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请问如下这个测试怎么做啊# [+ D$ K7 ?! M! W
18 Limited Short-Circuit Test
; K/ _# j6 b6 B4 a! c18.1 General
# N" T4 {7 g. a, e4 X; Q; [18.1.1 Following the test specified in 18.2.1 or 18.3.1, a thermistor shall:
% Q: ]6 U* U/ ^$ X8 |1 Q) W) Ya) Comply with the requirements in 11.1.2 or be in a permanently high resistance state; and
- t! X! [% w* m, J4 j% K5 g: bb) Complete the test without igniting the cotton indicator or opening the ground fuse described in
9 Y0 [& ~/ [1 G/ L2 l18.1.4 and 18.1.5.$ ~ k3 b8 [8 l1 Z8 T
18.1.2 When the results of the Limited Short-Circuit Test on the thermistor itself comply with 18.1.1, the7 G6 \: w+ M0 p$ O1 Z
test is not required to be repeated during the investigation of the end product.8 o0 T1 s. C/ N; u
18.1.3 Three samples of a control thermistor are to be subjected to this test. The test is to be conducted6 Y( c2 A. L9 ^0 `% G
at rated voltage (Vr).
$ P( s2 ^& h: ?18.1.4 A ground fuse is to be connected between the metal enclosure, metal mounting surface, or metal
. P/ R* ?$ \1 y/ Bscreen described in 18.1.5 and the unswitched line to indicate an arc-over to the enclosure or mounting7 ^" o0 j' S8 E' H% Z, a7 [8 p
surface. Where each line is switched, the fuse is to be connected between the enclosure, mounting C2 o, g) j" |+ g3 L2 K6 N
surface, or screen and the live pole least likely to arc to ground. The fuse is to be a 3.0 A nontime-delay( w$ E( e& @# J- G" j' Q- E
fuse having a voltage rating not less than the rated voltage (Vr) of the thermistor.- a2 ~! w# q- b' O
18.1.5 Cotton not less than 12.7 mm (1/2 in) thick is to surround a metal screen enclosing the thermistor' U! L2 H) K0 |5 E
at a distance not more than 12.7 mm from all parts of the thermistor.
) w+ X1 \! @* q/ b/ X+ t7 X, q18.1.6 The cotton is to be surgical cotton, such as commonly used for medical purposes. |
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