|
引用第1楼yanfenghmm于2010-01-06 09:17发表的 :8 U- e" |2 w( ~& b7 A4 D! U0 s, W
标准应该有具体要求吧。 文字的要求有时是含混不清的,要看读者的理解呀3 {2 x/ R" L$ s; q$ R- `9 Y# D
下面是table 4:5 K) h6 |- i a/ i6 L( {4 J/ M* o
.! X9 r. `; f( [% p
, }) l) P2 H q. ^* Q6.7.1.1 CLEARANCES
+ O3 l. f5 @( l5 |CLEARANCES are specified to withstand the maximum transient overvoltage that can be
% F+ p$ K3 p" C+ [present on the circuit, either as a result of an external event (such as a lightning strike, or a/ I5 g, Z& M7 t- U5 b: e
switching transient), or as the result of the operation of the equipment. If transient
2 w9 u7 o, a0 @0 r, Oovervoltages cannot occur, CLEARANCES are based on the maximum WORKING VOLTAGE.
' ^2 ?0 a; O5 DThe value for CLEARANCE depends on! Z/ C/ M, H, F
a) the type of insulation (basic insulation, reinforced insulation, etc.);
& E* K% b9 m. u" b Eb) the POLLUTION degree of the micro-environment of the CLEARANCE. o! }) C& y3 Z9 C2 g' B T* u
: q% @+ ~8 R ]
6.7.1.2 CREEPAGE DISTANCES9 k* w3 y$ H* M" p# f: i
For CREEPAGE DISTANCES between two circuits, the actual WORKING VOLTAGE which stresses
0 H8 G9 J5 |! }the insulation between the circuits shall be used. Linear interpolation of CREEPAGE DISTANCE is
9 a& ^5 ]4 J7 m4 Opermissible. CREEPAGE DISTANCE shall always be at least as large as the value specified for
. _( I( O# M F1 a ]4 f7 r" ICLEARANCE.
" F3 f+ t. D+ c5 V; v
( r. s5 R0 x0 b一般而言电气间隙被设计为耐受最高瞬时过电压,经常会考虑工作电压峰值带来的影响;而爬电距离被认为是耐受工作电压有效值的。7 o* l" A. }1 R% B! h8 b
从上面两大块文字中,该标准中6.7.1.1看不出电气间隙要考虑工作电压(peak or rms)的要求,但6.7.1.2爬电距离明确说明要考虑工作电压。而table 4中第一列表头只写了"Voltage line-toneutral
) T O* u" d/ m. I9 v- a" |a.c. r.m.s. or d.c.",也没有提"working voltage"。所以实际查表时我就犯难了,到底如何操作呢,请高手指教! |
本帖子中包含更多资源
您需要 登录 才可以下载或查看,没有帐号?注册安规
x
|