Electromagnetic Relay Research Articles

Integrated vehicle health management: An approach to dealing with lifetime prediction considerations on relays

Electrical contacts provide a well-proven solution to switching various loads in a wide variety of applications, such as power distribution, control applications, automotive and telecommunications. However, electrical contacts are known for limited reliability due to degradation effects upon switching contacts due to arcing and fretting. Essentially, the life of the device may be determined by the life of the contacts. Failure to trip, spurious tripping and contact welding can, in critical applications such as control systems for avionics and nuclear power application, cause significant costs due to downtime, as well as safety implications.Prognostics provides a way to assess the remaining useful life (RUL) of a component based on its current state of health and its anticipated future usage and operating conditions. In this paper, we examine the effects of contact wear on a set of electromagnetic relays used in an avionic power controller, and how contact resistance combined with a hybrid approach, can be used to ascertain the RUL of the device.

Simulation of Low-Nickel-Content Alloys for Industrial Ground Fault Circuit-Breaker Relays

The aim of this paper is to simulate the performances of a ground fault circuit-breaker (GFCB) relay with new low-nickel-content alloys. Indeed, in the construction industry, the materials become more expensive as their nickel content increases. Moreover, the demand for nickel is particularly sensitive to the economic conjuncture. Therefore, an original electromagnetic relay model has been developed and validated in different working conditions (current amplitude, frequency, and temperature). A dedicated magnetic characterization of materials is needed, using basically a usual and industrial GFCB relay for reference and design data in modeling. First, the magnetic model of the relay is built and checked against experimental data. The simulation may predict the tripping current threshold of the relay. On the other hand, new low-nickel-content alloys for relay parts are studied in this framework, thanks to the developed model. The effects of temperature on the magnetic properties of the candidate materials and the electrical performances of the virtual relays are presented. The results, analysis, and conclusions are given. Finally, a first attempt to predict the economic gain obtained with a change of material is made.

Research on the Optimization of Spring System Based on Virtual Prototyping

The energy of DC arc influences the electrical life and reliability of relay’s contacts seriously. The study on shortening the arc duration by increasing the breaking velocity of contacts is important for reducing the contacts erosion and improving the contacts life. Firstly, it was indicated that increasing the breaking velocity is effective for reducing the arc time of this differential electromagnetic relay through life test, especially the breaking velocity of N.O. contacts. Then a new optimal model of spring system suitable for this relay was analyzed in increasing the breaking velocity. Secondly, electromagnetic model, mechanical model, dynamic simulation model, vibration model and thermal model of the optimal relay were built based on virtual prototyping. Finally, the optimal design was verified on the virtual prototyping platform and the results shows that the breaking velocity of N.O. contacts increases more than 100%, which provides the optimal scheme of improving the relay’s electrical life.

NOVEL SETTING AND DESIGN OF RELAY FOR PROTECTION OF 3-PHASE INDUCTION MOTOR USING PSCAD

This paper is designed to protect an Induction Motor from different types of abnormalities. Providing protection for motors is very important in industries, power plants etc. such that production is not hampered owing to failure of any motor. Purpose of motor protection is to limit the effect of disturbances and stress factors to a safe level. If a motor failure takes place, the protection is needed to disconnect the motor from the supply network in due time. Here we have described different abnormal conditions in three phase induction motors and designed a protective scheme to protect it from different abnormalities. We have also described the method which shows how to set electromagnetic relay for large motor and also described the same method in case of numerical relay. Here we have shown one of the faulty condition with the help of PSCAD (student version).

STRUCTURE AND TECHNOLOGY OF THE NUMERICAL RELAY PROTECTION IN THE POWER SYSTEMS

Abstract. Numerical relays permit development of new functions as well as development of adaptive relaying schemes. Digital relays, providing flexibility to the user and to electromagnetic and static relays are superior advanced microprocessors, and economic empowerment, increased attention to the supply and use of microprocessor-based protective relays were. This paper introduces the technology of power system relay protection. Refers to the generation of protective relays and upgrade them and eventually to relay the new generation of digital signal processing technology deals.

Quality Analysis and Consistency Design of Electromagnetic Device Based on Approximation Model

The consistency problem caused by the uncertainties in manufacturing process is a significant factor influencing the quality of electromagnetic device (EMD). The foundation of quality analysis and consistency optimization is the substantial calculation for the input-output characteristics of the product. As for EMD, the interaction of electricity, magnetism (permanent magnetism), and dynamics make the calculation quite complicated. At present, finite-element method (FEM) is a common method for calculating the output characteristics of EMD. However, FEM takes too much time for calculating, it is difficult to be applied for the quality analysis and consistency design of EMD that requires substantial calculation. In this paper, a new approach for the quality analysis and consistency design of EMD based on the approximate model has been proposed. First, the approximate model for calculating the EMD output characteristics is established on the basis of FEM simulation results. Second, using the approximate model, the quality analysis of batch products is conducted with Monte Carlo method. Finally, the optimal design for consistency is carried out with robust tolerance design method. The effectiveness of the method proposed in this paper is verified by the case study of a certain type of electromagnetic relay with permanent magnet.

A type of 2D magnetic equivalent circuit framework of permanent magnet for magnetic system in AEMR

Modeling of permanent magnet (PM) is very important in the process of electromagnetic system calculation of aerospace electromagnetic relay (AEMR). In traditional analytical calculation, PM is often equivalent to a lumped parameter model of one magnetic resistance and one magnetic potential, but great error is often caused for the inner differences of PM; based on the conception of flux tube, a type of 2D magnetic equivalent circuit framework of permanent magnet model (2D MECF) is established; the element is defined, the relationship between elements is deduced, and solution procedure as well as verification condition of this model is given; by a case study of the electromagnetic system of a certain type of AEMR, the electromagnetic system calculation model is established based on 2D MECF and the attractive force at different rotation angles is calculated; the proposed method is compared with the traditional lumped parameter model and finite element method (FEM); for some types of electromagnetic systems with symmetrical structure, 2D MECF proves to be of acceptable accuracy and high calculation speed which fit the requirement of robust design for AEMR.

A Pilot Self-Sustaining Time Delay Safe Switch

We designed a type of pilot-operated self-sustaining time delay power on/off circuit which consists of a duplex switch, time delay circuit and a dual-coil, dual-contact electromagnetic logic control relay. We also depicted a dual-coil, dual-contact electromagnetic relay logic control circuit diagram dedicated to this design. Structures and specific couplings of the circuit were presented and analyzed. Functional analysis was also carried out for a variety of work processes performed on the circuit at static or dynamic state, and the results showed that the circuit, in addition to fulfilling its primary function for time delay shutdown of the main circuit, is also capable of automatically powering-off the control circuit and the control power supply when the device is left unattended. This design greatly meets the needs of current time delay control technology, and thus has a great commercial potential.

A universal driver for vibration free operation of mechanical shutters

We report design of an universal driver circuit for efficient operation of home made mechanical shutters using electromagnetic relay, dc motor (DCM) and laptop hard disc drive (HDD). The driver puts out high, medium and low currents for overcoming the inertia, fast sweeping and soft landing of the shutters. All the shutters operate with significantly reduced mechanical vibrations and hence produce low levels of acoustic noise. The electromagnetic relay, dc motor and HDD shutters operate at sweeping speeds 1.7(2)m/s, 1.6(2)m/s and 2.8(3)m/s, respectively.

A Prognostic Framework For Electromagnetic Relay Contacts

Electromagnetic relays provide a well proven solution to switching loads in a variety of applications. However, relays are known for their limited reliability due to mechanical wear of internal switching elements, essentially the life of the relay may be determined by the life of the contacts. Failure to trip, spurious tripping and contact welding, can in critical applications such as control systems in avionics and signaling for rail networks, cause significant costs due to downtime as well as safety implications. Prognostics provides a way to assess the remaining useful life of an electromagnetic relay based on its current state of health.In this paper, the cause of failure and degradation for electromagnetic relays used in avionic power controllers are examined. A first principle model of an electromagnetic relay, including contact wear is proposed. The degradation observations and measurements form the basis for developing a model based remaining useful life prediction algorithm. Our overall aim is to derive a simple but accurate model of the relays contact degradation, and provide prediction of performance changes within the component.

Design and characterization of a thermally actuated latching MEMS switch for telecommunication applications

This paper describes the design and characterization of a thermal actuator and a latching MEMS switch, using the actuator. The proposed MEMS switch is designed for applications in telecommunication, in which it could be an alternative solution for the now existing electromagnetic relays for automated distribution frames. A MEMS-based switching matrix could be a very attractive solution as it can be made very compact, cost-effective, reliable and scalable. The actuators used in the switch use a polysilicon heater, which heats up the structure and causes deflection. The actuators were fabricated by using MetalMUMPs technology and measured results showed good agreement with the finite element results. Using these actuators, latching switches were also successfully fabricated. No energy is needed to stay in the open or closed state of the switch, which saves energy, but also keeps the interconnection state of the switching matrix in case of a power failure. The time- and current-dependent switch resistance was also measured and remained below 1.52 Ω after 105 latching cycles. The proposed switches could be very useful in a switching matrix for an automated distribution frame.

Prototype of Compact Flexural Fatigue Testing Machine

The purpose of this project is to build a prototype of compact flexural fatigue testing machine and to strive for an easy working-environment as required by the users besides cutting the cost of the machining. This particular project is about to build the prototype of compact flexural fatigue testing machine in compact mode. In this project, the prototype will be functioning 60% similar to the real fatigue machine which is Dynamic Fatigue Testing Machine (INSTRON) due to timer counter, frequency and load applied. But the new invention is this prototype was using the concept of electromagnetic force relay that will apply to the specimen using the application of basic electronics. The motion sensor also being applied to this prototype to achieve accurate results when the specimen breaks up after undergoes a fatigue failure.

Research of Storage Failure Mechanism on JZX-10M Aeronautic Sealed Relay

This paper attempts to study JZX-10M sealed electromagnetic relays storage failure mechanism through accelerated test. And take internal gas analysis, the relay detector, leak rate measurement, EDS analysis as auxiliary measuring means, after the necessary testing and post-analysis, found that the contact resistance rise because the film-forming gas contamination on internal contact surface. EDS observations of the surface of the carbon atom deposition are not obvious, this paper analyzes the results.

Microcontroller Based Under/Over Frequency Relay for Power System Protection

This paper investigates the frequency fluctuation in power system and protect the power system from its harmful effects. Therefore we design a Microcontroller Based Under/Over Frequency Relay. In this paper we use microcontroller AT89S52 for protecting the power system from the problem of frequency fluctuation. When frequency goes below or above from desired value then electromagnetic relay trip and isolate our power system from its harmful effect. Electromechanical protective relays operate by either magnetic attraction, or magnetic induction. Frequency Variation also decrease the life of the equipment and directly affect the overall production of the plant.

Failure Mechanism Analysis of Electromagnetic Relay under Mechanical Impact

The aim was to analyze failure mechanism of electromagnetic relay caused by mechanical impact. The principle of electromagnetic relays was studied and the effect of mechanical impact on electromagnetic relays was analyzed in this paper. Based on the established magnetic circuit model, the relationship of the magnetic field strength, the electromagnetic attraction and the impact damage degree was studied. Then, the damage intensity of mechanical impact on magnetic circuit was decided. Afterwards, the structure of electromagnetic relays was improved, and the mechanical impact simulation was studied by ANSYS. The results show that the uncontrollability of electromagnetic relay is mainly caused by air gap, which is aroused by mechanical impact; in addition, the size of air gap is inversely proportional to electromagnetic attraction force. Moreover, the improved structure of relays can increase impact resistance and broaden the scope of engineering application of electromagnetic relay.

Application of Frequency Conversion Technology in the Constant Pressure Water Supply System

In order to solve the problem that the management of water-supply operation is still backward and the phenomenon of water resources wasting is exceedingly serious, this paper introduce some advanced technologies such as computer, frequency transformer, programmable logical controller (PLC) and so on into water-supply network, the constant pressure water supply system is devised to achieve the variable-frequency speed control by making use of the electric controlling system composed of S7-200PLC, MM440 frequency transformer, miniature circuit breaker, AC contactor, thermal relay, DC power supply, miniature electro-magnetic relay, sorts of indicator lights and host command devices.

An Improved Weighted Average Method for Test Data Analysis of Electronic Components

Electronic components are the basis of electronic equipment, and their reliability and lifetime have a direct impact on the work efficiency of the whole electric system. In fact, the test data on life characteristic parameters (LCP) of electronic components present random fluctuations because of the existence of some disturbing factors in the process of life test. This will bring great obstacles to the study on the rules of LCP, the reliability and life forecasting of electronic components. In order to solve these problems, this paper proposes a method of the determination of weight coefficients and an improved weighted average algorithm to reveal the rules of LCP. In the improved weighted average algorithm, the latest data is constantly introduced while the oldest data is removed. By an example of contact bounce time on electromagnetic relay, the application verification has been carried out on the above-stated method in the paper. The results show that the method is effective and feasible.

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.

Influence of Harmonic on the Protections of Capacitor Bank

This paper introduces the capacitor bank equipped with overvoltage protection and overcurrent protection. Then with a group of capacitor for reactive power compensation as the research object, this paper analyses the influence of harmonic to the two protection modes when the electromagnetic, static or microcomputer relay are applied.

A Tester for Protective Relays of High Power Electrical-Motors

In this paper the operation and construction of a protective relay tester based on the PCs will be studied. Since this tester has computer, it is capable of programming to test different types of protective relays. On the other hand, because of its 3 phases voltage and current outputs, the hardware of this device makes it possible to test different types of electromagnetic, static, and digital relays. One of the main characteristics of this device is to real time reconstruction of the signals obtained in transient states. Other capabilities of this device include the ability of sending digital signals to the relay in adjustable times, which is widely used including in testing protective plans with telecommunication signals. At the end of paper, the results of some sample tests will be presented that show the good performance using this device in the test of different types of relays.