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以下UL PAG中的对保险管炸开的现象的判定指导:
- D% g( e: W* I. n, Z! j2 D- c5.3.8-1 Bursting fuses' } q8 s5 ~3 I
STANDARD IEC/UL 60950-1/ @7 t" C3 K E7 w8 x% S+ v3 i3 z
APPLICABILITY UL(C-UL) and IEC. U' g1 H9 l/ B0 A6 I9 v* A! ?9 Y8 J
(Sub)CLAUSE/ANNEX NUMBER: 5.3.8' e1 K. m0 X: i4 j0 \ o- Y- ]
(Sub)CLAUSE/ANNEX HEADING: Compliance Criteria for Abnormal Operating and Fault Conditions* ~4 S+ G# V0 P# @0 _
OTHER RELEVANT (Sub)CLAUSES/ANNEXES }% V+ y3 J; P8 m$ z( n
(as Applicable):! T. {. O0 \7 j+ ]
2.7.3, 5.3.6, 5.3.8.1, 5.3.8.25 w% [3 I4 w* T
DESCRIPTION OF ISSUE:! V, Q. b9 D+ {, |" {
Type of Issue: Technical6 X8 E! Y+ V) _6 L/ C/ |
During fault testing in the Primary circuits of switch mode power supplies (SMPS) and other ITE,
) s; L4 \2 B# Z. @# ~. f" w. U& j! msometimes a fuse that provides supplementary (non-branch circuit) overcurrent protection and) Q8 W8 g& I( n& ~! S8 M
that complies with either IEC 60127 or UL 248-14 will burst while clearing the circuit: L: J! H/ U! N
Is this an acceptable result and termination of the test?
) S& _: q; G$ ]& ^5 }5 wAPPLICATION GUIDELINE:8 ~! ?4 l8 x! P) f0 Q
A fuse that bursts is not an acceptable result and termination of a test. If a fuse bursts during
# P# R7 | t! f6 C- Hfault testing per sub-clause 5.3, it does not have adequate breaking (rupturing) capacity.
( D: i% a# U: M" p6 h" FTherefore, such a fuse should be replaced by the manufacturer with another fuse having high
1 b" a% q4 L' M/ J- S2 bbreaking capacity. This consideration applies to fuses complying with both IEC 60127 and UL
7 V7 m: c7 u8 N! o6 {248-14.
% p# e. m% S/ u+ @! FPlacement of heat shrink or similar tubing over the fuse assembly is not a suitable solution to2 u5 p' \# I4 M( Q4 u) A) p
wholly mitigate potential hazards associated with a bursting fuse. |
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