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发表于 2012-2-24 15:34
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来自: 中国上海
本帖最后由 8756289 于 2012-2-24 15:35 编辑
回复 1# DraftMan
个人非常佩服你! 认识那么多人,现实中只有一个人是老是都问“为什么”要寻根究底,泡那么多论坛你是唯一一个为什么为什么。
来一个稍微标准点的解释:
IEC 60092-350:
4.1.1 Voltage Designation
The standard method of designation the rated voltages of cables covered by this standard shall take the form Uo/U(Um) where:
Uo is the rated power-frequency voltage between phase conductor and earth or metallic screen, for which the cable is designed;
U is the rated power-frequency voltage between phase conductor for which the cable is designed;
Um is the maximum value of the "highest system voltage" for which the equipment may be used.
All voltage are given as r.m.s. values.
这是IEC最权威的定义,其实楼上有些人回答正确了,Uo就是相电压,U就是线电压。相电压,描述的是电缆导体材料的耐压性,超过的话,自然会对导体产生不利影响,使得电缆易老化缩短使用寿命;线电压,描述的是电缆导体之间绝缘层的耐压性,超过的话,电缆导体之间的绝缘层容易被击穿,造成短路。两者描述了电缆的两个很重要的性能,所以,不是你理解的那样就是最大负载电压。
PS: 真累,IEC60092-350不给CTRL+C,一个一个字敲,还好,当复习了。 |
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