RU2536669C1 - Method of monitoring and visualisation of operation of commutator-and-brush assembly of dc motor - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: invention relates to the automated monitoring and smart diagnostics of electrical machines. The offered method includes the measurement of the temperature of rotor windings, anchor windings current, rotor angular velocity, sparking parameter, and length of bruches, the measured values are converted into numerical codes and transmitted into the computer device and further to the operator panel. In the memory of the computer system the model of mechanical characteristics of motor is saved, the animated image of sparking of the commutator-and-brush assembly and the position of the working point of the motor in a plane of parameters "current - speed" against the background of the mechanical performance are synthesised, the coefficients of correlation between the parameter ξ, characterising the sparking, and the current i of the motor r_ξi and the coefficient of correlation between the parameter ξ, characterising the sparking, and angular velocity Ω of the motor r_ξi in the sliding time interval vs the values of windings temperature, rotor angular velocity, current, length of brushes, parameter characterising the sparking, coefficients of correlation r_ξi and r_ξΩ, the mode of motor operation is identified.

EFFECT: improvement of accuracy of detection of the reason of sparking of commutator-and-brush assembly.

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Description

The present invention relates to automated control and intelligent diagnosis of electrical machines.

Known methods for monitoring and visualizing the operation of the brush-collector assembly of an electric DC motor, in which a parameter characterizing sparking is measured, displaying and comparing the measured value with an acceptable value (RF Patent No. 2303272, IPC G01R 31/34. Publ. 20.07.2007. - Bull. No. 20; AS USSR No. 1810955, IPC H02K 13/14. Publish. 04.23.93. - Bull. No. 15; Komarov SG. Device for monitoring sparking on the collector of an electric DC machine // Modern engineering and technology. - January, 2013 [Electronic resource]. URL: http://technology.snayka.ru/2013/01/1459).

Known methods allow you to control the sparking of the motor brushes and take measures to timely eliminate the causes of malfunctions. However, when using the known method, the wear of the brushes is not controlled and the causes of sparking are not determined.

Therefore, the disadvantages of the known methods are limited functionality and insufficient reliability of the control of the brush-collector assembly of an electric DC motor.

Of the known technical solutions, the closest to the proposed achieved result is a method for monitoring and visualizing the operation of the brush-collector assembly of an electric DC motor, in which the temperature of the rotor windings, the current of the armature winding, the rotor angular velocity, the parameter characterizing sparking are converted, the measured values are converted into digital codes and transmit them to a computing device, such as a computer, with the help of which they display, register and compare the measured values with valid values, and generation of signals for protection system (U.S. Patent №7873581, G06F 15/18; G06G 7/00, 2011).

When implementing the known method, the operation of the components of the DC electric motor is controlled by obtaining information about the current values of the variables characterizing the operation of the machine elements, including the parameter characterizing sparking, the current of the armature winding, the angular speed of rotation of the rotor and the temperature of the rotor windings. However, when using the known method, the wear of the brushes is not controlled and the causes of sparking are not determined.

The disadvantages of this method are the limited functionality and lack of reliability of the brush-collector assembly of an electric DC motor.

The purpose of the invention is to expand the functionality and increase the reliability of the control of the brush-collector assembly of an electric DC motor.

This goal is achieved by the fact that in the known method of monitoring and visualizing the operation of the brush-collector assembly of an electric DC motor, in which the temperature of the rotor windings, the current of the armature winding, the rotor angular velocity, the parameter characterizing the sparking are measured, the measured values are converted to digital codes and transmitted them into a computing device, such as a computer, with the help of which they display, register and compare measured values with acceptable values and generate signals for For protection systems, the brush lengths are additionally measured, the model of the mechanical characteristics of the engine is stored in the memory of the computing device, an animated image of the sparking of the brush-collector assembly and the position of the motor operating point in the plane of the current-speed parameters against the background of the mechanical characteristic are synthesized, and estimates of the correlation coefficients between the parameter ξ are calculated characterizing arcing and current i r _ξi engine and the correlation coefficient between the parameter ξ, characterizing arcing, and the angular velocity Ω dd tor r _ξΩ on a sliding time interval depending on the winding temperature values, angular velocity, current, brush length parameter indicative of arcing, r _ξi correlation coefficients, and r _ξΩ determined engine operation mode belongs to a field of normal, acceptable or emergency operation, detected cause sparking, is recorded in the memory of the computing device and displaying the value of the length of brushes and correlation coefficients r _ξi and r _ξΩ, and the message engine operation and possible arcing due to eq monitor Ana.

Compared with the closest similar technical solution, the proposed solution includes the following new operations:

- measure the length of the brushes;

- store in the memory of the computing device a model of the mechanical characteristics of the engine;

- synthesize an animated image of the sparking of the brush-collector assembly and the position of the motor operating point in the plane of the current-speed parameters against the background of a mechanical characteristic;

- calculate the correlation coefficients between the parameter ξ characterizing the sparking, and the current i of the motor r _ξi and the correlation coefficient between the parameter ξ characterizing the sparking, and the angular velocity Ω of the motor r _ξΩ on a moving time interval;

- depending on the values of the temperature of the windings, the angular velocity of the rotor, the current, the length of the brushes, the parameter characterizing the sparking, the correlation coefficients r _ξi and r _ξΩ determine the belonging of the motor operating mode to the range of normal, permissible or emergency conditions and determine the cause of sparking;

- register the values of the brush lengths and estimates of the correlation coefficients r _ξi and r _ξΩ in the memory of the computing device;

- display values of the length of the brushes and the correlation coefficients r _ξi and r _{ξ ξ Ω} , as well as a message about the engine operating mode and the probable cause of arcing on the monitor screen.

Therefore, the claimed technical solution meets the requirement of "novelty."

When implementing the invention, the reliability and reliability of monitoring the parameters of the DC motor is increased, since the visibility and accessibility of information about the state of the brush-collector assembly is ensured.

Therefore, the claimed technical solution meets the requirement of "positive effect".

For each distinguishing feature, a search is made for well-known technical solutions in the field of electrical engineering, automation, control and diagnostics.

The operation of measuring the length of the brushes is used in a known method for a similar purpose (SIMOREG DC-MASTER 6RA70 // Siemens. - 2001 [Electronic resource]. URL: http://www.siemens-ru.com/images/siemens/docs/System_description.pdf )

The operation of processing electrical signals by calculating the correlation coefficient between the parameter ξ characterizing the sparking and the current i of the motor r _ξi and the correlation coefficient between the parameter ξ characterizing the sparking and the angular velocity Ω of the motor r _ξΩ on a moving time interval were not found in the known methods for a similar purpose.

The operation of determining the cause of sparking by determining whether the values of the temperature of the windings, rotor angular velocity, current, brush length, parameter characterizing sparking, and correlation coefficients r _ξi and r _{ξΩ belong} to the normal, permissible, or emergency mode of operation of the motor are not found in the known methods for a similar purpose.

The operation of synthesizing an animated image of the sparking process in known technical solutions of a similar purpose was not found.

Thus, these features provide the claimed technical solution according to the requirement of "significant differences".

When implementing the proposed method, full control of the brush-collector assembly is carried out by measuring the temperature of the windings, the parameter characterizing sparking, current, angular speed of the motor and the length of the brushes. Based on the data of continuous measurements, the correlation coefficient between the parameter ξ characterizing the sparking and the current i of the motor r _ξi and the correlation coefficient between the parameter ξ characterizing the sparking and the angular velocity Ω of the motor r _ξΩ over a moving time interval are _calculated , the values of which allow determining the probable cause of sparking and evaluate the condition of the brush-collector assembly of the engine depending on the belonging of the operating point in the space of controlled parameters to the normal, permissible or iynyh modes. Computer visualization of the work of the brush-collector unit provides the possibility of continuous subjective assessment of the state of the electric machine through remote monitoring.

Therefore, the claimed technical solution meets the requirement of "positive effect".

The essence of the invention is illustrated by drawings. Figure 1 shows a functional diagram of a system for monitoring and visualizing the operation of the brush-collector assembly. Figure 2 shows a screen view of an operator panel with an animated image of a brush-collector assembly. In Fig.1 indicated: 1 - multi-channel analog-to-digital Converter; 2 - rotor angular velocity sensor; 3 - electric motor DC; 4 - computing device, such as a computer; 5 - operator panel; 6 - brush length sensor; 7 - sensor parameter characterizing the sparking; 8 - temperature sensor of the rotor windings; 9 - current sensor of the armature winding; 10 - voltage converter; 11 - data bus.

The system operates as follows. The signals from the sensors of the angular speed of the rotor 2, the length of the brushes 6, the parameter characterizing the sparking 7, the temperature of the rotor windings 8 and the current of the armature winding 8 of the collector electric machine 3, connected to the electric network via the converter 10, are fed to a multi-channel analog-to-digital converter 1, and further along the data bus 11 to a computing device, for example, a computer. The computing device performs the following functions:

- stores in memory a model of the mechanical characteristics of the engine;

- synthesizes the image of the operating point of the motor in the plane of the current-speed parameters against the background of a mechanical characteristic;

- calculates the correlation coefficients r _ξi and r _ξΩ on a moving time interval in accordance with the formulas:

; $$r_{\xi i}=\frac{{\displaystyle \sum _{k=n-N+\mathrm{one}}^n[\xi (k)-\overline{\xi }]\cdot [i(k)-\overline{i}]}}{\sqrt{{\displaystyle \sum _{k=n-N+\mathrm{one}}^n{[\xi (k)-\overline{\xi }]}^2}\cdot {\displaystyle \sum _{k=n-N+\mathrm{one}}^n{[i(k)-\overline{i}]}^2}}}$$

;

, $$r_{\xi \Omega }=\frac{{\displaystyle \sum _{k=n-N+\mathrm{one}}^n[\xi (k)-\overline{\xi }]\cdot [\Omega (k)-\overline{\Omega }]}}{\sqrt{{\displaystyle \sum _{k=n-N+\mathrm{one}}^n{[\xi (k)-\overline{\xi }]}^2}\cdot {\displaystyle \sum _{k=n-N+\mathrm{one}}^n{[\Omega (k)-\overline{\Omega }]}^2}}}$$

,

, $$\overline{i}=\frac{1}{N}{\displaystyle \sum _{k=n-N+1}^{n}i(k)}$$

, $$\overline{\Omega }=\frac{1}{N}{\displaystyle \sum _{k=n-N+1}^n\Omega (k)}$$

, $$n\ge N$$

.Where $$\overline{\xi }=\frac{\mathrm{one}}{N}{\displaystyle \sum _{k=n-N+\mathrm{one}}^n\xi (k)}$$

, $$\overline{i}=\frac{\mathrm{one}}{N}{\displaystyle \sum _{k=n-N+\mathrm{one}}^{n}i(k)}$$

, $$\overline{\Omega }=\frac{\mathrm{one}}{N}{\displaystyle \sum _{k=n-N+\mathrm{one}}^n\Omega (k)}$$

, $$n\ge N$$

.

n is the base point on the time axis, N is the number of samples on a moving time interval;

и $$r_{\xi \Omega }\approx 0$$

, то искрение отсутствует, если $$r_{\xi i}>>r_{\xi \Omega }$$

, то причины искрения электромагнитные и искры изображаются голубым цветом, если $$r_{\xi i}<<r_{\xi \Omega }$$

, то причины искрения механические и искры изображаются зеленым цветом, если $$r_{\xi i}\approx r_{\xi \Omega }$$

и $$r_{\xi i}>>0$$

, то причины искрения смешанные и искры изображаются одновременно зеленым и голубым цветами;- synthesizes an animated image of the sparking of the brush-collector assembly, according to the following scheme: if $$r_{\xi i}\approx 0$$

and $$r_{\xi \Omega }\approx 0$$

then there is no sparking if $$r_{\xi i}>>r_{\xi \Omega }$$

then the causes of electromagnetic sparking and sparks are shown in blue if $$r_{\xi i}<<r_{\xi \Omega }$$

, then the causes of mechanical sparking and sparks are shown in green, if $$r_{\xi i}\approx r_{\xi \Omega }$$

and $$r_{\xi i}>>0$$

, then the causes of sparking are mixed and sparks are depicted simultaneously in green and blue;

- depending on the values of the temperature of the windings, the angular velocity of the rotor, current, brush length, the parameter characterizing the sparking, the correlation coefficients r _ξi and r _ξΩ determines the belonging of the motor operating mode to the range of normal, permissible or emergency conditions and determines the cause of sparking;

- registers the values of the brush lengths and estimates of the correlation coefficients r _ξi and r _ξΩ in the memory of the computing device;

- determines whether the operating mode of the engine belongs to the area of normal, permissible or emergency conditions. The areas of normal, permissible and emergency conditions are defined by systems of inequalities:

- for normal modes:

$$\{\begin{array}{l}|\; |\; |i|\; |\; |\le I_N;\\ |\; |\; |\Omega |\; |\; |\le {\Omega }_N;\\ \theta \le {\theta }_N;\\ \xi \le {\xi }_N;\\ l\ge l_N,\end{array}\text{(one)}$$

where I _n , Ω _n , ξ _n , l _n - the values of the boundaries of the current, speed, parameter characterizing the sparking, and the length of the brushes for normal operation;

- for valid modes:

$$\{\begin{array}{l}|\; |\; |i|\; |\; |\le I_d;\\ |\; |\; |\Omega |\; |\; |\le {\Omega }_d;\\ \theta \le {\theta }_d;\\ \xi \le {\xi }_d;\\ l\ge l_d,\end{array}\text{(2)}$$

where I _d , Ω _d , ξ _d , l _d are the values of the boundaries of the current, speed, parameter characterizing the sparking, and the length of the brushes for the permissible mode of operation;

- for emergency operation:

$$\{\begin{array}{l}|\; |\; |i|\; |\; |>I_d;\\ |\; |\; |\Omega |\; |\; |>{\Omega }_d;\\ \theta >{\theta }_d;\\ \xi >{\xi }_d;\\ l>l_d.\end{array}\text{(3)}$$

If all the variables are in the normal ranges of values in accordance with (1), the engine operating mode is considered normal. If at least one of the parameters leaves the interval corresponding to the normal mode, and at the same time, none of the parameters goes beyond the boundaries of the interval corresponding to the allowable mode defined by system (2), the engine operation mode is considered valid. If at least one of the parameters leaves the interval corresponding to the permissible operating mode, then in this case the engine operates in the emergency mode, which is set by the system (3).

It is known that the sparking of brushes can be caused by many reasons, the main of which are mechanical (mechanical sparking) and electromagnetic (electromagnetic sparking) (Mandych N.K. Repair of electric motors. Manual for electrician // Kiev. Tehnika. 1989. - 152 p. )

The mechanical causes of sparking are independent of the load. With mechanical sparking, sparks of green color spread across the entire width of the brush, the burnout of the collector is not regular, random. Mechanical sparks of brushes are caused by: local or general runout, scuffing on the sliding surface of the collector, scratches protruding from the mica, poor path of the collector (cutting of mica between the collector plates), tight or weak fit of the brushes in the holders of the brush holders, malleability of the brakes causing vibration of the brushes, vibration and etc.

The electromagnetic causes of sparking brushes are more complex in terms of identifying them. Sparking caused by electromagnetic phenomena varies in proportion to the load and depends little on the speed. Electromagnetic sparking is usually blue and white. The shape of the sparks is spherical or droplet-shaped. Burnout of collector plates is of a natural nature, by which it is possible to determine the cause of sparking. If a short circuit occurs in the winding and equalizers, the soldering is broken or a direct break occurs, the sparking will be uneven under the brushes, and the burnt plates will be located along the collector at the distance of one pole division. If the brushes sparkle under the brackets of one pole more than under the brackets of the other poles, then a winding or short circuit in the windings of individual main or auxiliary poles has occurred; brushes are incorrectly located or their width is more than admissible.

и $$r_{\xi \Omega }\approx 0$$

, то искрение отсутствует, если $$r_{\xi i}>>r_{\xi \Omega }$$

, то причины искрения электромагнитные и искры изображаются голубым цветом, если $$r_{\xi i}<<r_{\xi \Omega }$$

, то причины искрения механические и искры изображаются зеленым цветом, если $$r_{\xi i}\approx r_{\xi \Omega }$$

и $$r_{\xi i}>>0$$

, то причины искрения смешанные и искры изображаются одновременно зеленым и голубым цветами.In order to identify the probable cause of sparking in the proposed method, the correlation coefficients r _ξi and r _{ξΩ are calculated} , then the cause of sparking is determined from them according to the following scheme: if $$r_{\xi i}\approx 0$$

and $$r_{\xi \Omega }\approx 0$$

then there is no sparking if $$r_{\xi i}>>r_{\xi \Omega }$$

then the causes of electromagnetic sparking and sparks are shown in blue if $$r_{\xi i}<<r_{\xi \Omega }$$

, then the causes of mechanical sparking and sparks are shown in green, if $$r_{\xi i}\approx r_{\xi \Omega }$$

and $$r_{\xi i}>>0$$

, then the causes of sparking are mixed and sparks are depicted simultaneously in green and blue.

As a parameter characterizing the sparking, it is possible to use the intensity of electromagnetic radiation induced on the receiving antenna of the sparking sensor. It has been established that the signal spectrum recorded by the spark intensity sensor on the collector of an electric DC machine is a function that determines the magnitude of the component’s amplitude depending on its frequency and the amount of electromagnetic energy released (Komarov S.G. A device for monitoring sparking on the collector of an electric DC machine // Modern equipment and technologies. - January, 2013 [Electronic resource]. URL: http://technology.snauka.ru/2013/01/1459).

Brush sparking is measured in points. Normal operation of a DC machine is considered to be weak point sparking under a small part of the brush (1/4 point). Sparking under the entire edge of the brush (2 points) is allowed only during transient conditions and short-term overloads. Strong sparking (3 points) is not allowed under any circumstances. If such sparking occurs, the machine should be immediately disconnected from the network and inspected and, if necessary, repaired (Wind energy, wind generators - technologies and developments // DC generators. Machine armature. Armature winding. - January, 2011 [Electronic resource] URL: http : //vetrodvig.ru/? p = 1313).

Thus, the use in the known method of monitoring and visualizing the operation of the brush-collector assembly of a DC electric motor, in which the temperature of the rotor windings, the current of the armature winding, the rotor angular velocity, the parameter characterizing the sparking are measured, the measured values are converted to digital codes and transmitted to a computing device, for example, a computer, with the help of which display, registration and comparison of measured values with acceptable values and the formation of signals for systems are performed protection, in addition, operations for measuring the length of the brushes, storing the model of the mechanical characteristics of the engine in the memory of the computing device, synthesizing an animated image of the sparking of the brush-collector assembly and the position of the motor operating point in the plane of the current-speed parameters against the background of the mechanical characteristic, calculating estimates of the correlation coefficient between the parameter ξ, characterizing the sparking, and the current i of the motor r _ξi and the correlation coefficient between the parameter ξ characterizing the sparking and the angular velocity Ω of the switch r _ξΩ over a moving time interval, depending on the values of the temperature of the windings, rotor angular velocity, current, brush length, parameter characterizing sparking, correlation coefficients r _ξi and r _ξΩ , determining whether the operating mode of the motor belongs to the range of normal, permissible, or emergency conditions , identify the cause sparking, registering of these parameters in a memory of the computing device and displaying the lengths of brushes, r _ξi and correlation coefficients r _ξΩ, and reports of engine operation, and the probability tnoj cause sparking on the screen allows to expand the functionality and improve the reliability of the control operation of brush-commutator assembly of an electric motor of direct current.

Using the proposed method for monitoring the operation of brush-collector assemblies of DC machines in industry will improve the reliability of technological equipment.

Claims (1)

A method for monitoring and visualizing the operation of the brush-collector assembly of an electric DC motor, in which the temperature of the rotor windings, the current of the armature winding, the rotor angular velocity, the parameter characterizing sparking are measured, the measured values are converted into digital codes and transmitted to a computing device, for example a computer, with the help of which they display, register and compare measured values with acceptable values and generate signals for the protection system, characterized in that the addition but they measure the length of the brushes, store a model of the mechanical characteristics of the engine in the memory of the computing device, synthesize an animated image of the sparking of the collector-brush assembly and the position of the motor operating point in the plane of the current-speed parameters against the background of the mechanical characteristic, calculate the values of the correlation coefficients between the parameter ξ characterizing the sparking, and current i r _ξi engine and the correlation coefficient between the parameter ξ, characterizing arcing, and the motor angular speed Ω r _ξΩ on sliding yn ervale time depending on the winding temperature values, angular velocity, current, length brushes parameter indicative of arcing, r _ξi correlation coefficients, and r _ξΩ, determining engine operation mode belongs to a field of normal, acceptable or emergency operation, identify the cause sparking register in the memory of the computing device and display the values of the length of the brushes and the correlation coefficients r _ξi and r _ξΩ , as well as a message about the engine operating mode and the probable cause of sparking on the monitor screen.

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