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请问如下这个测试怎么做啊- [- {4 A% B" |7 |" G/ t' B9 B
18 Limited Short-Circuit Test
/ i R h+ W" c4 k7 S8 i* Q5 `' @18.1 General
# d; l$ ]1 K6 n: E6 _18.1.1 Following the test specified in 18.2.1 or 18.3.1, a thermistor shall:: k9 p- r2 c: l2 E4 N
a) Comply with the requirements in 11.1.2 or be in a permanently high resistance state; and
$ G' S5 d/ B% w2 D2 }! |- r5 Bb) Complete the test without igniting the cotton indicator or opening the ground fuse described in- f- d$ A$ y" c" o1 P- K" E
18.1.4 and 18.1.5.4 E2 G( y4 b/ O; ?5 G! Z$ c
18.1.2 When the results of the Limited Short-Circuit Test on the thermistor itself comply with 18.1.1, the% o8 w8 |4 r0 k) Z) l, \7 j0 G
test is not required to be repeated during the investigation of the end product.
2 l) i( o+ ?( ^. x18.1.3 Three samples of a control thermistor are to be subjected to this test. The test is to be conducted
1 u g. ^) n( K) Q- g7 C: Yat rated voltage (Vr).
2 \) {1 F8 s a18.1.4 A ground fuse is to be connected between the metal enclosure, metal mounting surface, or metal. t" ~' g; n" P# g7 u5 I* U) Z
screen described in 18.1.5 and the unswitched line to indicate an arc-over to the enclosure or mounting
8 t7 a: I+ G! Y+ r# `0 b9 o; `surface. Where each line is switched, the fuse is to be connected between the enclosure, mounting0 S* k7 g* z8 I3 p3 f6 P# F
surface, or screen and the live pole least likely to arc to ground. The fuse is to be a 3.0 A nontime-delay
+ p5 f3 e* \2 j9 Q [4 s1 q X; u' Qfuse having a voltage rating not less than the rated voltage (Vr) of the thermistor.
/ D7 @1 `# R$ o9 ?0 r6 E5 @9 m4 l18.1.5 Cotton not less than 12.7 mm (1/2 in) thick is to surround a metal screen enclosing the thermistor
: Z6 s, ?) d @9 B7 M* a( jat a distance not more than 12.7 mm from all parts of the thermistor. [9 \2 \* @# h, k
18.1.6 The cotton is to be surgical cotton, such as commonly used for medical purposes. |
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