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本帖最后由 luqing_sz 于 2017-12-6 11:13 编辑
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根据IEC60335-1： 2016第27.5条规定，接地电阻测试以12V，25A施加到接地端子与器具入口处（电源线除外）之间，标准上描述施加时间为直至工作稳定状态为止，大家一般测试多长时间。。
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$ X9 e8 u1 N' `. J27.5 The connection between the earthing terminal or earthing contact and earthed metal+ l! J! a4 p+ o4 ?1 ]7 N- s
parts shall have low resistance." I! ?$ w( o- N7 m
If the clearances of basic insulation in a protective extra-low voltage circuit are based on
5 M/ a, O5 Q! @the rated voltage of the appliance, this requirement does not apply to connections providing: p3 `/ e) O3 b) ~1 i0 \
earthing continuity in the protective extra-low voltage circuit.
. R' d: ]; k: B% s* OThese requirements are not applicable to class II appliances and class III appliances that% X* K I% j9 U# |4 W
incorporate an earth for functional purposes.8 \) N. O3 G8 o& h# z
Compliance is checked by the following test.- J: o0 X8 `. Y8 w2 L8 }$ O1 c
A current derived from a source having a no-load voltage not exceeding 12 V (a.c. or d.c.) and$ F! R3 t7 }; O9 ^0 P- b
equal to 1,5 times rated current of the appliance or 25 A, whichever is higher, is passed, J+ }- h5 {' m. g5 }
between the earthing terminal or earthing contact and each of the accessible metal parts in
( I5 _, F1 U2 f, m; qturn. The test is carried out until steady conditions have been established.: K9 f5 C/ J$ E Z3 R
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+ k( m0 ~( [4 r) Z4 x6 _( e
( m/ B# y4 B4 JThe voltage drop between the earthing terminal of the appliance or the earthing contact of the
/ [$ l6 W+ ], l5 f- D* @' Sappliance inlet and the accessible metal part is measured. The resistance calculated from
- f0 ~' b4 C: v) K, G0 g7 I- dthe current and this voltage drop shall not exceed 0,1 Ω . The resistance of the supply cord is
$ T& Q( u" H' U2 Wnot included in the resistance calculation.
: j: C9 ^3 P+ v) G/ i! V y7 _NOTE Care is to be taken to ensure that the contact resistance between the tip of the measuring probe and the1 Y7 @3 A f. H3 T |
metal part under test does not influence the test results.
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