|
|
It comes from UL 746C) {' V. O0 M- h
: j# q5 r+ s/ E. O
! D0 q4 m- M5 r0 X
1 a# k3 m3 Z. X8 c* r8 N) L55DV.4.1 In addition to the other requirements in this Standard, flammability, mechanical
$ w. p% B6 j* S5 }& ~, d5 i4 M0 yabuse and mold stress tests shall be conducted. Polymeric ENCLOSURES and covers shall" `; t3 E0 o: z3 P% M5 N
comply with the requirements for resistance to impact and drop as indicated below, and
3 g& `. K @/ Zthe requirements for mold stress release distortion, in the Standard for Polymeric Materials
5 u, D0 l4 v" b" b3 d! K- Use in Electrical Equipment Evaluations, UL 746C.# v/ r( N+ X* ~/ A. m6 d. R
! y1 A" G _; V/ u- }
In UL 746C, the standards says
5 V) d6 t' s! }1 w
- R6 D% K. w, U% z& n( w3 F+ C58.3 Each of three samples of the appliance shall be subjected to a single impact of the value shown in
) s4 q2 L7 l4 A- {0 o( M0 ]- \Table 58.1 for the applicable equipment type, on any surface that can be exposed to a blow during1 C6 S2 b# A z& j2 r+ L% I7 c$ L' ?
intended use. This impact is to be produced by dropping a steel sphere, 50.8 mm (2 inches) in diameter,$ r% G1 q5 T- o& _1 c
and weighing 0.535 kg (1 .I8 Ib) mass from the height necessary to produce the specified impact as shown0 q) H2 M# p: q4 ^% m, n
in Figure 58.2. The steel sphere shall strike the surface in a location different from those in the other two3 p" K+ g* s( B& G! L' n
impacts. For surfaces other than the top on an enclosure, either the sample could be supported on the
" V9 M2 m0 _9 W) N4 A" _side and subjected to the ball impact mentioned above, or the steel sphere is to be suspended by a cord
7 [( J' y, ^7 l/ m, w4 v5 Aand swung as a pendulum, dropping through the vertical distance necessary to cause it to strike the! z* v* `% H; I" u5 G2 L" H( O
surface with the specified impact as shown in Figure 58.2. Three samples shall be employed for the tests' j+ z2 j9 f9 Q, R. U
in the equipment restrained mode. However, if the manufacturer so elects, fewer samples may be used/ G; s5 {0 k2 C7 _; W
in accordance with Figure 58.1. The overall performance is acceptable upon completion of any one of the
% _! S. x S5 Y( f: r1 ]+ W( msequences represented in Figure 58.1. |
|
/1 
|关于安规|小黑屋|安规QQ群|Archiver|手机版|安规网
( 粤ICP13023453-10 ) 
窥视卡
雷达卡
发表于 2008-8-18 11:15
收藏
分享
好帖
鸡蛋
提升卡
置顶卡
沉默卡
喧嚣卡
变色卡
抢沙发
千斤顶
显身卡
发表于 2008-8-18 11:50
楼主
[s:87]* M" G! f1 f" |' [
