Simulation prediction method for the effect of internal atmosphere on contact resistance of sealed electromagnetic relay

Abstract

The present invention discloses a simulation prediction method for the influence of the internal atmosphere of a sealed electromagnetic relay on the contact resistance of a contact. The method records and analyzes the type and content changes of the internal atmosphere of a sealed electromagnetic relay through important data records of the past, infers the chemical reactions that may occur during the life test, uses COMSOL Multiphysics simulation software to simulate the generation of organic film and carbon deposition on the contact surface of the sealed electromagnetic relay, records the internal atmosphere composition and content of the sealed electromagnetic relay in the simulation results, and observes whether the corresponding metal oxide is generated on the contact surface, quantifies the recorded generation of organic film and carbon deposition on the contact surface of the sealed electromagnetic relay as a part of the contact resistance of the sealed electromagnetic relay, and infers the failure threshold of the sealed electromagnetic relay according to the contact resistance after failure. The prediction simulation method of the present invention can solve the problems of quantifying carbon deposition on the contact resistance of the sealed electromagnetic relay contact and calculating the failure threshold.

Description

Technical Field

[0001] The invention relates to a method for predicting the influence of the internal atmosphere of a sealed electromagnetic relay on the contact surface, and in particular to a method for predicting the influence of the internal atmosphere of a sealed electromagnetic relay on the contact resistance and failure threshold of the contact based on simulation analysis. Background Art

[0002] The atmosphere inside a sealed electromagnetic relay is often an important factor that is often overlooked and affects the performance of the relay. There are multiple gas release processes inside the sealed relay, and the released gases generally include oxygen, nitrogen, water vapor, carbon dioxide, hydrogen, and a small amount of organic matter. During the operation of the sealed electromagnetic relay, a small amount of carbon deposits will appear on the contact surface. As the frequency of the sealed electromagnetic relay increases, the carbon deposit content gradually increases and diffuses to the contact surface, which will affect the size of the contact resistance, change the contact morphology, and ultimately affect the performance and arcing time of the electromagnetic relay, reduce the life of the electromagnetic relay, and make it difficult to accurately evaluate the performance consistency and reliability of the entire relay product.

[0003] Predicting the influence of the internal atmosphere of the sealed electromagnetic relay on the contact surface is beneficial to the selection of the contact material of the sealed electromagnetic relay and the control of the internal atmosphere. By inspecting the internal atmosphere composition and content of the sealed electromagnetic relay and the control of the number of life experiments, the chemical simulation model is used to calculate the carbon deposition and organic film generation on the contact surface to quantify the corresponding contact resistance, simplify the failure model, and predict the failure threshold of the sealed electromagnetic relay. However, the above method is based on theoretical analysis to establish a simplified model. Appropriate adjustment of different chemical reactions will result in certain errors in the amount of carbon deposition and organic film generation, which needs to be improved urgently. Summary of the invention

[0004] The purpose of the present invention is to provide a simulation prediction method for the influence of the internal atmosphere of a sealed electromagnetic relay on the contact resistance of the contacts, which is used to solve the influence of carbon deposition and organic film on the contact resistance in complex chemical reactions, and predict the failure threshold of the sealed electromagnetic relay through quantitative calculation.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A simulation prediction method for the influence of the internal atmosphere of a sealed electromagnetic relay on the contact resistance of contacts comprises the following steps:

[0007] Step S1: by analyzing the type and content changes of the internal atmosphere of the sealed electromagnetic relay through the important data records of the past, the chemical reactions that may occur during the life test are inferred, wherein: the data records include the internal atmosphere composition and content of the sealed electromagnetic relay at the beginning of the residual atmosphere test (RGA) and after the life test, the number of life tests, the contact resistance of the sealed electromagnetic relay after failure, and the corresponding ambient temperature and pressure, and the internal atmosphere composition includes nitrogen, oxygen, argon, carbon dioxide, water, and hydrogen;

[0008] Step S2: using COMSOL Multiphysics simulation software, input the contact composition, the composition and content of the atmosphere inside the initial sealed electromagnetic relay, set the chemical reaction type and the closed environment simulation model, set the ambient temperature to 125°C, the pressure to 110 kPa, convert the number of life tests into the total reaction time, and start the simulation;

[0009] Step S3: waiting for the running results of COMSOL Multiphysics simulation software, recording the amount of organic film and carbon deposition generated on the contact surface of the sealed electromagnetic relay and the composition and content of the atmosphere inside the sealed electromagnetic relay in the simulation results, and observing whether corresponding metal oxides are generated on the contact surface;

[0010] Step S4: quantifying the amount of organic film and carbon deposition on the contact surface of the sealed electromagnetic relay as a part of the contact resistance of the sealed electromagnetic relay by a certain method, and calculating the failure threshold of the sealed electromagnetic relay according to the contact resistance after failure;

[0011] Step S5: Compare the internal atmosphere composition and content of the sealed electromagnetic relay after the simulation and the life test. If the error between the final content of the internal atmosphere and the simulation result does not exceed 10%, the prediction scheme is relatively feasible; if the error between the final content of the internal atmosphere and the simulation result exceeds 10%, it is necessary to redefine the reaction type and simulation model, re-simulate the quantified contact resistance and calculate the failure threshold;

[0012] Step S6: Simulate according to the modified quantitative contact resistance method, the initial internal atmosphere composition and content, the ambient temperature and pressure to predict the contact resistance and failure threshold of the contacts of the same type of sealed electromagnetic relays.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] The prediction simulation method of the present invention can solve the problems of quantifying carbon on the contact surface of a sealed electromagnetic relay and calculating the failure threshold, and make corresponding equivalence for the contact resistance caused thereby, thereby providing a more convenient contact resistance evaluation method and improving the accuracy of the evaluation of the life of a sealed electromagnetic relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart for predicting the effect of the internal atmosphere of a sealed electromagnetic relay on the contacts;

[0016] Figure 2 It is a simulation model of sealed electromagnetic relay contacts;

[0017] Figure 3 This is a graph showing the percentage of simulated gas content. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0019] The present invention provides a method for predicting the influence of the internal atmosphere of a sealed electromagnetic relay on the contact resistance and failure threshold based on simulation analysis. The method records important data of previous sealed electromagnetic relays and analyzes the changes in the types and contents of the internal atmosphere, infers the chemical reactions that may occur during the life test, and uses COMSOL Multiphysics simulation software to simulate the generation of organic films and carbon deposits on the contact surfaces of the sealed electromagnetic relays. The composition and content of the internal atmosphere of the sealed electromagnetic relay in the simulation results are recorded, and it is observed whether corresponding metal oxides are generated on the contact surfaces. The recorded generation of organic films and carbon deposits on the contact surfaces of the sealed electromagnetic relays is quantified as a part of the contact resistance of the sealed electromagnetic relay, and the failure threshold of the sealed electromagnetic relay is calculated based on the contact resistance after failure. Figure 1 As shown, the specific steps include:

[0020] Step S1: By analyzing the important data records of the previous sealed electromagnetic relays, the types and content changes of the internal atmosphere are analyzed to infer the chemical reactions that may occur during the life test, wherein: the data records include the internal atmosphere composition and content of the sealed electromagnetic relay at the beginning of the residual atmosphere experiment (RGA) and after the life test, the number of life tests, the contact resistance of the sealed electromagnetic relay after failure, and the corresponding ambient temperature and pressure. The types of internal atmosphere are shown in Table 1.

[0021] Table 1 Gas composition inside sealed electromagnetic relay

[0022] Component name English name CAS Number Chemical formula Nitrogen Nitrogen 7727-37-9 <![CDATA[N2 <!-- 2 -->]]> oxygen Oxygen 7782-44-7 <![CDATA[O2]]> Argon Argon 7440-37-1 Ar carbon dioxide Carbon Dioxide 124-38-9 <![CDATA[CO2]]> water Water 7732-18-5 <![CDATA[H2O]]> hydrogen Hydrogen 1333-74-0 <![CDATA[H2]]> ...... ...... ...... ......

[0023] Step S2: Using COMSOL Multiphysics simulation software, input the contact composition, the composition and content of the atmosphere inside the initial sealed electromagnetic relay, set the chemical reaction type and the closed environment simulation model, set the ambient temperature to 125°C, the pressure to 110 kPa, convert the number of life tests into the total reaction time, and start the simulation.

[0024] Step S3: Wait for the running results of COMSOL Multiphysics simulation software, record the amount of organic film and carbon deposition on the contact surface of the sealed electromagnetic relay and the composition and content of the atmosphere inside the sealed electromagnetic relay in the simulation results, and observe whether the corresponding metal oxide is generated on the contact surface. The simulation model of the sealed electromagnetic relay contact is as follows: Figure 2 shown.

[0025] Step S4: The amount of organic film and carbon deposition on the surface of the sealed electromagnetic relay contact is quantitatively analyzed by SEM to determine the content and surface morphology, and the contact area of ​​the microscopic surface is calculated. The resistivity of the organic film and carbon is calculated as part of the contact resistance of the sealed electromagnetic relay, and the failure threshold of the sealed electromagnetic relay is calculated based on the contact resistance after failure. The contact resistance threshold is usually 50mΩ.

[0026] Step S5: Compare the internal atmosphere composition and content of the sealed electromagnetic relay after simulation and life test. If the error between the final content of the internal atmosphere and the simulation result does not exceed 10%, the prediction scheme is relatively feasible; if the error between the final content of the internal atmosphere and the simulation result exceeds 10%, it is necessary to redefine the reaction type and simulation model, re-simulate the quantitative contact resistance and calculate the failure threshold.

[0027] Step S6: Simulate according to the modified quantitative contact resistance method, the initial internal atmosphere composition and content, the ambient temperature and pressure to predict the contact resistance and failure threshold of the contacts of the same type of sealed electromagnetic relays.

[0028] The percentage of gas simulation content is shown in the figure Figure 3 As shown. Argon is an inert gas. The reactions of other gases are more complicated and all of them participate in the reaction. Therefore, only argon is used as the criterion. The argon content increases after the reaction, indicating that the reaction reduces the total gas content and no new gas appears. According to the actual test results, there is obvious solid on the contact surface, so the reaction only produces solid. Next, you only need to know the molar amount or mass of argon to calculate the molar amount of each gas reduced or increased, and then list the equations from chemical equations such as 2Mg+CO2=2MgO+C, CO2+2H2=2H2O+C, C+O2=CO2 to calculate the carbon deposit amount.

Claims

1. A simulation prediction method for the influence of the internal atmosphere of a sealed electromagnetic relay on the contact resistance of the contacts, characterized in that The method comprises the following steps: Step S1: by recording important data of the previous sealed electromagnetic relay, analyzing the type and content changes of the internal atmosphere, and inferring the chemical reactions that may occur during the life test; Step S2: using COMSOL Multiphysics simulation software, input the contact composition, the composition and content of the atmosphere inside the initial sealed electromagnetic relay, set the chemical reaction type and the closed environment simulation model, set the ambient temperature to 125°C, the pressure to 110 kPa, convert the number of life tests into the total reaction time, and start the simulation; Step S3: waiting for the running results of COMSOL Multiphysics simulation software, recording the amount of organic film and carbon deposition generated on the contact surface of the sealed electromagnetic relay and the composition and content of the atmosphere inside the sealed electromagnetic relay in the simulation results, and observing whether corresponding metal oxides are generated on the contact surface; Step S4: quantifying the amount of organic film and carbon deposition on the contact surface of the sealed electromagnetic relay as a part of the contact resistance of the sealed electromagnetic relay, and calculating the failure threshold of the sealed electromagnetic relay according to the contact resistance after failure; Step S5: Compare the composition and content of the internal atmosphere of the sealed electromagnetic relay after the simulation and the life test. If the error between the final content of the internal atmosphere and the simulation result does not exceed 10%, the prediction scheme is relatively feasible. If the error between the final content of the internal atmosphere and the simulation result exceeds 10%, it is necessary to redefine the reaction type and simulation model, re-simulate the quantified contact resistance and calculate the failure threshold; Step S6: Simulate according to the modified quantitative contact resistance method, the initial internal atmosphere composition and content, the ambient temperature and pressure to predict the contact resistance and failure threshold of the contacts of the same type of sealed electromagnetic relays.

2. The simulation prediction method for the influence of the internal atmosphere of the sealed electromagnetic relay on the contact resistance according to claim 1 is characterized in that The data records include the internal atmosphere composition and content of the sealed electromagnetic relay at the beginning of the residual atmosphere test and after the life test, the number of life tests, the contact resistance of the sealed electromagnetic relay after failure, and the corresponding ambient temperature and pressure.

3. The simulation prediction method for the influence of the internal atmosphere of the sealed electromagnetic relay on the contact resistance according to claim 1 is characterized in that The internal atmosphere comprises nitrogen, oxygen, argon, carbon dioxide, water and hydrogen.

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