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請教一下什麼是螺釘有接觸壓力跟沒有接觸壓力??5 S7 @- h* \* c' l+ x7 d4 Z- m
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, K4 C6 o" S7 v) f0 ^& q; k17 Electrical connections and mechanical fixings9 x; }& u/ y* u/ ?
17.1 DE Screw TERMINALS providing electrical contact and screw fixings which during the life of the
3 a; Q, ]3 q8 japparatus will be loosened and tightened several times shall have adequate strength.
4 \5 j: G2 }- L$ b; iScrews exerting contact pressure and screws with a nominal diameter less than 3 mm which form part of
: O& @7 ~ s, M0 L/ B% `the above-mentioned screw fixings shall screw into a metal nut or a metal insert.
4 U& v& w* z3 W- p2 P! C* IHowever, screws having a nominal diameter less than 3 mm, which do not exert contact pressure, need
2 ]8 g1 v: g$ U+ i$ fnot be screwed into metal, provided that the screw fixing withstands the torque specified in table 20 for4 w+ W5 W. f7 w! d" j
screws of 3 mm diameter. |
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