rotor hybrid is the first design with conductors 4 with means 7 geometric closures in the area short of the rings 5. Means 7 geometric circuit conductors 4 made in the form of through holes. When the exposure is supplied by conductors 4 sheet package method of pressure die casting aluminum tools 7 geometric closures are filled with molten aluminum. This leads to the fact that the connection with geometric closure further ensures that the conductors 4 during thermal cycles remain within the connection zone short of the rings 5. Thus, it is shown means 7 geometric circuit also support the action of the coating according to the invention, that prevents the ejection end all conductors of injection molded short rings 5.

Figure 5 shows the cut grooves 3 conductors 4, which are free from coating the surface 12. Shown here, the squirrel-cage rotor is a hybrid rotor with 6 parts of aluminum rods, which act as the starting rod. First, the grooves 3 are investing conductors 4, which are directly adjacent to directed radially inward to the bottom of the groove. In the process of pressure die casting aluminum filled aluminum melt remaining free of residual cross-section, while the residual cross-section is directed radially outward zone. Thus, on the one hundred and the ons, it is ensured that only the surface of the conductor 4 is in contact with pressurized aluminum material. On the other hand, part 6 aluminum rods lying radially on the outside, which results in made with copper rods as guides squirrel-cage rotor on the basis of lesser conductivity of aluminum for improved starting characteristics. In addition, lying outside the actuator rods press the conductors 4 to the bottom of the groove so that the conductors 4 can be fixed very well in sheet package of the rotor.

Depending on the coating material during injection molding can be a considerable demolition material provided with a coating of conductors 4. To prevent this, converted to part 6 aluminum rods side conductors 4 are uncoated. Therefore, the conductors 4 are laid in the grooves 3 area not exposed to the specified demolition material. Just protruding from the sheet pack of the rotor end zone conductors 4 are completely covered with the purpose of creating a desired strong connection with short rings. In contrast, intergranular connection between the conductor 4 and 6 parts of aluminum rods in the area of the grooves is not required.

Figure 6 shows the induction motor 10 with squirrel-cage rotor is under one of the above embodiments. This induction motor is characterized by high electrical efficiency and much more simple to manufacture and has a lower cost compared with asynchronous motor with die-cast copper rotor. Also shown induction motor 10 is compared with the induction motor with die-cast copper rotor improved dynamic performance as a hybrid rotor shown induction motor has a much smaller moment of inertia.

1. Squirrel-cage rotor for an induction motor, with squirrel-cage rotor includes:
- sheet package (1) rotor with grooves (3),
- on the front side prelite sheet package of the rotor short ring (5) from the first material, and
- located in grooves of the conductors (4) of the second material with a higher specific electrical conductivity than the first material,
while the conductors (4) on its surface are coated (8) of the coating material through the first doped layer (2) from the second material and covering material borders with the second material of the conductors (4) and through the second doped layer (9) of the first material and covering material bordered with molded first material, and partyinternal is aluminum, and the second material is copper,
characterized in that the coating (8) and the first doped layer (2) formed by electrochemical plating.

2. Squirrel-cage rotor according to claim 1, in which the coating (8) is deposited on the conductors (4).

3. Squirrel-cage rotor according to claim 1 or 2, which is supplied by the conductors (4) of the grooves (3) are filled by way of injection molding the first material, with the method of injection molding are short rings.

4. Squirrel-cage rotor according to claim 3, in which the coating material is the first material.

5. Squirrel-cage rotor according to claim 3, in which the coating (8) and doped layers (2, 9) are located exclusively on the speakers of the sheet package (1) of the rotor and are included in short rings (5) of the leaf areas of the conductors (4).

6. Squirrel-cage rotor according to claim 3, in which the coating (8) and doped layers (2, 9) completely surround the conductors (4).

7. Squirrel-cage rotor according to claim 3, in which the surface of the conductors (4), within which grooves facing the injection molded first material has no cover (8).

8. Squirrel-cage rotor according to claim 3, in which the conductors (4) on both ends protruding from the sheet pack of the rotor and is a member of the short ring (5) of the end zone equipped with means (7) geometric circuit d is I create a geometric circuit between the conductors (4) and cast short rings (5).

9. Induction motor (10)containing a stator with stator windings and a squirrel-cage rotor and squirrel-cage rotor includes:
- sheet package (1) rotor with grooves (3),
- on the front side prelite sheet package of the rotor short ring (5) from the first material and
- located in grooves of the conductors (4) of the second material with a higher specific electrical conductivity than the first material,
while the conductors (4) on its surface are coated (8) of the coating material through the first doped layer (2) from the second material and covering material borders with the second material of the conductors (4) and through the second doped layer (9) of the first material and covering material bordered with molded first material and the first material is aluminum and the second material is copper,
characterized in that the coating (8) and the first doped layer (2) formed by electrochemical plating.

10. Induction motor (10) according to claim 9, in which the coating (8) is deposited on the conductors (4).

11. Induction motor (10) according to claim 9 or 10, which is supplied by the conductors (4) of the grooves (3) are filled by way of injection molding the first material, with the method of injection molding made korotkozamknutyh.

12. Induction motor (10) according to claim 11, in which the coating material is the first material.

13. Induction motor (10) according to claim 11, in which the coating (8) and doped layers (2, 9) are located exclusively on the speakers of the sheet package (1) of the rotor and are included in short rings (5) of the leaf areas of the conductors (4).

14. Induction motor (10) according to claim 11, in which the coating (8) and doped layers (2, 9) completely surround the conductors (4).

15. Induction motor (10) according to claim 11, in which the surface of the conductors (4), within which grooves facing the injection molded first material has no cover (8).

16. Induction motor (10) according to claim 11, in which the conductors (4) on both ends protruding from the sheet pack of the rotor and is a member of the short ring (5) of the end zone equipped with means (7) geometric circuit for creating geometric circuit between the conductors (4) and cast short rings (5).

17. A method of manufacturing a squirrel-cage rotor for an induction motor with the following stages of the method:
- the laying of the conductors (4) of the second material into the grooves (3) sheet pack (1) rotor and
the casting on the front side short rings (5) from the first material with a lower specific electrical energy is achieved by conduction, than the conductivity of the second material sheet package of the rotor
while the conductors (4) on their surface provided with a coating (8) of the coating material so that there is the first doped layer (2) from the second material and covering material between the second material of the conductors (4) and cover (8), while the covering material is made so that, in the casting method, the second doped layer (9) of the first material and the covering material between the cover (8) and cast the first material and the first material can be applied to aluminum and the second material is copper,
characterized in that the coating (8) and the first doped layer (2) create by electrochemical plating.

18. The method according to 17, in which the coating (8) on the conductors (4) napravlyayut in the casting process.

19. The method according to 17 or 18, which is supplied by the conductors (4) of the groove (3) is filled using the method of injection molding the first material.

20. The method according to claim 19, in which the coating material used for the first material.

21. The method according to claim 19, in which the coating (8) and the first alloyed layer (2) is provided solely protruding from the sheet pack of the rotor and are included in short rings (5) end-zone conductor (4).

22. The method according to claim 19, in which the conductors (4) are fully provided with a coating (8) is first alloyed layer (2).

23. The method according to claim 19, in which the surface of the conductors (4), within which grooves facing the injection molded first material is not provided with a coating (8).

24. The method according to claim 19, in which between the conductors (4) and cast short rings (5) create a positive locking in both projecting from the sheet package (1) of the rotor and are included in short rings (5) of the leaf areas of the conductors (4).

25. The method according to claim 19, in which before coating to remove the oxide layer with conductors (4) through chemical pre-treatment of the conductors (4).



 

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3 cl

FIELD: electricity.

SUBSTANCE: invention is related to electrical engineering, in particular, to methods of operation and diagnostics of electrical machines, mainly generators of power plants. Technical result ensures effective elimination of accelerated wear processes for stator elements attachment fitting without essential limitation of reactive power transmitted by the electrical machine to the network. In order to attain the above technical result parameters of vibro-acoustic oscillations of the electrical machine structural components are measured by means of well-known devices. Against measured data accelerated wear process is detected in stator elements attachment fitting in result of vibroimpulsive interaction of elements in defect units. Electric parameters such as excitation current and reactive load are measured during operation mode of the electrical machine. Reduction of wear processes in the attachment fitting is ensured by change of excitation current of the machine. Change of excitation current is made till vibroimpulsive interaction of elements in defect units is stopped. Thereafter current excitation value is recovered close to the initial value so that reactive power of the generator complies with requirements of the power system operator. The suggested method is based on use of non-linear events in vibroimpulsive systems found in attachment fitting of stator end windings so that frictional force acting in attachments fittings in conditions of rest state is always bigger than sliding friction.

EFFECT: invention allows recovering excitation current to the initial value after stoppage of accelerated wear processes without their renewal.

2 cl, 1 dwg

FIELD: electricity.

SUBSTANCE: control apparatus includes a controlled stabilised direct current source (1), a switch (2), a controlled resistor (3), a first amplifier (4), a second amplifier (5), a comparator (6), an inverter (7), a first AND circuit (8), a multivibrator (9), a second AND circuit (10), a first counter (11), a second counter (12), a first register (13), a second register (14), a computer (15), a resistance metre (16), the inspected electrical machine (17), an angular position sensor (18), a reducing gear (19), an electric motor (20), a control unit (21), consisting of the following elements: a T flip-flop (22), a third AND circuit (23), a relay (24) with a coil (25) and a normally closed contact (26), a second power supply (27) and a START toggle switch (28).

EFFECT: high reliability and accuracy of controlling the bearing assembly and the electrical machine as a whole.

2 cl, 2 dwg

FIELD: electricity.

SUBSTANCE: harmonising method of magnetic conductors or rotor and armature in DEM-G, which are made using magnetic conductors of armature with brush-collector assembly of direct current machines and stator of alternating current machines, which is used as external rotor, is characterised by the fact that initial existing air gap δI is determined between rotor and armature by the following formula: δI=(Dr-Da)/2, where Dr - rotor inner diameter, Da - armature outer diameter; then, necessary final air gap δkp is calculated by the following formula: δkp(0,27÷0,33)106ABδoτxd*,, where A - linear load, Bδo≈0.95 Bδ nom - maximum induction in air gap at idle stroke and nominal voltage, τ - polar pitch, xd* - synchronous inductive resistance along longitudinal axis, difference Δ = δI - δkp={[(Dr-Da)/2]-δkp} is found between initial air gap δI and design end air gap δkp; then, cylindrical surface of armature is increased along outside circumference by covering it with one or more layers of electrical steel plates and by bringing total thickness of layers of electrical steel plates to the value that is equal to calculated difference Δ, thus providing expedient end air gap δK≈δkp between rotor and armature from the point of view of power. Electrical steel on armature surface is fixed by spot welding.

EFFECT: increasing energy indicator ηcosφ of two-dimensional electric machines.

2 cl, 3 dwg

FIELD: electricity.

SUBSTANCE: method is carried out by measurement of current values in two points of its shorting ring spaced relative to each other by the value of a pole division of the induction motor or multiple to it, for this purpose on the shorted ring of the rotor in the specified points there are two current sensors installed. Values of currents flowing in the shorting ring of the rotor certify availability or absence of motor damages.

EFFECT: provision of the possibility for continuous simultaneous diagnostics of electric and mechanical damages of an induction motor with a short-circuit rotor during motor operation.

FIELD: electricity.

SUBSTANCE: laser device to measure an air gap of an electric machine, comprising a stator and a rotor, includes a laser, having two faces of a resonator to radiate output light, the light from the first face of the resonator is scattered on the surface of the electric machine rotor and arrives back into the laser, a module to control optical frequency of the laser, connected to the laser and changing its optical working frequency, a module of optical detection sensitive to output light from the second face of the resonator. Intensity of the output light is related to the distance to the rotor due to interference in the laser between the scattered light from the rotor and the light in the laser. Also the device comprises a module of synchronisation with a rotor, which is connected to the module of distance measurement, and a module of phase accumulation, which is connected to the module of synchronisation and module of distance measurement and performs phase accumulation of measured data.

EFFECT: invention provides for reduced error of measurement with availability of high resolution of measured data.

1 dwg

FIELD: electricity.

SUBSTANCE: rotating machine contains at least one rotating component and least one fixed component located so that between parts of at least such elements only certain gap is created having measured radial dimension and measured magnetic flux which is generated in the gap at least partially due to relative movement of fixed and rotating components. According to this invention, gap measurement unit contains at least one device for gap size measuring which device is configured with possibility to determine capacity change using proximity determination probe and at least one device for measuring gap magnetic flux configured with possibility to determine voltage change by means of magnetic flux measuring, where at least one device for gap size measuring and one device for gap magnetic flux measuring are synchronised so that input signal of gap size and input signal of gap magnetic flux are generated virtually simultaneously.

EFFECT: providing operative and effective measurement of rotating machines working gap and magnetic flux with simultaneous support of time and place synchronisation of specified parameters measurement, lowering capital, mounting and operational costs, improvement of reliability of rotating machines such as generators and turbine generators, and reducing their emergency outages.

9 cl, 4 dwg

FIELD: electricity.

SUBSTANCE: additional electromagnetic actuator connects windings of an electric motor when resistance to leakage currents drops below the specified level to the specified capacitors and disconnects them after achievement of the required level of resistance. The circuit from V, R, VD is required to indicate drying, a SB1 button makes it possible to forcedly inspect resistance of insulation, and when its value is low, drying of windings is started.

EFFECT: increased resource of an electric motor and reduction of its outage time due to provision of insulation resistance monitoring and timely drying of electric motor windings due to using of a differential transformer of zero sequence current in a proposed device, made with additional coils to increase sensitivity during registration of leakage currents in process of drying, and also an amplifier, an additional electromagnetic actuator and capacitors.

1 dwg

FIELD: electricity.

SUBSTANCE: system (300) of mechanism monitoring includes at least one movable element, comprises at least one sensor (372, 374) to generate at least one signal of measured speed of the movable element, and at least one processor (382) connected along a data transfer system with the sensor. At least one processor is configured to generate multiple signals of measured speed with time markers, at least for one movable element and is additionally configured to determine priorities of multiple measured speed signals with time markers as a function of at least one previously determined time value.

EFFECT: provision of simultaneous recording, transfer or processing of components speed and vibration data.

10 cl, 6 dwg

FIELD: electricity.

SUBSTANCE: when implementing the proposed method, temperature sensor is placed into hollow threaded bolt which is screwed into the seat of eye-bolt of electric motor housing; at that, contact points of hollow metal bolt with housing of electric motor and temperature sensor are coated with heat-conducting paste; heating temperature of stator core is measured; the value of obtained signal is amplified; at that, quantitative connection between heating temperatures of core and winding is considered by determining the value of temperature coefficient Kt=Tw/Ts, where Tw - winding temperature, Ts - stator temperature, and obtained value of stator temperature signal is increased by 1.4 - 1.7 times; actual value of heating temperature signal of stator winding is obtained and supplied to input of signal unit; the obtained signal is compared to signal of setting device by means of which the required threshold of actuation of signal unit is set, which considers the value of maximum allowable overheat temperature of winding of protected electric motor for this insulation class, the required temperature reserve is created; indicator-light emitting diode is connected to the first output of signal unit; acoustic wave generator-buzzer is connected to the other output of signal unit; and the third output of signal unit is connected to tripping device, and by means of them, in case of emergency situation due to overheat of windings of protected electric motor the light signal is supplied and at the specified time interval the acoustic signal is supplied, which indicate emergency situation occurrence, or the signal for cut-off of protected electric motor with magnetic starter is supplied from supply mains.

EFFECT: simplifying the method, improving heating control accuracy of electric motors and protection reliability of windings of electric motors against overheat in operating conditions; method provides the possibility of independent use and excluding the interference with the design of electric motor for installation or replacement of failed temperature sensors built in front parts of stator windings of electric motor.

1 dwg

FIELD: technological processes.

SUBSTANCE: invention relates to the field of metal processing, in particular to portable plants for mechanical treatment of cylindrical surfaces of bulky items, and namely to treatment of thermal and nuclear power plants (NPP) turbine rotors. Method for repair of turbine rotor shaft in area of its operation includes installation of rotor onto roller supports, rotating the rotor and mechanical treatment of cylindrical surfaces of shaft. Rotor is installed on rotor supports arranged in lower part of turbine body, at the angle of 4-8° to rotary axial thrust arranged in lower part of turbine body, and it is rotated by hydraulic drive.

EFFECT: provides for purity of treated surfaces of large diametre cylindrical parts in conditions of power plant.

1 dwg

FIELD: electrical engineering; in-service checkup of electrical machine insulation at its end connections.

SUBSTANCE: proposed device designed to detect faults in insulation near end portions beyond sections covered with semiconductor materials, insulation of end portion head boxes, insulation of output and interconnecting buses, insulation of binding rings and winding holders has high-voltage supply and insulating rod with test electrode. Novelty is that high-voltage supply has generator connected at its output to step-up transformer whose secondary winding leads are connected to rectifier-multiplier one of whose leads is connected to high-voltage lead of high-voltage power supply and other lead, to ground through microammeter. Rod-mounted test electrode is connected to high-voltage lead of high-voltage power supply.

EFFECT: enhanced reliability of ground detection without destructive actions; facilitated handling of this portable device.

1 cl, 1 dwg

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