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先上标准,IEC 60065 Annex N(routine test):
" P+ f( S/ z- d" t" ON.1.3 Protective earthing connection of screens and metal barriers) P$ [2 e, U* _
For CLASS I apparatus with a screen or metal barrier (see 8.5) between HAZARDOUS LIVE parts, z d' } u/ }, B; D
and TERMINALS regarded as ACCESSIBLE (see 8.4) or ACCESSIBLE conductive parts respectively,4 J1 ]3 P6 w, ~1 E
the continuity of the protective earthing connection should be checked as late as possible$ N2 V( G. ~) K2 y. x1 S
during the production process between the screen or metal barrier and+ b9 I* F3 I' ^
– the protective earthing contact of the MAINS plug or appliance inlet, or, ]' e0 s. L, X8 U
– the PROTECTIVE EARTHING TERMINAL in case of a PERMANENTLY CONNECTED APPARATUS.) c) t9 r9 Q% J3 ]: H
The test current applied for 1 s to 4 s should be in the order of 10 A a.c., derived from a source
: A6 ?1 @* t. Xhaving a no-load voltage not exceeding 12 V." Q' P4 b/ f9 k( f9 t: I
The measured resistance should not exceed
9 }; k, ?+ Z' D/ G) F– 0,1 Ω for apparatus with a detachable power supply cord,2 h3 ?; j c) S9 U' l' H
– 0,2 Ω for apparatus with a non-detachable power supply cord.
6 _9 J' \% j) [9 cNOTE Care should be taken that the contact resistance between the tip of the measuring probe and the metal4 N- Z/ G4 b9 }8 M
parts under test does not influence the test results.# O% H, n& T, X% b
$ |9 P; `1 ]1 e4 r* a2 z6 @红字部分是我的疑惑,为什么会有0.2的要求呢?这个出于什么考虑,是所有情况都是这样吗?还是需要有 screen or metal barrier 的情况下才有。正常情况下应该是按照15.2中关于接地导通的要求:
! A% b& J% {7 c2 yThe resistance of the connection between the PROTECTIVE EARTHING TERMINAL or contact, and
C& L8 _3 a* ?% g1 yparts required to be connected thereto, shall not exceed 0,1 Ω.
5 [+ f0 c, _) }& f我想的是为什么会有0.2的要求,请各位大神相助~~~+ H+ Y: g& @3 n" {2 J
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