Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489687
M. Hasegawa, K. Niizuma, H. Mizukoshi, S. Fujii, K. Sawa
Arc discharge between electrodes of electromechanical relays and mechanical switches often causes contact surface damage through material transfer and arc erosion. Especially, material transfer sometimes occurs even with a very small load current such as DC50 to 100 mA, which is quite a bit smaller than the minimum arc current value of each contact material. In this paper, material transfer characteristic of silver contacts installed in telecommunication relays were studied with a scanning laser microscope under various resistive load conditions. The relation between electrical load conditions (load current and power supply voltage) and contact surface configuration caused by material transfer (craters and pips) was studied. It is confirmed that material transfer occurs by anode arcs even with the load condition of DC10 V-50 mA, which might be considered too light to have an arc discharge. The tested samples can be categorized into two groups; material transfer phase and arc erosion phase. Transition from transfer phase to erosion phase is believed to occur and is related to the contact activation process. The results also indicate that load current has an influence on the material transfer phenomena and power supply voltage is related to the arc erosion phenomena.
{"title":"Material transfer characteristic of silver contacts under resistive DC load conditions","authors":"M. Hasegawa, K. Niizuma, H. Mizukoshi, S. Fujii, K. Sawa","doi":"10.1109/HOLM.1993.489687","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489687","url":null,"abstract":"Arc discharge between electrodes of electromechanical relays and mechanical switches often causes contact surface damage through material transfer and arc erosion. Especially, material transfer sometimes occurs even with a very small load current such as DC50 to 100 mA, which is quite a bit smaller than the minimum arc current value of each contact material. In this paper, material transfer characteristic of silver contacts installed in telecommunication relays were studied with a scanning laser microscope under various resistive load conditions. The relation between electrical load conditions (load current and power supply voltage) and contact surface configuration caused by material transfer (craters and pips) was studied. It is confirmed that material transfer occurs by anode arcs even with the load condition of DC10 V-50 mA, which might be considered too light to have an arc discharge. The tested samples can be categorized into two groups; material transfer phase and arc erosion phase. Transition from transfer phase to erosion phase is believed to occur and is related to the contact activation process. The results also indicate that load current has an influence on the material transfer phenomena and power supply voltage is related to the arc erosion phenomena.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75277333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489686
T. Tamai, M. Aramata
The effect of silicone vapour concentration on the contact failure was examined by using micro relays and motor brush-slip ring (commutator) contacts. A minimum limiting concentration level which does not affect contact reliability was found. This limiting level was 10 ppm (0.13 mg/1). Validity of the limiting level was confirmed by the relationships among concentration, temperature, SiO/sub 2/ film thickness and contact resistance. Furthermore, the effect of the degree of silicone polymerization on the limiting concentration was derived by an empirical formula. These results were confirmed by the contact failure data due to the silicone contamination.
{"title":"Safe levels of silicone contamination for electrical contact","authors":"T. Tamai, M. Aramata","doi":"10.1109/HOLM.1993.489686","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489686","url":null,"abstract":"The effect of silicone vapour concentration on the contact failure was examined by using micro relays and motor brush-slip ring (commutator) contacts. A minimum limiting concentration level which does not affect contact reliability was found. This limiting level was 10 ppm (0.13 mg/1). Validity of the limiting level was confirmed by the relationships among concentration, temperature, SiO/sub 2/ film thickness and contact resistance. Furthermore, the effect of the degree of silicone polymerization on the limiting concentration was derived by an empirical formula. These results were confirmed by the contact failure data due to the silicone contamination.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90688091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489691
K. Hinohara, K. Nakamura, T. Kobayashi, T. Miyata
Reed switches have been used in various fields of application due to excellent reliability and compactness. The progress of electronics is leading to increasing demand for enhanced functions of the reed switch. One such demand is high breakdown voltage between contacts. To achieve the improvement in breakdown voltage, fundamental research on discharge phenomena is very important. We studied the relationship between applied voltage to cause discharge and movement of carriers for rhodium-plated contact reed switches. Using Auger electron spectroscopy (AES), we analyzed contact surfaces before and after discharge caused by various applied voltages. Amount of nitrogen and amount of oxygen were found to increase on the cathode surface and on the anode surface, respectively, after discharge. Furthermore, we found that this increase was accelerated by enhancing applied voltage to cause discharge. On the contrary, amount of oxygen was found to decrease on the cathode surface after discharge. We found that this decrease was also accelerated by enhancing applied voltage to cause discharge. These results revealed that the nitrogen cation and oxygen anion moved as carriers through discharge and that this movement was accelerated by increasing applied voltage to cause discharge.
{"title":"Relationship between applied voltage to cause discharge and movement of carriers for rhodium-plated contact reed switches","authors":"K. Hinohara, K. Nakamura, T. Kobayashi, T. Miyata","doi":"10.1109/HOLM.1993.489691","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489691","url":null,"abstract":"Reed switches have been used in various fields of application due to excellent reliability and compactness. The progress of electronics is leading to increasing demand for enhanced functions of the reed switch. One such demand is high breakdown voltage between contacts. To achieve the improvement in breakdown voltage, fundamental research on discharge phenomena is very important. We studied the relationship between applied voltage to cause discharge and movement of carriers for rhodium-plated contact reed switches. Using Auger electron spectroscopy (AES), we analyzed contact surfaces before and after discharge caused by various applied voltages. Amount of nitrogen and amount of oxygen were found to increase on the cathode surface and on the anode surface, respectively, after discharge. Furthermore, we found that this increase was accelerated by enhancing applied voltage to cause discharge. On the contrary, amount of oxygen was found to decrease on the cathode surface after discharge. We found that this decrease was also accelerated by enhancing applied voltage to cause discharge. These results revealed that the nitrogen cation and oxygen anion moved as carriers through discharge and that this movement was accelerated by increasing applied voltage to cause discharge.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73273232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489664
J. McBride, S. Sharkh
This paper presents experimental results on the influence of contact opening velocity and the moment of contact opening with respect to the start of the AC current cycle on arc energy and contact erosion when breaking an AC resistive circuit. The test currents are 5.6 A, 14.7 A and 26.3 A, and the contact material is Ag/CdO (90/10). A computer controlled test system allows the control of the contact velocity profiles with constant velocities up to 0.8 m/s, and also enables the synchronization of the contact opening with a point on the AC current waveform. Contact erosion is evaluated by measuring the mass loss or gain changes of the cathode and anode. The results show that increasing the contact velocity from 0.1 m/s to 0.8 m/s leads to the increase of the arc energy. The material transfer from one electrode to another is shown to depend on the current, the polarity of the moving contact, the moment of the contact opening with respect to the start of the AC current cycle, and the opening velocity of the contacts.
{"title":"The effect of contact opening velocity and the moment of contact opening on the AC erosion of Ag/CdO contacts","authors":"J. McBride, S. Sharkh","doi":"10.1109/HOLM.1993.489664","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489664","url":null,"abstract":"This paper presents experimental results on the influence of contact opening velocity and the moment of contact opening with respect to the start of the AC current cycle on arc energy and contact erosion when breaking an AC resistive circuit. The test currents are 5.6 A, 14.7 A and 26.3 A, and the contact material is Ag/CdO (90/10). A computer controlled test system allows the control of the contact velocity profiles with constant velocities up to 0.8 m/s, and also enables the synchronization of the contact opening with a point on the AC current waveform. Contact erosion is evaluated by measuring the mass loss or gain changes of the cathode and anode. The results show that increasing the contact velocity from 0.1 m/s to 0.8 m/s leads to the increase of the arc energy. The material transfer from one electrode to another is shown to depend on the current, the polarity of the moving contact, the moment of the contact opening with respect to the start of the AC current cycle, and the opening velocity of the contacts.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85301737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489689
T. Yamamoto, K. Sawa
Palladium oxide formed on the electrode surfaces of palladium electrical contacts by a mechanochemical reaction during mechanical switching generally causes significant contact resistance rise. In the present paper, the influence of oxygen concentration and humidity on this phenomenon is examined. It has been found that palladium oxide is formed even when the oxygen concentration is less than 0.01% under the condition that influence of aqueous vapor or organic gases is negligible. As the oxygen concentration decreases, both the contact resistance and the palladium oxide formation rate decrease. Experimental results indicate that the presence of water delays or prevents palladium oxide formation. The proposed model for this effect is that water molecules absorbed onto the contact surfaces act to lubricate to smooth the contact spots, thereby minimizing the palladium oxide formation rate.
{"title":"Influence of oxygen concentration and humidity on palladium oxide formation by a mechanochemical reaction","authors":"T. Yamamoto, K. Sawa","doi":"10.1109/HOLM.1993.489689","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489689","url":null,"abstract":"Palladium oxide formed on the electrode surfaces of palladium electrical contacts by a mechanochemical reaction during mechanical switching generally causes significant contact resistance rise. In the present paper, the influence of oxygen concentration and humidity on this phenomenon is examined. It has been found that palladium oxide is formed even when the oxygen concentration is less than 0.01% under the condition that influence of aqueous vapor or organic gases is negligible. As the oxygen concentration decreases, both the contact resistance and the palladium oxide formation rate decrease. Experimental results indicate that the presence of water delays or prevents palladium oxide formation. The proposed model for this effect is that water molecules absorbed onto the contact surfaces act to lubricate to smooth the contact spots, thereby minimizing the palladium oxide formation rate.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83745560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489675
M. D. Bryant
A comprehensive model to predict the contact resistance during the nth fretting cycle and the ultimate usable lifetime of the contact has been developed. This model incorporates contact wipe, fretting vibration amplitude and frequency, contaminant chemistry, material properties, plating thickness, asperity deformations, normal load, electrical load, and surface topography. It is assumed that fretting vibrations separate contacting asperities and expose virgin metallic a-spots to environmental contaminant attack. The model calculates the amount of corrosive product produced on the exposed surfaces during the separation phase of a cycle of fretting. As fretting motions pull the exposed corroded asperities back together, a mismatch in size occurs and some of the corrosive product is scraped off and deposited in the valleys. Eventually, the valleys fill and separate the a-spots, resulting in "ultimate" failure. A material balance between amounts produced and scraped off estimates the amount of corrosive product dragged into the contact. Shifting of molecules via plastic deformation mix particles of corrosive product into the asperity metal. Assumptions that correlate mixing to plastic flow and use of modern composite theory leads to an estimate of the conductivity within the contaminated asperity. Integration over the asperity volume gives the asperity resistance, and application of Greenwood's theory estimates the total contact resistance. Results show a monotonic increase in contact resistance over time. Initial increases are slow, followed by rapid increases. Predicted failure times are consistent with field measurements.
{"title":"Resistance buildup in electrical connectors due to fretting corrosion of rough surfaces","authors":"M. D. Bryant","doi":"10.1109/HOLM.1993.489675","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489675","url":null,"abstract":"A comprehensive model to predict the contact resistance during the nth fretting cycle and the ultimate usable lifetime of the contact has been developed. This model incorporates contact wipe, fretting vibration amplitude and frequency, contaminant chemistry, material properties, plating thickness, asperity deformations, normal load, electrical load, and surface topography. It is assumed that fretting vibrations separate contacting asperities and expose virgin metallic a-spots to environmental contaminant attack. The model calculates the amount of corrosive product produced on the exposed surfaces during the separation phase of a cycle of fretting. As fretting motions pull the exposed corroded asperities back together, a mismatch in size occurs and some of the corrosive product is scraped off and deposited in the valleys. Eventually, the valleys fill and separate the a-spots, resulting in \"ultimate\" failure. A material balance between amounts produced and scraped off estimates the amount of corrosive product dragged into the contact. Shifting of molecules via plastic deformation mix particles of corrosive product into the asperity metal. Assumptions that correlate mixing to plastic flow and use of modern composite theory leads to an estimate of the conductivity within the contaminated asperity. Integration over the asperity volume gives the asperity resistance, and application of Greenwood's theory estimates the total contact resistance. Results show a monotonic increase in contact resistance over time. Initial increases are slow, followed by rapid increases. Predicted failure times are consistent with field measurements.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82207877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489659
M. Myers
The tensile properties and cold heading response of two Ag/CdO and three Ag/SnO/sub 2/ electrical contact alloys have been determined and compared. Tensile data and data from a simple compression test could not be used to predict headability. The Ag/SnO/sub 2/ compositions were found to be significantly less headable than the Ag/CdO compositions.
{"title":"Mechanical properties and heading characteristics of some Ag/CdO and Ag/SnO/sub 2/ compositions","authors":"M. Myers","doi":"10.1109/HOLM.1993.489659","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489659","url":null,"abstract":"The tensile properties and cold heading response of two Ag/CdO and three Ag/SnO/sub 2/ electrical contact alloys have been determined and compared. Tensile data and data from a simple compression test could not be used to predict headability. The Ag/SnO/sub 2/ compositions were found to be significantly less headable than the Ag/CdO compositions.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82044033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489656
Ming Sun, Qiping Wang, M. Lindmayer
Based on switching experiments with cylindrical contacts of different diameters by high speed camera observations and SEM micrographs, the effects of phase change, viscosity and surface tension on erosion losses of AgMeO contact materials are analysed during arcing in the current range up to 1000 A rms. The erosion model of AgMeO is used for expressing the heat-force function during arc-electrode interaction and the liquid-solid, liquid-gas boundary corresponding to the upper and lower erosion limit respectively for the reason that erosion is composed of two modes: evaporation and minute molten droplets losses. Furthermore, supposing that the arc column is a hypothetical "point heat source" in middle of the gap, a new erosion mathematical model is established by the finite differential method and the results coincide well with those of experiments.
通过高速相机观察和SEM显微照片，对不同直径的圆柱触点进行了切换实验，分析了在1000 A rms电流范围内电弧过程中，相变、粘度和表面张力对AgMeO触点材料侵蚀损失的影响。由于侵蚀由蒸发和微小熔滴损失两种模式组成，因此采用AgMeO的侵蚀模型来表示电弧-电极相互作用过程中的热力函数以及对应于侵蚀上限和下限的液-固、液-气边界。在此基础上，假设弧柱为间隙中间的一个假设“点热源”，采用有限微分法建立了新的侵蚀数学模型，并与实验结果吻合较好。
{"title":"The model of interaction between arc and AgMeO contact materials","authors":"Ming Sun, Qiping Wang, M. Lindmayer","doi":"10.1109/HOLM.1993.489656","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489656","url":null,"abstract":"Based on switching experiments with cylindrical contacts of different diameters by high speed camera observations and SEM micrographs, the effects of phase change, viscosity and surface tension on erosion losses of AgMeO contact materials are analysed during arcing in the current range up to 1000 A rms. The erosion model of AgMeO is used for expressing the heat-force function during arc-electrode interaction and the liquid-solid, liquid-gas boundary corresponding to the upper and lower erosion limit respectively for the reason that erosion is composed of two modes: evaporation and minute molten droplets losses. Furthermore, supposing that the arc column is a hypothetical \"point heat source\" in middle of the gap, a new erosion mathematical model is established by the finite differential method and the results coincide well with those of experiments.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83037559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489679
S. Benhenda, N. Benjemâa, M. Bourir
Pulse plated nickel coatings on copper and copper alloys were investigated in view of their use as underlayer in Au/Ni/Cu or as external protective coatings. Deposition parameters were varied in order to determine their influence on the microstructure and consequently on the electrical contact properties of the electrodeposited Ni films. Roughness and hardness measurements as well as SEM studies were performed on these samples. Smooth and dense coatings were obtained for high pause-to-pulse ratio, 25-75 Hz pulse-plating frequencies and low current density. The contact resistances R/sub c/ of the as-deposited samples in approach and insert mode were measured versus load F/sub c/ in the range 0.1-10 N. It was found that initial contact resistance follows the power law R/sub c/=KF/sub c//sup -n/ where n is hardness and coating topography dependent. Moreover, aging samples in daily cyclic atmosphere shows an increase in contact resistance during the test, but ohmic behaviour prevails as verified by the current-voltage characteristics. Finally, the mechanical behaviour investigated by a fretting study shows that the pulse reverse condition improves contact resistance stability.
{"title":"Effect of pulse plating parameters on electrical contact behaviour of nickel coatings","authors":"S. Benhenda, N. Benjemâa, M. Bourir","doi":"10.1109/HOLM.1993.489679","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489679","url":null,"abstract":"Pulse plated nickel coatings on copper and copper alloys were investigated in view of their use as underlayer in Au/Ni/Cu or as external protective coatings. Deposition parameters were varied in order to determine their influence on the microstructure and consequently on the electrical contact properties of the electrodeposited Ni films. Roughness and hardness measurements as well as SEM studies were performed on these samples. Smooth and dense coatings were obtained for high pause-to-pulse ratio, 25-75 Hz pulse-plating frequencies and low current density. The contact resistances R/sub c/ of the as-deposited samples in approach and insert mode were measured versus load F/sub c/ in the range 0.1-10 N. It was found that initial contact resistance follows the power law R/sub c/=KF/sub c//sup -n/ where n is hardness and coating topography dependent. Moreover, aging samples in daily cyclic atmosphere shows an increase in contact resistance during the test, but ohmic behaviour prevails as verified by the current-voltage characteristics. Finally, the mechanical behaviour investigated by a fretting study shows that the pulse reverse condition improves contact resistance stability.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76414894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489653
M. Lindmayer
Nowadays in circuit breakers from the low voltage level to the highest transmission voltages, contacts to carry the current and arcs established at contact opening to break it are utilized. Of the various possible but scarcely used alternatives to this principle, the transition between the superconducting and normal-conducting state has gained new attention since the high T/sub c/ superconductors (HTSCs) have been discovered. This paper assesses the technical possibilities and problems of resistive current limiters with such superconductors. Based on results of experimental investigations of HTSC samples, simulations of the behavior of fictive HTSC limiters in electrical power networks are carried out. Assuming a homogeneous conductor, the self-quench initialized by exceeding the critical current is calculated for conductors with different critical current densities. Furthermore, questions of inhomogeneity along the conductor, current pulse triggering, transient overvoltages and the effect of parallel elements are discussed.
{"title":"High temperature superconductors as current limiters-an alternative to contacts and arcs in circuit breakers?","authors":"M. Lindmayer","doi":"10.1109/HOLM.1993.489653","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489653","url":null,"abstract":"Nowadays in circuit breakers from the low voltage level to the highest transmission voltages, contacts to carry the current and arcs established at contact opening to break it are utilized. Of the various possible but scarcely used alternatives to this principle, the transition between the superconducting and normal-conducting state has gained new attention since the high T/sub c/ superconductors (HTSCs) have been discovered. This paper assesses the technical possibilities and problems of resistive current limiters with such superconductors. Based on results of experimental investigations of HTSC samples, simulations of the behavior of fictive HTSC limiters in electrical power networks are carried out. Assuming a homogeneous conductor, the self-quench initialized by exceeding the critical current is calculated for conductors with different critical current densities. Furthermore, questions of inhomogeneity along the conductor, current pulse triggering, transient overvoltages and the effect of parallel elements are discussed.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75321213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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