Research on the Reliability Tolerance Analysis Method of Electromagnetic Relay in Aerospace

Electromagnetic relay in aerospace is one of the main electronic components in aerospace electronic systems for information transfer, control and power distribution, and its reliability will influence the reliability of the whole aerospace electronic systems. Reliability design is the key technique of electromagnetic relay reliability engineering. This paper synthetically analyzes the present reliability design methods, and presents the reliability tolerance analyzing mathematic models of electromagnetic force basing on orthogonal design, mechanical spring force basing on probability statistics theory, and matching characteristics of electromagnetic force and mechanical spring force basing on method of stressstrength interference. Some instructive conclusions are draw by researching on the reliability tolerance of some type electromagnetic relay in aerospace.

Research on electromagnetic relay's dynamic characteristics disturbed by uniform static magnetic field

Electromagnetic relay is a widely used apparatus which usually works in a magnetic disturbance environment. To evaluate its electromagnetic compatibility (EMC) in a static magnetic field, dynamic characteristics of a clapper relay in a uniform static magnetic field situation based on the finite element method (FEM) is studied. Influences of the magnetic field on dynamic parameters (delay time, pick-up time, end pressure, and final velocity) as well as a situation in which the relay cannot function normally are analyzed. Simulation reveals that the external magnetic field which weakens the relay’s air-gap field has a greater influence on the relay’s dynamic parameters than the one strengthening the field. The validity of the simulation is verified by measured results of coil current and armature displacement.

Influence of the ambient air temperature on the electrical contact reliability of electromagnetic relay

The dynamic contact resistances of HH52P electromagnetic relays are measured under different ambient air tem- perature. Their diagnostic parameters are extracted and determined. It is found that the ambient air temperature obviously influ- ences some parameters. In order to research its influence on the electrical contact reliability of electromagnetic relay, the statistic analysis is applied to study the static contact resistance, the max of the dynamic contact resistance and the bounce time. It is found that the ambient air temperature regularly influences the three parameters. Thoroughly, the phenomenon is studied and analyzed in the point of material science so as to probe into the essential matter of it.

Discussion on dynamic reliability tolerance design technology of electromagnetic relay

Reliability tolerance design of electromagnetic relay during its design period plays an essential role in guaranteeing the consistencies of reliability and output characteristic. The reliability tolerance design can ensure that the products would work well under the influence of disturbing factors (including internal interference, external interference, and machining dispersion). Com- pared with static characteristic, dynamic characteristic of electromagnetic relay can describe its operating process better. This article researches influence of the three kinds of disturbing factors on the dynamic characteristic of electromagnetic relay based on calculating dynamic characteristic. Then, the dynamic reliability tolerance design method of electromagnetic relay is discussed considering three kinds of disturbing factors. Conclusions reached can help to assure the reliability of electromagnetic relay from the beginning of design.

Method of analyzing vibration characteristics of armature system of hermetically sealed electromagnetic relay

Published research is minimal on vibration characteristics of hermetically sealed electromagnetic relay (EMR) ex- posed to mechanical environment. The vibration characteristics of armature system, link contact system with electromagnetic system will cause EMR malfunction. The nonlinear dynamics model of armature systems was studied by considering electro- magnetic attraction force and opposite mechanical force in this paper. Angular displacements of armature under different sinu- soidal vibration conditions are solved in order to obtain the failure mode result from armature system. Vibration tests showed the presented analyzing method is suitable for EMR. The conclusions are instructive for increasing vibration resistance of armature systems of EMR, and are significant for reliability design of switch apparatus.

Optimization design method of contact bounce and breakaway initial velocity for aerospace electromagnetic relay

Aerospace electromagnetic relay is an electric component that has been widely used in aerospace industry.Contact bounce and contact breakaway for initial velocity are the key parameters that have strong influence on reliability and electric life of the relay.Generally,it is difficult to optimize these two parameters simultaneously.In this paper,according to kinetics theory and structural mechanics,a dynamic reaction calculation model of the relay that describes contact bounce and breakaway for initial velocity is proposed.Under the constraints of contact gap and contact force,the optimal combination of debugging parameters is obtained by the application of orthogonal design.It considers the reduction of contact bounce and the augmentation of breakaway for initial velocity as the optimization objectives,and takes the debugging parameters as the optimization variables.All these above ensure the increase of contact breakaway for initial velocity and the decrease of contact bounce simultaneously,and contact arc erosion is also reduced.

A robust solution for hesitate phenomenon in pick up process of aerospace electromagnetic relay

As for aerospace electromagnetic relay （AEMR） which is of small batches and having difficulty in automatic production, the uncertainty phenomenon is remarkable due to excessive manual work involved in the assembly and adjustment processes. This kind of uncertainty may increase the coil voltage difference （CVD） caused by hesitate phenomenon in the pick up process of AEMR. Taking a certain type of AEMR for example, the CVD problem in the actual producing process has been studied in this paper. The primary cause of this issue, two-steps of armature motion （namely hesitate phenomenon） in the pick up process, has been found by analyzing the matching characteristics of electromagnetic and mechanical torques of AEMR. Through the optimization of the matching characteristics, the two-steps of armature motion problem is solved by robust design of the return reed which is a key part of AEMR. The validity of this research has been proved by the comparison of characteristics of AMER before and after the optimization.

Plant Cultivation Device in Intelligent Agricultural Greenhouse

This paper mainly introduces the design and research of plant cultivation device in intelligent agricultural greenhouse.The device can automatically ventilate and control the temperature when the carbon dioxide content is insufficient.At the same time,the light color can be selected according to the plant properties,and the light and dark time can be controlled to provide a suitable growth environment for plants,which makes up for the shortcomings of the existing ordinary greenhouse.With China's strong support for agriculture,automatic agriculture is developing rapidly,and has a broad market prospect.

A novel matrix topology-based analysis method of thermal circuits for reliability optimization of HSER

Hermetically Sealed Electromagnetic Relay(HSER), used in aviation and aerospace,demands high reliability due to its critical applications. Given its complex operating conditions, efficient thermal analysis is essential for optimizing reliability. The commonly used Finite Element Method(FEM) is often time-consuming and may not be efficient or adaptable for complex multi-dimensional system calculations and design processes. This paper introduces an analysis method for thermal networks based on matrix perspective technology, encompassing matrix transformation, backpropagation of the heat path model, temperature rise calculation, solution comparison, and product implementation. Using the similarity theory of heat circuits, a basic thermal unit is established. Based on the fundamental connection between key components, a thermal network for a typical HSER is designed. An experimental system is set up, and the thermal network model's accuracy is confirmed using test data. Employing the topology analysis method, the topology of the thermal network is analyzed under both coil-energized and de-energized states. Potential thermal paths are identified, leading to optimized solutions for the HSER. Utilizing these solutions, the thermal path matrix topology model is backpropagated to the thermal path for temperature rise calculations. When compared to prototype HSER test data, the efficiency and accuracy of this matrix topology-based analysis method are confirmed.

A multi-parameter model of heat treatment process for soft magnetic materials on performance of HSERs

Abstract:Material properties play an important role in the performance of electromagnetic mechanism. For an aeronautic Hermetically-Sealed Electromagnetic Relay(HSER), more than 50%parts are made of soft magnetic materials. Therefore, the performance of soft magnetic materials directly determines the static and dynamic characteristics of the HSER. Based on the theory of crystal recrystallization, this paper analyzes cold extrusion and heat treatment in the processing of soft magnetic materials, simulates the grain change process of an armature at different heat treatment temperatures, establishes a correlation model of temperature, grain size, and magnetic energy,and verifies results by scanning electron microscopy. Results of heat treatment temperatures from 800 ℃to 920 ℃are obtained and compared. A sample soft magnetic material after heat treatment at different temperatures has the largest difference in the initial magnetization range, up to 22%. In order to verify the fluctuation of the overall output characteristics of an HSER caused by the difference between soft magnetic materials, a static and dynamic analysis model of a typical HSER is established, and the accuracy of the model is verified by a set of actual test system. The difference of dynamic characteristics under different heat treatment temperatures is nearly 3%.