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电器的设计应有足够的爬电距离及电气间隙,同时选用的非金属材料必须具有足够的耐热、阻燃和耐漏电起痕。
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关于耐漏电起痕,有一个问题:
% b$ G& ~) P' R, \# t: i一个电气部件中用到一种PBT材料,材料的UL认证证书显示达到CTI175-250等级,而在对该材料的耐漏电起痕进行确认时发现CTI为125-150V。确认了一下试验标准,GB为4207等同IEC60112,而UL746A中的Tracking 测试方法之一为IEC Method。
+ k4 E2 x6 z9 p" ]不清楚是材料确实存在缺陷还是测试的差异造成的,请教对此问题的看法。
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UL746A的IEC Method:The test method for determining the comparative tracking index of electrical insulation materials - which is the highest voltage, as determined under the conditions specified in the Method for determining proof and comparative tracking indices of solid insulating materials, that does not cause a permanent electrically conductive carbon path within the application of 50 drops of electrolyte for 5 specimens without a persistent flame and is at least 25 volts higher than the highest voltage not to track for 100 drops for 5 specimens without a persistent flame. This test is used as a measure of the susceptibility of the material to tracking. |
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