非常感谢您。我有疑问的是:测试输出端子断地测试,是从输入端把断开(线路中的E开关);
还是从次级把输出负与地线断开呢(就是把地线接次级点断开)。有什么判定依据吗?从标准里哪能找得到呢?
因为以上两种断地测试的结果是不一样的,假如初级有与地的桥接Y电容的话。
For equipment having a protective earthing connection or a FUNCTIONAL EARTHING connection,
terminal A of the measuring instrument is connected via measurement switch "s" to the main
protective earthing terminal of the EUT, with the earthing conductor switch "e" open.
The test is also conducted, on all equipment, with terminal A of the measuring network
connected via measurement switch "s" to each unearthed or non-conductive accessible part
and each unearthed accessible circuit, in turn, with the earthing conductor switch "e" closed
这是标准上面说的,意思就是有地断地,没地接地~~
如果你输入地断开来测得话,那得按3.5来卡(这和测接地金属外壳是一样的结果),但是标准里面讲我们测得地方是switch "s" to the main
protective earthing terminal of the EUT,输出端子负端接地如果不能过接地连续性测试的话,他只能算是功能地,按没有接地的方式来测,输入的地接上,输出的地如果不断开测得值是个定值上面我有说过,所以输出端子负端地断开,那就按0.25来卡,一般是按这种方法来测得。 好问题,但不是难题。
标准说有接地的(可靠性接地或是功能性接地),需要把EUT的接地端子断开,限定值为3.5mA, 在测试时也没有问题,看认证单位工程师的想法了,不过都可以测过的。
例如,当二次电路有功能性接地时,判定值也是3.5mA, 这时,EUT的接地与电源地要断开;若以0.25mA来判定时,则需要把EUT的地与电源地接通。
若是测量可靠性接地的部位时,则是3.5mA限定值, 这时,EUT的接地与电源地要断开。
这个是我们在操作进的做法,基本上所有的认证单位都不会有问题,如UL, TUV RH, TUV PS, NEMKO, ITS 引用第10楼琥珀流云于2011-12-06 17:22发表的:
For equipment having a protective earthing connection or a FUNCTIONAL EARTHING connection,
terminal A of the measuring instrument is connected via measurement switch "s" to the main
protective earthing terminal of the EUT, with the earthing conductor switch "e" open.
The test is also conducted, on all equipment, with terminal A of the measuring network
.......
谢谢大哥,我清楚了,说白了,只要跨接在初次级之间的Y电容不要大于2200PF基本上都没问题了。。
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