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灼热丝测试说明
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注意:由于测试仪器不同方法可能会有不同,但是原理相同4 c9 N* d0 t$ S+ n9 _6 I
, ~* m( W- T6 _+ ~关键是测试和判定方法。
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如果大家觉得很难懂,再翻译
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Glow Wire : x4 u" r( P; ?! @
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1. Purpose
$ e$ s7 ]5 o2 T+ BGlow-wire test simulates the effect of thermal stresses which may be produced by heat sources such as glowing elements or overloaded resistors, for short periods to assess by a simulation technique the fire hazard.
; D( H0 n1 N$ G0 p0 D2 z2. Scope
+ ~) g7 t7 a& I: f# gGlow-wire test is applicable to electrical equipment, its sub-assemblies and components and to solid electrical insulating materials.
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3. Specimen 9 l7 M! s: W5 ?3 B; h# `& H
If the test cannot be made on the complete sample, a suitable part may be cut from it. Unless otherwise specified in the relevant specification, the test is made on one specimen. In case of doubt with regard to the results of the test, the test is repeated on two further specimens.
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6 l! Y# n5 P" Y5 R/ t2 T7 S4. Preconditioning 9 ]/ \: Q+ l3 o! x! \* s7 k5 a, z
The specimen, the white pinewood board and the tissue paper are stored for 24h in an atmosphere having a temperature 15°C ~ 35°C, and relative humidity 45% ~75% before starting the test.
0 I# O+ H) u, s7 O/ O5. Test procedure & Y4 I5 S* D5 n" K
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5.1 A piece of flat smooth white pinewood board, approximately 10mm thick covered with a wrapping tissue, is positioned at a distance of 200+/-5mm below the place where the glow-wire tip is applied to the specimen.
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; M" J( @% T& s0 n. G& I& J" F5.2 The specimen is positioned on specimen holder so that the surface of specimen in contact with the glow-wire tip is vertical. Keep the tip of glow-wire can only press into specimen 7 mm.+ J2 Z( X; e8 O3 H+ I
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The manual carriage shall be so designed that glow-wire applies a force of 1+/-0.2N to the specimen.
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5.3 Turn on the power supply switch. Adjust the current by the adjust knob to set the glow-wire temp. as specified. When the glow-wire temperature reached the setting value and maintaining at least 60s, the glow-wire is ready for test.
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5.4 Unless otherwise specified in the relevant specification the value of duration ta of application of glow-wire shall be set to 30s using the relevant timer.
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5.5 The specimen is move into contact with the tip of the glow-wire meanwhile the timer (left) start a record for 30s.
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3 j# `# N. f9 K; P% ?* P! x5.6 After the glow-wire is applied to the specimen for 30s, the specimen shall be removed back to the left. In case of ignition of the specimen when flame distinguishes push the relevant button and pay attention to observe and record:0 q% q4 r& A3 o) R8 T' {
) \4 _ o, C' N; @6 X, d" X• The duration from the beginning of tip application up to the time at which the specimen ignites.
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• The duration (Te) from the beginning of tip application up to the time when the flames extinguishes during or after the period of application.
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• The maximum height of any flame rounded off to within the next 5mm but disregarding the start of the ignition, which may produce a high flame for a period of approximately 1s. ) G7 P$ ?) D2 c0 C, {
, {3 z* A" L$ `: ^• Any burning of the tissue paper or any scorching of the pinewood board.
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5.7 Make sure the current adjusting wheel back to zero position, and turn the power off to finish the test. Then use the fan to extract the smoking.% r& f% |! v6 F4 F
6. Evaluation of test results 1 o p; R2 X A' z( \, g2 q, S/ z
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If one of the following situations applies, the specimen is considered to have satisfactorily withstood the glow-wire test.
~* B& V [2 a' E2 b• There is no flame and no glowing of the specimen. ! ^' j# j5 L Z% f1 b- j5 E
6 Z7 j2 H( |5 v$ I( U( T• Flames or glowing of the specimen and the layer below extinguishes within 30s after the removal of glow-wire, that is te 小于等于 ta +30s, There is neither ignition of the wrapping tissue nor scorching of the pinewood board. - P2 [# k1 T" S7 g" G0 S4 J
4 [( k7 A3 o' U- T+ [8 @ m4 p7. Maintenance of apparatus 4 }+ M- P+ z6 |. _% R; o
. h S! {2 v! D" q7.1 After each test, it is necessary to clean any residue of previously tested material from the tip of the glow-wire, for example by means of a steel wire brush. ' a4 d. ^6 t6 l- `* ^ G
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7.2 Before test shall check the specimen automatically-moving system, whether or not it is normal. |
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