|
请问如下这个测试怎么做啊- [/ R1 m4 {8 L) b& v. o
18 Limited Short-Circuit Test: R! a" e7 Q w( R( H
18.1 General2 r0 ?3 Z. t9 d- R
18.1.1 Following the test specified in 18.2.1 or 18.3.1, a thermistor shall:" K# r6 L. U0 i1 f2 s
a) Comply with the requirements in 11.1.2 or be in a permanently high resistance state; and2 H8 I Z9 n# D3 i, i& m: n
b) Complete the test without igniting the cotton indicator or opening the ground fuse described in
$ X m2 g# M( q& F$ L18.1.4 and 18.1.5.
9 e# {8 D- q9 \( u6 i18.1.2 When the results of the Limited Short-Circuit Test on the thermistor itself comply with 18.1.1, the
# l5 i" R0 U2 `& e" W! ]test is not required to be repeated during the investigation of the end product.
0 h5 a; k; s" U7 Q6 d18.1.3 Three samples of a control thermistor are to be subjected to this test. The test is to be conducted
% \5 w9 `/ N2 e w$ p4 V# ?at rated voltage (Vr).2 S' J4 Y' A. m" ?! U7 D
18.1.4 A ground fuse is to be connected between the metal enclosure, metal mounting surface, or metal9 L9 R. U6 @3 g: [2 l9 o
screen described in 18.1.5 and the unswitched line to indicate an arc-over to the enclosure or mounting
& u) M# L8 s/ X$ n E6 wsurface. Where each line is switched, the fuse is to be connected between the enclosure, mounting* E/ C5 Y! R( e
surface, or screen and the live pole least likely to arc to ground. The fuse is to be a 3.0 A nontime-delay2 J- g7 _+ u4 P# d+ O: f2 R: w
fuse having a voltage rating not less than the rated voltage (Vr) of the thermistor.# B# J: T. U8 `0 F) Z* D
18.1.5 Cotton not less than 12.7 mm (1/2 in) thick is to surround a metal screen enclosing the thermistor
5 L# N* l% o3 w' D) iat a distance not more than 12.7 mm from all parts of the thermistor.- h- I, \) \! T5 f( v& \9 D
18.1.6 The cotton is to be surgical cotton, such as commonly used for medical purposes. |
|