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|  PDSH 1021
2 ~+ m, y' V' F/ t. m; Z6 R$ E; o* x0 E' H) u
| Short circuit and overload protection
9 X+ P8 V0 S5 D8 x | 15.2; @, Z4 i _5 x/ z3 ?. E- [$ i
| 61558-1(ed.1);am1 & 61558-1(ed.2);am12 E# h! |- e! a7 J- m& f
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3 P i2 I, y; A6 L* yStandard(s):
/ q J; L8 W; i* n+ w: A8 q( Z( dIEC 61558-1# r. D. E$ x. A u. h# Q. n: A
All editions( g$ H( q1 }. ^9 d2 i
Subclause(s):8 e1 S/ L' m) j% |5 i; X
15.2( \' Z3 n$ A" w+ m# l+ Y
No. Year5 w2 v" a# t7 |5 h
PDSH% q$ q& k5 S; e( l# ^
1021 2010- Q7 N# W* s' @7 {2 x
Category: SAFE Developed by: ETF56 B8 G( J% ?1 v- H0 E- _$ T
OSM/LUM5 K# w1 F- R( L7 P( R
Subject:
9 V' z l: ?& y; Y# j$ }: LShort circuit and overload5 K; X$ ~2 k& Q4 ^% q- v' Y
protection
( ?/ P3 s) a. a* u# [Key words: s1 H- Q+ ?4 e6 F4 i: ?% B; Y/ V1 c- j8 b
- Transformers, ?$ k5 t" j ]3 `
- Steady state conditions
; j+ y3 y% e2 `8 a# I! F- Short circuit
/ G3 c- x' R6 W9 V0 F7 n8 LTo be approved at the 49th
! N P) Z% A3 R# U2 dCTL Plenary Meeting, in 2012
* R! K& U( J3 K2 ?' U. V$ D! DQuestion:2 L" O1 y5 x! D4 F: q
Inherently short-circuit proof transformers shall be tested by short-circuiting the output windings until N( w2 U' `- u2 U* t7 i& h! [4 H
steady-state conditions are reached.
' _2 V9 Z/ r+ ?1 L! h% U: L. kIn the IEC 61558-1 “steady-state condition” is not explained. Referring to other standards for the meaning
& T3 B! J% ] Qof “steady-state conditions”. Or “thermal stability”. The thermal stability is the change of temperature of1 i/ B4 s A: a1 y3 z; c
less than 1°C per hour. So the following questions arise:$ u) }% a2 G8 |
Is it correct to record the temperatures after one hour when temperatures didn’t change (more than 1°C/h)?
; e' Q# x: E$ I' m' RHow shall an inherently short-circuit proof transformer be assessed when the above mentioned
. J. s2 \8 r+ `requirements are fulfilled, but the transformer is damaged 6h, after reaching the steady state condition, in/ `/ f( o7 u5 a9 t/ ? M
a way where safety will be impaired (the transformer bursts).
0 E7 _: W4 C( N: a& S4 z3 TDecision:
- |1 z% J: i2 w; _: wYes. The transformer should not be accepted because the insulated materials are not corresponding to the
) E2 |. K; m% }: x1 w8 |" K* Ainsulation class of the transformer.
$ \- j$ s2 B$ i' g! @
1 n! n% G( T5 b9 C6 G6 E8 m; p" h$ L% R% ]% c# s
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发表于 2012-11-8 15:17
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