DSH 659 Problem of setting a current applied to ACB of high current rating in in

小米

广东安规检测
有限公司提供：

小型摆管淋雨试验机

IPX5X6X7喷水试验机

1000L恒温恒湿箱

各种试验指现货

可程式恒温恒湿试验箱

水平垂直燃烧机

自动卷线器试验机

耐划痕试验机

各种灯头量规现货

灼热丝试验机现货

GB1002插头量规

IPX1-X7淋雨现货

IEC61347/UL935镇流器热试验箱

灯具防风罩

IK冲击试验机

UL498插头插座量规

VDE0620插头插座量规

稳定性试验台

家电温升测试角

针焰试验机现货

热电偶焊机现货

家电125mm试验指

E12灯头量规

无绳壶无绳电熨斗插拔寿命试验机

IEC60335试验指甲

DSH 659 6 I7 W$ ], |" B/ z4 @

Problem of setting a current applied to ACB of high current rating in instantaneous tripping 1 q6 o  W/ d% \$ w$ o; ^0 n. e

8.3.3.1.2 0 G( O7 T+ i# E6 h

60947-2(ed.4) ) u) z* V0 I. y

* G9 Y3 N0 l- r# z8 YStandard-
IEC 60947-2 (2006-04, 4th Ed.)
; U3 J9 V; ]% oSub clause(s):
8.3.3.1.2
1 F' Y4 B# G8 b/ e8 uSheet:
# r% u4 _: F) h+ L  WDSH 659
Subject:
Problem of setting a current applied to ACB of
$ v+ k5 N( }- i- K5 ihigh current rating for instantaneous tripping.
Key words:
6 e7 o* U  d/ @/ STrip limits &
* Y9 l- F  I7 Fcharacteristics
Approved at
the 45th CTL
1 S- W' b6 L. xPlenary
) }2 }) u* W5 _+ H' R7 M" s8 Z6 dMeeting in
Prague in 2008
) Z7 R+ H* l( H+ k5 `6 A. ?9 RQuestion:
According to 8.3.3.1.2, when the over-current opening release is a built-in part of the
- `2 u' P2 u* A, [2 w/ T) Bcircuit breaker, it shall normally be verified inside the corresponding circuit breaker.
! |$ _5 X$ n# M; }For example, in case an air circuit-breaker (ACB) has a rating of 6300 A with an
6 {9 _  d  W( F2 g7 Ainstantaneous trip release up to 16 In, do we have to apply 80640 A (16 In x 80 %)
$ y$ c8 i6 Q8 {8 Sand 120960 A (16 In x 120 %) to the main circuit of ACB by use of a high power
+ @/ n* n' w4 d+ O/ rtesting facility when performing the trip test of SEQ. I?
, e- q" n8 Z1 j) e2 }1 Z) ARationale:
0 }# i. W9 w0 M$ `3 u( U" [It is not so easy to conduct the instantaneous trip test using the high currents
mentioned above, because to do so a high power testing facility is required. In
- y% X- o& X0 _addition ACBs often have several ratings, which are determined by the specification
$ n( ^/ s( f5 p9 H; M3 Qof the CT in combination with the trip unit, and the trip unit is usually the same for all
models.
5 r# }: e& a. Z4 M& p6 PSo some accredited testing laboratories have performed this test by applying the
: c+ o* j; J# Y! x- ~$ `secondary current of CT (normally 5 A) to the input of an overcurrent release. This
7 T' G9 M- S$ v: w2 wrelease is connected to operating mechanism of contacts to check the mechanical
opening of an ACB. But by use of this method, we bypass possible problems such
as CT saturation, thermal and EMC influence on ACB, especially on single-pole
connection.
Decision:
The secondary current of the CT (reduced current, 5 A, for example) may be used
# O$ Z) q! ]+ m2 Y) z; Yfor trip tests of ACBs integrated with electronic OCR for all ratings of In, but only for
) E" I7 x, K/ M* Ysub-clause 8.3.3.1.2 of SEQ I.
But in addition, followings items shall be verified to fully cover the safety aspects of
3 M% c) G; Q5 r- R5 {the standard:
- M' I* C) }4 w0 o5 ^( u& O1. The conformity of the performance (at least turn ratio and composite error)
: N/ Y  [& Y/ @! Iof the CT or Rogowski coil, if any, shall be verified by specifications, test
reports or certificates. All CTs of the circuit-breakers of the given frame
5 o& d9 B3 E: M; Y8 j4 I$ e5 Z/ tsize have to show the same performance characteristic.
7 H% ?, ?, W1 b; P2. The single pole short-circuit test with a current equal to 80 % of the
maximum current setting of the instantaneous release and equal to 120 %
of the maximum current setting of the instantaneous release shall be
8 ?( ]8 z7 g4 Q+ fperformed at any convenient voltage with the current in the main poles of
8 w* {9 H' T" uthe circuit-breaker. The other tests required by the standard may be
conducted by use of a simulated input signal to the tripping unit.