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7 L! y! X$ q' N9 E9 I8 t z* k | Varistors (VDR’s) across the mains
, x, L% |5 D' C. k | 19.11: a- B8 ]1 n1 h1 u# U$ F
| 60335-1(ed.4)
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Question:
) I y7 r, `, T8 r( oReports from different Testing Laboratories and clients expose essential differences in interpretation and testing practice between laboratories and/or Certification Bodies.7 P, @8 W# i: n1 H
Actually, the practice of one Certification Body is now being a market factor.
, z8 c% Q4 I9 R }. XBased on above concerns we ask for clarification:4 e; R+ @ w0 `/ _% `
1: Shall Cl. 19.11 be strictly followed or can solutions given under 2. be accepted.7 i! f1 K b- Q
2: Can any of the decisions (made by OSM/EE) be accepted?/ Q7 J2 c8 K3 A3 T7 M
- A: VDR’s across the mains are accepted if the VDR is separately certified according to IEC 61051-1 or according to CECC 42200.
$ V4 w* y1 E: S& m# s: G! g7 n* d- B: VDR across the mains with a protective device to guard against short-circuit is acceptable.
! \2 c4 L- B) c; c- C: If A and B are acceptable, should, because of the fact that VDR’s may burn or burst during life-time due to an increasing temperature stress caused by increase of leakage current with a number of switching cycles in the VDR, a thermal interrupting device on the VDR connected in series with the VDR be required.
p, {0 k9 k k. z y' D0 VDecision:
/ I0 C3 k4 ~1 p1. VDR’s are not short-circuited if they are used within their manufacturer’s declared specification, when tested according to Sub-clause 19.11.2 of IEC60335-1(1991).
* z/ C0 F, u) N: O) E0 f4 v8 P- f2. VDR’s are short-circuited regardless of compliance with IEC61051-1, when tested according to Subclause 19.11.2 of IEC60335-1(2001).
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发表于 2012-9-9 14:42
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