PTC UL1434标准
请问如下这个测试怎么做啊18 Limited Short-Circuit Test
18.1 General
18.1.1 Following the test specified in 18.2.1 or 18.3.1, a thermistor shall:
a) Comply with the requirements in 11.1.2 or be in a permanently high resistance state; and
b) Complete the test without igniting the cotton indicator or opening the ground fuse described in
18.1.4 and 18.1.5.
18.1.2 When the results of the Limited Short-Circuit Test on the thermistor itself comply with 18.1.1, the
test is not required to be repeated during the investigation of the end product.
18.1.3 Three samples of a control thermistor are to be subjected to this test. The test is to be conducted
at rated voltage (Vr).
18.1.4 A ground fuse is to be connected between the metal enclosure, metal mounting surface, or metal
screen described in 18.1.5 and the unswitched line to indicate an arc-over to the enclosure or mounting
surface. Where each line is switched, the fuse is to be connected between the enclosure, mounting
surface, or screen and the live pole least likely to arc to ground. The fuse is to be a 3.0 A nontime-delay
fuse having a voltage rating not less than the rated voltage (Vr) of the thermistor.
18.1.5 Cotton not less than 12.7 mm (1/2 in) thick is to surround a metal screen enclosing the thermistor
at a distance not more than 12.7 mm from all parts of the thermistor.
18.1.6 The cotton is to be surgical cotton, such as commonly used for medical purposes.
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