The main factor determining for both friction and contact resistance is the true contact area in the contact interface. Contact resistance depends on the size of the true contact area and contaminant films interposed between the contact areas of the interface. Moreover, friction force also depends on the true contact area. In particular, the formation of metallic junctions in the true contact area strongly effects the friction force. Therefore, since both electrical contact and friction force are related to the size of the true contact area, the contact resistance and friction force are considered to be interrelated through true contact areas. For electromechanical devices with sliding contacts such as connector and sliding switches, the contact resistance and friction are important characteristics. In order to obtain low contact resistance, contact load should be higher, but the friction force increases. These are opposite-side problems. In this study, as the contact resistance and friction occur in the same true contact area, the relationship between the contact resistance and friction was expressed in an equation. Moreover, this relationship was examined experimentally on a variety of contact surfaces under different surface conditions.

In this paper, the separation of heat generation and heat transfer related to temperature rise of silver palladium contact was investigated experimentally in order to predict the temperature rise of contact by the use conditions such as voltage range between 25 to 40 V, current range between 3.2 to 5.0 A and silver palladium alloy (AgPd) materials. Firstly, relationship between temperature rise of contact and supply power was discussed. The effects of heat generation and heat transfer on temperature rise were separated and quantified by least squares method. Secondly, effects of durations and integral powers of bridge and arc on temperature rise were also discussed by changing supply power. Results show that the integral power of the bridge increases when supply power increases. As the supply power increases, integral power of arc also increases. The temperature rise is dominated by integral power of bridge. Remarkable difference of bridge duration can not be seen in the five materials (AgPd₃₀, AgPd₄₀, AgPd₅₀, AgPd₇₀ and Pd). The supply power is increased, arc duration gets longer. As weight percent of Pd content increases, the effect of supply power on arc duration becomes larger. Consequently, the integral power of arc increases. This study is a basic consideration to realize methods predicting temperature rise of contact.

The mechanism of dark bridge formed with very slow contact separating speed was empirically shown with some discussions from the experimental results which the authors have obtained by using the cantilever system for controlling contact gap. By analyzing the obtained results, we will assume some concept of formation mechanism of dark bridge. Since the thermal effect is inevitable in the bridge formation, this will be inferred from two points; one is the a-spot change at initial state of bridge forming, and another one is the thermal expansion due to bridge current that affects the shape of bridge. This paper will show from these two points the conceptual bridge formation mechanism in case of non-melting state of contact bridge which is called here dark bridge.

Breaking arcs are generated between a pair of Cu electrical contacts in a DC 42 V/10.5 A circuit, and the arc voltage, the arc current and the time-resolved arc spectral intensities near contact surfaces are simultaneously measured. The arc temperature is calculated from some spectral intensities emitted from Cu neutral atoms using the Boltzmann plot method. The arc temperatures near the cathode and anode surfaces are measured, and the following experimental results were obtained. (1) Time evolutions of the spectral intensities and the calculated arc temperature have similar characteristics. (2) The arc temperature near the anode surface is higher than that near the cathode surface, and the temperature fluctuation near the anode surface is larger than that near the cathode. (3) Just before arc extinction, the arc temperature near the cathode surface is almost constant for many breaking operations but the arc temperature near the anode surface varies.

Breaking arcs occurring between silver electrical contacts are observed in DC42 V resistive circuit using a high-speed camera. The motion and current densities of the cathode and anode spot regions are investigated for different interrupt currents (I=7 A, 10 A and 14 A). Results indicate that the arc length at which the motion of arc spots becomes stable depends on the interrupt current, and the current densities of the cathode spot region are almost constant immediately before arc extinction for each interrupt current.

DC motors are indispensable to improve the automotive functions. Recently, 70-100 motors are installed on luxury cars and this number is increasing year by year. With the recent demand for improved fuel economy and better equipment layout, the improvement of the motor's efficiency and the minimization of the motor size are the key to enhancing the competitive edge of the products. Adopting the high-density coil is an effective method for that, but it is accompanied by the commutation inductance rise which causes the commutation arc increase. The increase of commutation arc decreases motor life, because it causes the rise of brush/commutator wear. This report describes an arc-reducing effect obtained when capacitors are built into a commutation circuit for the purpose of reducing arcing under high commutation inductance conditions. The results of an evaluation using a equivalent commutation circuit and carbon brush/carbon flat-commutator showed that although a commutation circuit with built-in capacitor generated the same arc energy as a commutation circuit without a capacitor above a certain value of residual current, it displayed an excellent arc-reducing effect below that value of residual current.

Arc occurrence rates were measured for Ag contacts in DC resistive and inductive load circuits. In inductive load conditions, arc occurrence rates in general came close to 100% at around 0.4 A, the conventional minimum arc current level of Ag. In resistive load conditions, the similar results were obtained with 30 V, while arc occurrence rates close to 50% were still obtained at around 0.4 A with 14 V and 10 V. Careful attention should be paid to the term "minimum arc current" to avoid misinterpretation thereof.

At present, during the design of sealed electromagnetic relay, the tolerances of design parameters are given with experience. The designer can't provide quantificational reliability index, and the blindness of tolerance distribution also causes unnecessary increase of machining cost. According to the study of electromagnetic force and spring force characteristics of a certain sealed electromagnetic relay with polarized magnetic system, this paper analyzed the influence of main design parameters' tolerances to the tolerance bands of electromagnetic force and spring force characteristics and achieved the strong correlative factors (viz. design parameters) that have obvious effect on tolerance bands of electromagnetic force and spring force characteristics. Then based on the calculation of reliability, the tolerance distribution method of key design parameters was given. This method not only can make the designed product satisfy requirement of reliability, but also reduce the machining cost.

A method which uses the moving time and the over travel time of contact to discover the characteristics of contact and the reliability of aerospace relay is proposed. The Gauss-Newton method and its improved form (Macalto method) are used to identify the nonlinear mathematical model of the parameter during armature initial moving period, which is from the coil is energized at a rated voltage to the moment the armature begins to move. The validity of the method is verified by results of actual experiments and analysis.

Vibration characteristic of electromagnetic relay (EMR), including modal and frequency response are important for increasing operational reliability in mechanical environment. The switching contact system, as function execution component of EMR, is the important parts in this product. This paper presents a dynamic model of contact system by introducing Hertz contact theory, and discusses weakly nonlinear oscillation character. Quasilinear simulation analysis using by finite element analyzing software-NASTRAN is investigated. The factors affecting contact vibration characteristic are determined. Finally, theory analysis and simulation results are verified by the vibration test. The model starts from a typical contact system of EMR, but the approach can be applied to other switching electro-mechanical devices.

We proposed a method for suppressing arc ignition in mechanical contact devices using a transient current switch and a capacitor. We applied the method to conventional reed switches. For the electric circuit analysis, we clarified the momentary voltage-current characteristics at breaking operation of reed switches by FEM analysis. We could also estimate the capacitance of the contact electrodes at the metal bridge rupture by FEM analysis, and would derive the non-arcing condition using SPICE simulation. The suitable capacitor value in the transient current circuit for arc ignition suppression would be depend on the load impedance, the power supply, the time depending contact resistance R(t)s, the contact capacitance, and the minimum arc voltage and current.

To one double-breaker model, experimental investigation on blow open force was carried out. It demonstrates that the ratio between the emerging blow open force and arc power F_B/ui decreases with the arcing time, the contact gap has less effect on F_B/ui, and the characteristics of the blow open force are similar when the peak value of the short circuit current is beyond 4 kA. Then, according to the experimental data and conclusions, considering the influence of blow open force, the interruption process of molded case circuit breakers (MCCBs) was investigated. It demonstrates the blow open force has significant influence on interruption process and the proposed method is effective to evaluate new design of MCCBs.

In the optimum design of contactors, it is important to analyze the dynamic behaviors. In this paper, it proposes a new computational approach for analyzing dynamic characteristic of the energy-saving and bouncing-reducing double-coil contactor. According to the contactor's unique characteristic that it has two transferable coils, the paper builds two different sets of equations. One describes the period before the transfer position, and the other describes the period after the transfer position. The equations deal with the electrical circuit, electromagnetic field that can be calculated by using 3-D finite element method and mechanical system considering the influence of friction. The validity of the proposed method is confirmed by experiment. Finally, the paper gives an optimum design for the transfer position of the two coils. The result of the optimum design reduces both of the first and the second bounces of the movable contact.

Two dimensional optical fiber measurement system is used to investigate experimentally the arc motion and reignition with four different configurations of quenching chamber in an AC contactor. It demonstrates that the splitter plate arrangement has significant effect on the arc motion in arc quenching chamber, and fixing arc runner in the first and last splitter plates benefits to arc motion, and increase the dielectric recovery strength. The results are very useful to design the quenching chamber in AC contactor with high performance.

Anode activity in vacuum arc plays a very important role in both characteristics of vacuum arc and the interruption capacity of vacuum interrupters. In this paper, the transient thermal processes of anode in vacuum arc in a half of arc current cycle with frequency of 50 Hz are simulated by finite element analysis software, ANSYS. Some important phenomena of anode, e.g., the melt and solidification, mass loss due to evaporation, are investigated.

A new type of permanent magnet actuator driven by electromagnetic repulsive force in breaking course and electromagnetic attraction force during closing course is presented in this paper, and the static and dynamic characteristics for contactor with this new type actuator are mainly focused on by simulation and experiment simultaneously. Firstly, the static electromagnetic attraction force in closing course and electromagnetic repulsive force in breaking course are studied by FEM simulation and experiment. Secondly, by coupling of the electrical and mechanical differential equations, the dynamic electromagnetic attraction force in closing course and dynamic electromagnetic repulsive force in breaking course are obtained respectively. Thirdly, by constructing the mechanical model of contact system and permanent magnet actuator, the displacements of moving contact and moving core while both contactors' closing and breaking are obtained by simulation and experimental study. It is indicated that simulation results coincide well with that of experiment.

To provide basic considerations for the realization of methods for predicting the electromagnetic (EM) radiation from a printed circuit board (PCB) with plural signal traces driven in the even-mode, the characteristics of the EM radiation resulting from two signal traces on a PCB are investigated experimentally and by numerical modeling. First, the frequency responses of common-mode (CM) current and far-electric field as electromagnetic interference (EMI) are discussed. As the two traces are moved closer to the PCB edge, CM current and far-electric field increase. The frequency responses in the two signal trace case can be identified using insights gained from the single trace case. Second, to understand the details of the increase in CM current, the distribution of the current density on the ground plane is calculated and discussed. Although crosstalk ensues, the rule for PCB design is to keep two high-speed traces on the interior of the PCB whenever possible, from the point of view of EM radiation. Finally, an empirical formula to quantify the relationship between the positions of two traces and CM current is provided and discussed by comparing four different models. Results calculated with the empirical formula and finite-difference time-domain (FDTD) modeling are in good agreement, which indicates the empirical formula may be useful for developing EMI design guidelines.

To clarify the transmission characteristics and near magnetic field on the angle pattern for the parallel transmission lines, the authors investigate how influence the angled pattern on the transmission lines by experiment and calculation. The angled patterns on the transmission lines are straight, right angle and curve. It shows that the suppression of EMI radiation at the angled pattern on the parallel transmission lines of the magnetic head is essential. In addition, it is suggested that angle pattern might be one of cause for the signal distortion and specific EMI radiation at high frequency.

We have developed an optical connector assembly method that allows the rapid on-site installation of an optical connector. To simplify this on-site assembly process we fabricated built-in parts that enable us to install the optical connector using pre-assembled optical connector parts. Moreover, we have established an advanced method for applying a solidifying agent that adheres to the inner wall of a ferrule flange. With our assembly method, we can complete on-site optical connector installation, other than the polishing process, in two steps, namely bonding agent application and fiber insertion.

Field assembly of optical connectors is demanded because of the wide use of optical fiber in telecommunications systems. We propose a new assembling techniques that enable us to assemble connectors anywhere quickly and cost effectively. The key points are an adhesive technique and a polishing technique. In this report, we focus mainly on our a new polishing machine, which is suitable for optical connector ends machining on-site. The machine which is small and light weight can finish optical connector ends easily in a short time with enough low cost.

In modern CMOS digital design, the noise immunity has come to have an almost equal importance to the power consumption. In the last decade, many low power design schemes have been presented. However, no one can simply judge which one is the best from the noise immunity point of view. In this paper, we investigate the noise immunity of the static CMOS low power design schemes in terms of logic and delay errors caused by different kinds of noise existing in the static CMOS digital circuits. To fulfill the aims of the paper, first a model representing the different sources of noise in deep submicron design is presented. Then the model is applied to the most famous low power design schemes to find out the most robust one with regard to noise. Our results show the advantages of the dual threshold voltage scheme over other schemes from the noise immunity point of view. Moreover, it indicates that noise should be carefully taken into account when designing low power circuits; otherwise circuit performance would be unexpected. The study is carried out on three circuits; each is designed in five different schemes. The analysis is done using HSPICE, assuming 0.18 µm CMOS technology.

A highly integrated monolithic Multi-Service Transport Platform (MSTP) ASIC MSEOSX8-6 incorporating more than 26M transistors has been fabricated with 0.18 µm CMOS technology. The chip is a powerful monolithic MSTP ASIC that supports RPR applications and serves as a generic building block for MSTP network. To accelerate the chip design, we devise a novel methodology called Embedded Reduced Self-Tester (ERST), which integrates the reduced self-tester structure into the chip to shorten the duration of dynamic simulation. Moreover, we divide the design into 12 smaller Hierarchical Layout Blocks (HLB) to enable parallel layout. Resultantly, the whole design has been completed in 5 months, which saves at least 80% of the design cycle in all.

This investigation proposes a modified equivalent circuit of single complementary split-ring resonator (CSRR) in planar transmission media and a dual-mode ring bandpass filter (BPF) that uses periodic CSRRs to suppress the spurious response. The proposed modified equivalent circuit consists of lumped elements that can be easily extracted from the measured S parameters. The proposed dual-mode ring BPF has exhibits a wide stopband characteristic owing to the bandgap resonant characteristic of CSRRs in the harmonic frequency of the dual-mode ring BPF. Good agreement with EM simulation and measurement is demonstrated.

Capless high electron mobility transistors (HEMTs) were fabricated and their DC and RF performances were characterized. Capless HEMTs did not have highly doped InGaAs cap layer so that gate recess process was not required in the fabrication of capless HEMTs. The electrical performances of the capless HEMTs were compared with those of conventional HEMTs with highly doped InGaAs cap layer. A typical 0.2 µm capless HEMT exhibited a maximum transconductance of 805 mS/mm, a threshold voltage of -0.5 V, and a unity current gain cut-off frequency (f_T) of 137 GHz. Capless HEMTs exhibited improved device uniformity compared with conventional HEMTs fabricated by wet gate recess technology.