Contact Resistance Of Connectors Research Articles

Electromagnetic interference shielding performance calculate model for double layer shielded cable connector in EV

Due to the high voltage and high current working characteristics of EV driving system, strong electromagnetic interference is formed in the working process, and the shielding effectiveness of the high-voltage connector assembly connecting each part of the driving system is directly related to the level of its electromagnetic interference emission. The high-voltage connector is usually made by triaxial method. However, due to the influence of sample coupling length and cutoff frequency, the triaxial method is prone to produce a region of more than 25 MHz, resulting in test failure. Therefore, modeling analysis of the shielding effectiveness of the connector assembly in the early stage is crucial for the final development of a connector assembly with good shielding effectiveness. In this paper, an analytical optimization model named ZTD-Demoulin is proposed to calculate the transfer impedance value of the dynamic shielded wire (double-layer shielded) of the electric vehicle. The model takes into account the influence of the double-layer shielded cable (braided-belt and aluminum foil) on the DC resistance and small-hole inductance of the shielding layer, and analyzes the transfer impedance value which presents the shielding effectiveness of the connector assembly. Based on the double-layer shield optimization model, an optimization model of high-voltage connector assembly is established. This established model takes into account the influence of connector contact resistance and inductance value. Comparison between the triaxial coaxial method and the established model found that when Kconnector = 6Kcable, the fitting effect of the model was the best and the transfer impedance value above 25 MHz could be predicted.

Electrical Contact Resistance of Connector Response to Mechanical Vibration Environment

Contact resistance is an important barometer for service life and reliability of electrical connectors, which are widely used in electrical and electronic system. Long and harsh mechanical vibration stress would result in the function failure of electrical contact. In this article, the electrical contact resistance (ECR) of a typical connector is accurately recorded in real time with the four-wire method under mechanical vibration environment. Furthermore, the relationship between the ECR and vibration stress (including frequency and acceleration) is investigated explicitly. To better understand the physical mechanism of the ECR fluctuation and degradation, the vibration transmission path and associated dynamic response model of the connector are built. Finally, the main influencing factors on the ECR under mechanical vibration stress are summarized systematically.

Dynamic Performance of Electrical Connector Contact Resistance and Intermittent Fault Under Vibration

Static electrical contact resistance (ECR) has been well researched. To investigate the dynamic performance of electrical connector under vibration, a test apparatus is built to measure the ECR with high precision. The ECRs are tiny and suffer from noise. Therefore, a wavelet packet transform-based denoising method is proposed. This method can filter noise with frequency components ranging from low to high. The dynamic characteristics of ECR are presented after an analysis of the measured results. Moreover, the connector intermittent fault (IF) performance under vibration is characterized and analyzed. Finally, an ECR model for rough surfaces under vibration is proposed, based on which the discovered laws are theoretically analyzed. The detected dynamic characteristic of ECR and IF can support an online diagnosis of connectors in further research.

Study of Contact Resistance in Connectors With Physical Simulation Using Nanofabrication

The contact resistance of electrical contacts in connectors consists of constriction resistance that results from the constriction of current flow and the film resistance of the high-resistivity material between the two electrodes. The constriction resistance depends on the number of contact points and their sizes. In the case of a simplified single-point contact, the constriction resistance can be calculated analytically; however, this is not the case for real contact. To establish a relationship between the physical structure of an electrical contact and its constriction resistance, samples that represent the contact structure were fabricated on a Si-chip for measuring the constriction resistance.

Combined effects of fretting and pollutant particles on the contact resistance of the electrical connectors

Usually, when electrical connectors operate in vibration environments, fretting will be produced at the contact interfaces. In addition, serious environmental pollution particles will affect contact resistance of the connectors. The fretting will worsen the reliability of connectors with the pollutant particles. The combined effects of fretting and quartz particles on the contact resistance of the gold plating connectors are studied with a fretting test system. The results show that the frequencies have obvious effect on the contact resistance. The higher the frequency, the higher the contact resistance is. The quartz particles cause serious wear of gold plating, which make the nickel and copper layer exposed quickly to increase the contact resistance. Especially in high humidity environments, water supply certain adhesion function and make quartz particles easy to insert or cover the contact surfaces, and even cause opening resistance.

Development of a high hertz-stress contact for conventional batch production using a unique scribing technology

Gradually the electronic devices are getting more compact dimension with respect to the width and thickness. As a result, the contacts are becoming thinner and which leads the contact to be loose and unstable contact. In comercial stamping methode, connector tip diameter should be more than 300μm due to its size limitation. Consequently, the connector contact resistance is becoming higher due to weak contact force. To overcome this problem there were few more basic research using MEMS and Electro Fine Forming (EFF) technology to make high Hertz-Stress Contact (5μm) due to the limitation in the commercial stamping process and the result was in satisfactory level. However, since the MEMS and EFF fabrication is costly therefore, a new method is introduced in this paper using the commercial Phosphor Bronze stamping method to reduce the production cost. Moreover, scribing method is used to make tip on the contact. Accordingly, more compact fine pitch contact is successfully fabricated and tested with 5μm High Hertz Stress without using the MEMS and EFF technology. Hence the manufactured contact resistance becomes less than 20mΩ ±5mΩ.

Testing of Large Lead Stationary Batteries

This paper presents background information on capacity and qualification testing of lead batteries and provides an analysis of the measurement of connector contact resistance. Due to parallel resistive paths the measured resistance can be from 36 to 95 percent lower than the actual resistance.