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引用第10楼franco于2009-05-07 20:39发表的 :
1 X: F$ D: T+ B+ L1 ?The oscillating member is moved backwards and forwards through an angle of 90° (45° on
v1 O( U- d2 D( r2 ~4 C. r L A6 ?either side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per # B/ b, p' N0 I1 W
min. A flexing is one movement, either backwards or forwards. After 10 000 flexings, the / W- o% ?1 y3 q. O) D* k' a
sample is turned through 90° about the centre line of the cord guard.
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....... 是的,这段话写的确实很明白,但是我估计你还是理解错了。* r2 h) `- Y) G
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翻译成中文的主要意思就是:
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Q" o8 I+ L$ H& W rThe oscillating member is moved backwards and forwards through an angle of 90° (45° on
( d, V5 @) c. _7 N& Yeither side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per
* i4 ?8 O) w1 v, U/ |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。
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/ q% j K2 }8 ~, m+ z$ yAfter 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°。% D% B# P8 C6 C& j1 _1 q& s
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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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; Q V0 i y( d+ y+ s, g% x, Z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。2 x$ @$ E, [7 |( X8 M
6 S* x% x; J$ ]" l9 f5 N0 D5 n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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8 K$ n% y7 Y; W2 N; w* U7 w( b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:
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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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