Study on Generation Mechanism of Radio-Wave Noise in High Speed Sliding-Contacts and Reduction Method

为了保护铁路沿线的电磁环境，降低受电弓与电车导线之间的分离现象所产生的电磁噪声水平是非常重要的。然而，由于分离现象的复杂性，目前还没有有效的降噪措施。如果这一现象可以用受电弓电流收集系统中著名的实验模型——滑动触点来解释，就有可能找到抑制射频噪声的有效方法。本研究引入了接触参数来量化滑动触点中机械接触和放电的发生情况，并试图通过对这些参数的统计测量来解释复杂的接触现象。在接触参数方面，采用黄铜滑动触点和新研制的个人计算机设备，对接触和放电的发生时间和放电速率进行了同时测量。结果表明，接触速率和放电速率近似服从正态概率分布，当滑动速度和接触负荷一定时，接触速率随接触电流的增大而减小，放电速率随接触电流的增大而增大；并且接触和放电的发生时间率的总和不依赖于接触电流，这个值出乎意料地与没有接触电流的机械接触率一致。在上述结果中，还证实了碳滑动触点的接触速率与放电速率之间的内在关系。因此，可以得出结论，脱离现象可以用上述固有性质来量化。目前，对滑动触点的分离和放电频率进行测量是为了研究滑动触点的特性。少

In preserving the electromagnetic environment along railways it is important to reduce the levels of electromagnetic noises caused by the discontact phenomenon between the pantograph and trolley wire. However no effective measures for the noise reduction have been available at the present time because of the complexities of the discontact phenomenon. If this phenomenon could be elucidated using the sliding-contacts which is well-known as an experimental model of the pantograph current-collection system, it is possible to find out drastic means for suppressing the radio-frequency noises. In this study the discontact parameters were introduced for quantifying the occurrence situations of the mechanical discontact and electrical discharge appearing in the sliding-contacts, and through statistical measurements of these parameters attempt was made to elucidate the complex discontact phenomenon. The following results were obtained : As for the discontact parameters both the occurrence time-r … More ates of the discontact and discharge were used and simultaneous measurements of the above parameters were conducted using the brass sliding-contacts and the newly developed equipment with a personal computer. As a result it was found that both the discontact and discharge rates fluctuate approximately according to the normal probability distributions and when the sliding-speed and contact load are kept constant the discontact rate decreases with increasing the contact current, while the discharge rates increase, and also that the sum of the occurrence time-rates of the discontacts and discharges does not depend upon the contact current and this value unexpectedly agrees with the mechanical discontact rate without the contact current. Among the above results the inherent relationship holding between the discontact and discharge rates was also confirmed in the carbon sliding-contacts. It was, therefore, concluded that the discontact phenomenon can be quantified by the inherent properties described above. At present measurements of the occurrence frequencies of the discontact and discharge are conducted for investigating the properties peculiar to the sliding-contacts. Less