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以下UL PAG中的对保险管炸开的现象的判定指导:( b. a( d! t1 J9 {/ _ R; H# F
5.3.8-1 Bursting fuses S' `! @- N- l1 H
STANDARD IEC/UL 60950-1+ [0 R6 q% m; z' y
APPLICABILITY UL(C-UL) and IEC
7 [, r: B& r h& k" Y+ R1 ?(Sub)CLAUSE/ANNEX NUMBER: 5.3.8. c* Z( V+ \/ K- w2 ]
(Sub)CLAUSE/ANNEX HEADING: Compliance Criteria for Abnormal Operating and Fault Conditions7 u2 f$ y5 [2 y& z' P$ K
OTHER RELEVANT (Sub)CLAUSES/ANNEXES3 I# | g+ i( e6 w( j; q( n
(as Applicable):
0 b. N0 M5 t: S3 ]3 {! s& H) s2.7.3, 5.3.6, 5.3.8.1, 5.3.8.2
' j/ p A# Y0 {0 f0 Y, KDESCRIPTION OF ISSUE:
) z" {! U" d5 l) h, ~* T; lType of Issue: Technical0 Y, x' L2 x1 ?* O
During fault testing in the Primary circuits of switch mode power supplies (SMPS) and other ITE,
# R( w1 M3 q8 ^, R i& }sometimes a fuse that provides supplementary (non-branch circuit) overcurrent protection and; m# ]5 T$ C- {- |6 f; X. n g
that complies with either IEC 60127 or UL 248-14 will burst while clearing the circuit+ B1 p. E5 i8 T: |2 o3 R
Is this an acceptable result and termination of the test?& f( a, F. R5 }# ^) v$ T- ^
APPLICATION GUIDELINE:" E# b4 Q) o8 ?
A fuse that bursts is not an acceptable result and termination of a test. If a fuse bursts during' O& y/ S7 @5 P
fault testing per sub-clause 5.3, it does not have adequate breaking (rupturing) capacity.
9 s0 e+ B, K$ S: l; QTherefore, such a fuse should be replaced by the manufacturer with another fuse having high
$ V0 X1 x0 g( Nbreaking capacity. This consideration applies to fuses complying with both IEC 60127 and UL
) J# w" h0 |& {9 j248-14.4 d- @3 ~$ H) T. S+ M7 l+ [
Placement of heat shrink or similar tubing over the fuse assembly is not a suitable solution to$ T7 Q8 e7 a9 D# \0 }4 |4 e
wholly mitigate potential hazards associated with a bursting fuse. |
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