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发表于 2009-5-8 15:06
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引用第10楼franco于2009-05-07 20:39发表的 :
. C2 H6 z9 N2 j8 R% \The oscillating member is moved backwards and forwards through an angle of 90° (45° on 3 p# l9 u4 d6 }; q
either side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per 7 v( i% F! F- R/ | k
min. A flexing is one movement, either backwards or forwards. After 10 000 flexings, the & u. ~+ d s) a! B, S. \
sample is turned through 90° about the centre line of the cord guard.
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.......
5 Y- T h5 o+ }" X2 _% T翻译成中文的主要意思就是：
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The oscillating member is moved backwards and forwards through an angle of 90° (45° on
+ T1 m1 s- B- K8 }+ d/ Y; l8 `6 L! x. l' ^either side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per 2 V9 F, E1 @, m6 a& `0 B
min. - 摇摆装置能够在90°的范围内前后摆动（其中这个90°指的是沿垂直位置两边各45°），以每分钟60次的频率摇摆20000次。
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这句话讨论的是仪器的摆动机构要满足的特性，就是要能在90°的范围内前后摆动，如果只能在45°的范围内摆动的话，这个设备就是不符合要求的。这句话并没有涉及到一个摆动周期如何定义啊。8 ]' x3 _9 [" u. x5 S$ R+ B
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After 10 000 flexings, the sample is turned through 90° about the centre line of the cord guard. - 10000次摆动之后，将样品沿着电线防护套的中心线转动90°。" M+ J9 S. }2 c2 U) W; }
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这句话说的是总共20000次的摆动样品应该在两个位置分两次完成而已，同样没有涉及到摆动周期的解释和说明。
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b1 l; k2 q4 i& G7 }: C& i3 ~) v( K最重要的一句话应该是：A flexing is one movement, either backwards or forwards. - 一次摇摆就是一次移动，无论是向后还是向前的。1 D) X' p9 t) G& M: w
: I5 j0 o4 }* I4 ~ y& {1 ?这句话虽然容易引起歧义，但是仔细考虑一下也不是很难理解。可以看出，1个摆动周期就是单次的向前或者向后的移动。摇摆机构是在总共90°范围内摆动，那不管是向前还是向后的摆动角度都是45°了。由此可以得出1个摇摆周期就是45°而不是我们通常认为的90°。
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摘抄UL 745-1标准中的相关章节如下，关于这个问题解释的非常清楚，供大家参考参考：2 J& h2 ?4 W" ~% u! p: ^" T
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A flexing is one movement, either backwards or forwards. That is, from vertical to 45° in one direction is the first flex, from there back to vertical is the second flex, from vertical to the opposite 45° is the third flex, from there back to vertical is the fourth flex, continuing until 10000 flexes have occurred. |
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发表于 2009-5-7 20:39
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