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The fuse-link is short-circuited during the test and the current passing through both the fuselink* P8 V x" M# a: M* h5 E
and the short-circuit link under the relevant fault condition, is measured:
* r& e" a- }# y: X$ q– if this current remains less than 2,1 times the rated current of the fuse-link, the
4 l/ q& D7 m$ \# btemperatures are measured after a steady state has been attained;; h" s9 J- y* [. s( j# M+ c/ u
– if this current is either immediately 2,1 times the rated current of the fuse-link or more, or' R! K7 H* E3 c
reaches this value after a period of time equal to the maximum pre-arcing time for the
( q* S! u' I6 j1 ~: Q+ ?3 z+ M7 \+ M* Qrelevant current through the fuse-link under consideration, both the fuse-link and the shortcircuit, X7 E, b- T. A- b8 V
link are removed after an additional time corresponding to the maximum pre-arcing
% d0 N: u. I9 qtime of the fuse-link under consideration and the temperatures are measured immediately.
' _* y }4 S$ i! K9 W/ H1 _& d1 t. m2 o& o# ^
以上是有关熔断体的操作问题,我想问的是:: L) z3 j' [2 H
1.为什么是2.1倍的额定电流值,不是1.5倍,2倍,也就是为什么是2.1不是其他值
* @& v: B- ?8 H$ l2.pre-arcing time 怎样计算呢? |
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