DSH 709/06 Short circuit and overload protection

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 709/06 ! V( x- r, M: |2 e

Short circuit and overload protection ) I( B; U; B0 J! x: T1 I

15.2

61558-1(ed.2)   m6 e, x+ o- q( q  D0 ^9 s5 @

5 ^9 c2 U% A' d: }- b3 ]Standard(s): IEC 61558-1/2005 No. Year
DSH
0709
2008
6 O: y# @, }5 P: gCategory: SAFE
1 K. |* `  Y! v% |* Z' w* ?, ySubclause(s): 15.2
Developed by: ETF5
OSM/LUM
+ G$ u: c5 M! y! Z! c8 WSubject: Short circuit and
overload protection
Key words:
# Z7 G: J  D- i* t/ a- Transformers
- Steady state conditions
- Short circuit
& C0 r- m4 Y8 _, Y" CDecision approved at the
46th CTL Plenary Meeting,
/ p9 u9 s) |3 m8 S: n+ fin 2009
Question:
Inherently short-circuit proof transformers shall be tested by short-circuiting the output windings until
steady-state conditions are reached.
" n: }2 @+ Q+ A& F+ V/ t5 E/ u+ aIn IEC 61558-1 “steady-state condition” is not explained. Referring to other standards the meaning of
$ V4 P8 g( E% O“steady-state conditions” or “thermal stability” is that the change of temperature is less than 1°C per hour.
' |8 h& t4 l/ ^& i0 j; F" _So following questions arise:
  V1 y6 G2 H- W: g' L3 m) f1) Is it correct to record the temperatures after one hour when temperatures did not change (more
) ]3 x$ _) P- f6 u+ Uthan 1°C/h)?
0 F! d7 g/ V4 m  t2) How shall an inherently short-circuit proof transformer be assessed when the above mentioned
requirements are fulfilled, but it is damaged 6h after reaching the steady state condition in a way
0 O2 c0 y3 O1 a% S# Zwhere safety will be impaired (the transformer bursts).
* A' n' F4 K& F* ^2 `/ I; BDecision:
1) Yes.
2) The transformer should not be accepted.
) I. D9 U$ a! A. ]" T# Q+ |
7 ?7 |% E# |- L$ S: }" b