RU2361349C1 - Stator winding installation and impregnation method to be used in asynchronous auxiliary motors - Google Patents

Abstract

FIELD: electric engineering.

SUBSTANCE: invention relates to electric engineering, and particularly, to devices intended for impregnating windings of driving motors in railway vehicles. According to the invention, the impregnation plant for asynchronous auxiliary motor stator windings includes the following: impregnation tank and storage tank for impregnating agent. Both tanks are interconnected by a pipeline. There is a filter in the pipeline to decontaminate impregnating agent. Both tanks are provided with heating elements, level metres, thermal sensors, pressure transducers and connected to vacuum system. The impregnation tank is equipped with U-sonic system, while storage tank is connected to the compressed air system. According to the stator winding impregnation method to be implemented on the above-mentioned plant, the stator winding is immersed into impregnation tank, heated to 120 - 140°C and cured until water vapours are removed from winding. Then, stator winding is cooled to 60-70°C, and pre-heated impregnating agent is supplied to impregnation tank. The impregnating liquid is subject to cavitation by means of U-sonic system and bubbling is generated due to compressed air supply. As a result, the shock waves clean the stator windings. The decontaminated impregnating agent is pumped into storage tank and vacuumed. Clean impregnating agent is again supplied to the tank for impregnation, vacuum system is actuated and air is removed from the tank and impregnating agent. Finally, U-sonic system is switched on, cavitation is created and deep impregnation of stator winding is conducted by applying shock waves.

EFFECT: increased rate of items saturation with impregnating agent by creating conditions of more effective gas and vapours removal from item surface and inter-turn space and from impregnating agents.

4 cl, 2 dwg

Description

The invention relates to a device for impregnation of the windings of traction motors in railway transport.

Static data on the reliability of components and parts of equipment of electric locomotives under operating conditions show that a large proportion of failures occur in electric cars.

It has been established that more than 75% of damage to induction motors is caused by breakdown of the insulation of stator windings due to a decrease in its dielectric strength. Known methods that improve the quality of impregnation of the stator windings.

For example, the method of impregnation and drying of electrical products and installation for its implementation (RF patent No. 2128392, IPC Н02К 15/12, application 16.12.1997). The essence of the method of impregnation and drying of electrical products is that they carry out pre-heating of products, their impregnation with an appropriate composition and subsequent drying. At the stage of preliminary current heating, products connected in series using automatically connected contact groups are connected to a current stabilizer and periodically pass current with a given current and pause time, and the heating of the winding from the inside with a cold metal part is achieved.

When passing current, the products are heated and actively monitored in the preheating zone for breaks, short circuits, and short circuits to the case, and during a pause, they monitor the temperature of the products at the position before impregnation, which is stored until the next measurement cycle and based on which the cycle is controlled pre-heating with the ability to smoothly and quickly set the desired temperature of the products.

On its basis, a signal is formed to permit the movement of the conveyor and the movement of the product into the impregnation zone.

After impregnation, the product is subjected to a drying operation, which includes direct heating of the metal part of the product with electric heating elements and simultaneous drying with a stream of hot air circulating through a closed duct, while the air temperature, which is the same at all points of the drying chamber, is supported by a seven-power power controller with the possibility of its operational change .

In addition, a special exhaust ventilation channel ensures the optimal concentration of vapor of the impregnating composition in the drying chamber.

The installation for impregnation and drying of electrical products, including a pre-heating unit, an impregnation unit and a drying chamber, is characterized in that the pre-heating unit has automatically connected contact groups for sequential connection and heating of products with a stabilized current, and the impregnation unit contains a hermetically sealed tank with a flexible transparent indicator tube connected to the impregnation bath tube for supplying the composition to the bath and a tube to maintain a given level in the bath, while The other is equipped with a transition tube with a thread and a level scale, an adjusting screw and a tip, and a measuring ruler is installed in the bath.

The specified method has the following disadvantages: because of the complex structure of the frontal parts, the impregnation of the windings of the traction electric motors is not sufficiently ensured and the impregnation time is more than doubled to achieve high-quality impregnation.

The invention is known "Method for the impregnation and drying of electrical products (RF patent No. 2138899, IPC Н02К 15/12, application filing date 06/20/1997).

The objective of the invention is to develop a method of impregnation and drying of products, which allows to increase the degree of saturation of their impregnating material by creating conditions that allow more efficient to remove gases and vapors from the surface and inter-turn space of products.

The proposed method provides for impregnation of the impregnating material and products in isolation from each other, to degass in a vacuum-pulse mode, and then carry out the impregnation and then drying in the same mode.

Pulse evacuation is carried out at a residual pressure of 0.1-13.3 kPa and the time it reaches 0.07-1.0 s. The above modes on existing equipment ensure the optimal flow of all stages of the technological process and allow to achieve 100% impregnation of electrical products with high diffusion resistance, such as magnetic cores, electric motors and transformers with a dense winding from wires of small cross section.

The disadvantage of this method is the low productivity of impregnation of the stator windings of asynchronous auxiliary machines.

The closest in technical essence to the proposed device is the “Ultrasonic impregnation device” according to the patent of the Russian Federation No. 2224649 (IPC V29V 15/10, application filing date 02.17.2003).

The essence of the proposed technical solution lies in the fact that in the known device for ultrasonic impregnation of a filler with a binder, including a bath with a binder, pressure rollers for moving the filler along the bottom of the bath, an ultrasonic oscillatory system consisting of a transducer of electrical vibrations into ultrasonic, a mechanical vibration concentrator and a working one a tool placed above the surface of the bath with a binder so that the working tool is immersed in the binder.

The working tool of the oscillatory system is made in the form of a plate with rounded edges, having a curved radiating working surface.

The transverse size of the working tool is set from the condition of ensuring a single-layer placement of the filler along the width of the working tool during the impregnation process.

The longitudinal size of the plate is selected from the condition of ensuring the desired degree of impregnation at a given speed of drawing the filler through the bath with a binder.

An ultrasonic vibrating system is placed above the bath with a binder so that the acoustic axis of the oscillating system is at an angle to the surface of the binder in the bath.

Part of the working tool is located above the surface of the binder, and the pinch rollers are positioned so that during the process of drawing the filler along the surface of the working tool, the filler is in mechanical contact with the radiating surface of the ultrasonic vibrating system.

The lower wall of the bath at the location of the working tool of the oscillatory system above it is performed at an angle to the surface of the binder to the bath, perpendicular to the acoustic axis of the oscillatory system.

The distance from the surface of the working tool to the bottom is set equal to half the wavelength of ultrasonic vibrations in the binder at the working frequency of the oscillating system.

The prototype has the following disadvantages: low productivity and the need to rotate the stators, which complicates the design and increases the process time.

The aim of the proposed technical solution is to create conditions that facilitate the penetration of the impregnating substance into the pores of the winding and help to reduce the number of gaseous inclusions in the stator winding during impregnation, thereby improving the quality of impregnation and increasing the insulation resistance of the stator winding.

The goal is achieved by the fact that the proposed installation consists of a container with an impregnating substance and an ultrasonic system, a container for storing an impregnating substance, which is connected by a pipe to a container for impregnating through a filter, both containers equipped with heating elements, level gauges, temperature sensors, pressure sensors and connected to a vacuum system. The impregnation tank is equipped with ultrasonic emitters, and the storage tank is connected to a compressed air system.

Ultrasonic emitters are mounted opposite in the upper and lower parts of the stator winding evenly around the circumference.

A method of impregnating the windings of the stators of asynchronous auxiliary motors involves heating the impregnating substance and creating ultrasonic vibrations in the impregnation vessel.

The difference is that after installing the stator winding of the motor in the impregnation tank, it is heated to a temperature of 120-140 ° C to remove water vapor from the winding, then it is cooled to 60-70 ° C, after which the impregnation tank is filled with an impregnating substance, pre-heated in storage tanks.

Then, ultrasonic emitters are turned on and cavitation is created in the impregnating substance and air bubbled, as a result of which shock waves are generated, which clean the stator winding from dirt.

After cleaning, the impregnating substance is pumped through the filter into the storage tank, vacuum it, clean the air and pump the impregnating substance into the impregnation tank. After filling the impregnation tank, cavitation is created using ultrasonic vibrations in the impregnating substance, providing shock impregnation of the stator winding with the help of shock waves.

The essence of the invention is illustrated by schemes:

Figure 1 presents the General installation diagram of the impregnation of the stator winding of the asynchronous auxiliary electric motors;

Figure 2 presents the layout of ultrasonic emitters.

The impregnation installation of the stator windings (Figure 1) contains an impregnation tank 4, a storage tank 11, which are interconnected by a pipeline, the pipeline has a filter 10 for cleaning impregnating substance from dirt.

Capacity 4 and capacity 11 are equipped with sensors 5 for measuring pressure, level gauges 6 for level control in tanks 4 and 11, temperature sensors 7 for temperature monitoring in tanks 4 and 11, heating elements 8 for drying the stator windings 15 in tank 4 and heating impregnation substances in the tank 11, a vacuum pump 9 to create a vacuum in the tanks 4 and 11.

In addition, the tank 4 is equipped with an ultrasonic system, which includes an ultrasonic generator 1, a commutator 2 and ultrasonic emitters 3 for creating cavitation in the impregnating substance, and the tank 11 has a compressed air supply 12 for creating a bubbling in the tank 4.

The entire process of impregnation of the stator windings is controlled by a discrete-analog control line 14.

Installation works as follows.

The stator winding 15 of the asynchronous auxiliary electric motor is installed in the impregnation tank 4 on a special stand.

Then, the heating elements 8 are turned on, the stator winding 15 is heated to a temperature of 120-140 ° C and the stator winding is dried to remove water vapor, which then enters the exhaust ventilation 13.

According to standards, this period is 10 hours.

After drying, the stator winding 15 is checked for insulation resistance.

In the next step, after cooling of the stator winding 15 to a temperature of 60-70 ° C, a preheated impregnating substance is supplied through the pipeline to a temperature of 45-50 ° C from the storage tank 11 to a predetermined level and temperature. Level control is carried out using a level gauge 6, temperature - using a temperature sensor 7.

To create cavitation include ultrasonic emitters 3 and through the inlet 12, compressed air is supplied to create a bubbling.

Pulsating bubbles (a large number) formed due to the bubbling, filled with air, making complex movements, merge with each other, forming large bubbles, which then collapse, forming micro-shock waves and microflows in the impregnating substance. In this case, alternating regions of local high and low pressures are formed, i.e. high compression zones and rarefaction zones are created.

In the discharged zone, the hydrostatic pressure decreases to such an extent that the forces acting on the liquid molecules become greater than the forces of intermolecular adhesion.

As a result of a sharp change in hydrostatic equilibrium, the impregnating substance “breaks”, forming numerous tiny air bubbles. At the next moment, when a period of high pressure begins in the liquid, the previously formed bubbles collapse.

The process of collapse of the bubbles is accompanied by the formation of shock waves with a very large local instantaneous pressure reaching several hundred atmospheres.

When creating bubbling, the process of collapse of the bubbles and the cleaning process of the stator winding 15 is faster.

At the end of the washing of the stator winding 15, the washing substance is pumped into the container 11, having previously cleaned the impregnating substance from dirt using a filter 10.

Next, the container 4 is again filled with the impregnating substance to a predetermined level, the vacuum pump 9 is turned on, and air is removed from the container 4 and the impregnating substance, the ultrasound system is turned on, and due to the ultrasonic emitters 3, cavitation occurs in the impregnating substance.

Cavitation bubbles, the pulsation of which leads to the occurrence of shock waves, produce micro-shock penetration into the stator winding 15, impregnate the stator winding 15 to a greater depth. Moreover, the ultrasonic wave, having passed the stator winding 15, collides with the wall of the vessel 4, is reflected and once again ensures the passage of the reflected shock wave, which allows to increase the depth of impregnation of the stator winding 15. In the work (“Physical basis of ultrasonic technology”, edited by L.D. Rosenberg, Moscow: Nauka, 1970, p. 187) the optimal range of process efficiency and safety has been determined:

- to remove contaminants with high adhesion to the surface - 18-22 kHz;

- for cleaning from contaminants weakly associated with the cleaned surface (fatty and mechanical) - 40-44 kHz.

Impregnation time according to the standards of 10-15 minutes.

Upon completion of ultrasonic treatment, the impregnating substance is discharged into the container 11 for storing the impregnating substance.

After the conclusion of the impregnation cycle of the stator winding 15, the latter is hung out to drain the impregnating substance.

Moreover, the time of washing, impregnation of the stator winding 15 is fixed in a discrete-analog control line 14 with subsequent transfer to the technological protocol.

The conducted studies in the depot showed the high efficiency of the process of cleaning the impregnation of the stator winding 15 in the impregnating substance using ultrasound.

Claims (4)

1. Installation of impregnation of the windings of the stators of asynchronous auxiliary electric motors, consisting of a container with an impregnating substance and an ultrasonic system, characterized in that there is a container for storing the impregnating substance, connected by a pipe to a container for impregnating through a filter, both containers equipped with heating elements, a level gauge, a temperature sensor pressure gauge and connected to a vacuum system, the impregnation tank is equipped with ultrasonic emitters, and the storage tank is connected to the systems compressed air. 2. Installation of impregnation of the windings of stators of asynchronous auxiliary electric motors according to claim 1, characterized in that the ultrasonic emitters are installed opposite the upper and lower parts of the winding uniformly around the circumference. 3. A method of impregnating the windings of stators of asynchronous auxiliary electric motors, including heating the impregnating substance and creating ultrasonic vibrations in the impregnation vessel, characterized in that after installing the stator winding of the motor in the impregnation vessel, it is heated until water vapor is removed from the winding, after the winding has cooled down to 60 -70 ° C, the impregnation container is filled with an impregnating substance previously heated in the storage container, turning on the ultrasonic emitters, create cavitation in the impregnating substance, applying This creates air bubbling and using the created shock waves in the impregnating substance, the stator winding is cleaned of dirt, then the impregnating substance is pumped through the filter into the storage container and vacuumized by removing air, the impregnating substance is pumped into the impregnation container, vacuum again and removed air, create cavitation using ultrasonic vibrations in the impregnating substance, providing with the help of shock waves deep impregnation of the stator winding. 4. The method of impregnation of the stator windings of asynchronous auxiliary electric motors according to claim 3, characterized in that the stator winding is heated to a temperature of 120-140 ° C and held at this temperature until water is removed.

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