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In the optimum design of AC contactors, it is important to analyze the dynamic behavior. Moreover, movable contact and core bounces have remarkable effect on the lifetime of contactors. According to a kind of intelligent contactor with feedback mechanism, this paper builds two different sets of periodically inter-transferred equations. The equations describe the coupling of the electric circuit, electromagnetic...
This work attempts to quantify the effect of repeated initial connector insertions and roughness on electrical contact resistance. Experimental measurements show that the electrical contact resistance increases measurably with repeated insertions. They also show that with repeated insertions the connector spring is plastically deformed, thus causing the force closing the contact across the surfaces...
The resistance and capacitance of a typical multi-point contact interface has been used to assess the impact on high frequency signal integrity. In the past it was shown how fully degraded interfaces can still provide acceptable performance for high data rate signal transfers. In the case of fully degraded contacts, signals were shown to transfer by capacitive coupling and wave propagation. This paper...
Up to now, it is difficult to test the inner temperatures of sealed electromagnetic relays. In this paper, the temperature distribution of a sealed electromagnetic relay is obtained by using 3-D finite element analysis. The quality of thermal simulation results depends on the accuracy of both the modeled heat sources and heat sinks. Due to the high performance requirements of sealed electromagnetic...
In the optimization design of contact system for the air circuit breaker (ACB), it is important to calculate the short-time withstand current. Introducing the contact bridges to describe contact spots between movable and fixed contacts, transient analysis is carried out by coupling electromagnetic field and thermal field to parallel contact systems, where nonlinear of ferromagnetic splitter plates...
In a switching circuit with an inductive load, arc discharge and surge generated during a breaking operation are big problems. We proposed an electric method for arc discharge suppression using a timely controlled transient current switch and a capacitor arranged in parallel to the energizing switch. In this paper, we propose an improvement. We replaced the capacitor with two capacitors. One to suppress...
The juxtaposition of low-cost dual inline memory module (DIMM) connectors in highly reliable servers has created a difficult reliability, availability, and serviceability conundrum: the connector cost must be low enough to allow hundreds of sockets to be used per system, while at the same time, the system-level reliability must be high enough to prevent connector-related memory failures. This paper...
Speed separation in switches and relays is a fundamental parameter to improve breaking devices performances by reducing extinction gap and arc duration. It is commonly admitted, that with resistive load, high speed separation produces lower arc duration and keeps constant extinction gap, whereas with inductive load, the extinction gap is enlarged. The objective of this paper is to minimize the gap...
Break arcs occurring between electrical contacts are observed in DC42V resistive circuit using a high-speed camera. Materials of contact pairs are Ag or Ag/ZnO. The break current is 10A. Spectroscopic images are obtained using the high-speed camera with optical band pass filters. The filters are attached on the lens to observe only the Agl 521 nm or ZnI 481 nm spectrum images, respectively. The time...
Contacts, switching DC loads, can create material transfer pip and crater formations which may cause non opening faults due to interlocking. Both, the material transfer formation and the capability to open the contacts at pronounced material transfer, are affected by the design parameters of the contact system. Since the decoupling of these two phenomena cannot be carried out in experimental investigations,...
Recently characteristics required of automobiles have been diversified, and from the electric/electronic points of view, the changes of automobiles are a wide range of electronization flow of control and changes of power source of automobiles represented by electric automobiles and the transmission system. Considering these, the connector, one of the network parts of an automobile to shoulder the...
Short-circuits in electrical networks come along with severe mechanical and thermal stresses not only to loads and systems, but also to the installed protection devices. Combined analytical simulations have been performed for analyzing and optimizing the behavior of low-voltage circuit-breakers. Especially circuit-breakers with electronic tripping units have been scrutinized.
Experiments were performed with vacuum interrupters containing Cu-Cr (25 wt%) and W-Cu (10 wt%) contacts. The vacuum interrupters were placed in a spring mechanism, which was placed in a tuned, capacitor bank electrical test circuit. The capacitor bank was charged to 25 kV, which allowed a symmetrical fault current of 50 kA (peak) at 30 Hz. As the vacuum interrupter's contacts closed a prestrike arc...
Pressure rise of the gas due to high current arc in the arc chamber of molded case circuit breaker (MCCB) may accelerate the arc movement and improve the corresponding interruption performance. However, this pressure rise may result in a heavy stress on the enclosure of the arc chamber. The paper is devoted to calculate the pressure rise and analyze its characteristics. Based on thermodynamics and...
Properties of glowing connections for a variety of electrically conductive materials are presented. The properties investigated include voltage waveforms, rms voltage with current and the propensity to initiate glowing. This was done using materials that may be used in residential electrical wiring. The materials and combinations of materials investigated were copper, brass, phosphorous bronze, steel,...
Characteristics of conductive elastomer which is composed of silicone rubber and dispersed carbon black particles shows conductive and elastic properties in one simple material. This material has been widely applied to contacts of switches and connectors of a liquid crystal panels. However, since surface state of the contact is very soft, it is difficult to remove contaminant films of contaminated...
Silver/tungsten powder metal electric contacts are used in circuit breakers because of their combination of high conductivity from silver, and high melting temperature from tungsten. In operations of the circuit breaker, switching arcs erode and oxidize the contact surface to create a high resistance layer that can lead to high temperature at the contacts. This arc erosion product is usually a mixture...
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