Glow-wire test apparatus

[Product Purpose]

The Glow-Wire Test Apparatus is equipment used to detect the flame-retardant performance of electrical products such as switches and sockets. The flame-retardant performance of household appliances is generally demonstrated through glow-wire testing, with the aim of evaluating the operational stability of electronic and electrical products. This machine is an upgraded version based on the standard electromechanical glow-wire tester, utilizing PLC programming + touch screen control for more convenient test operation.

The Glow-Wire Test Apparatus heats a nickel-chromium wire of specified material Φ4 mm (U-shaped glow-wire tip) with a high current to the test-specified temperature (300°C to 1000°C), then applies it horizontally to the sample with a specified pressure (0.95N) for 30s. The ignition risk of finished electrical and electronic equipment is determined by whether the sample and underlay ignite or the duration of sustained combustion. After the test, record the glow time, ignition time (Ti), flame extinction time (Te), and flammability index (GWFI).  

[Product Parameters]

Control Method: PLC programming + touch screen control

Timing Device: True color LCD display

Thermocouple: NiCrφ0.5 armored nickel-chromium/nickel-aluminum wire, K-type, imported from Germany, insulated from ground

Glow-Wire Tip: 4.00mm±0.07mm Ni/Cr (>77% Ni/20±1% Cr)

Temperature Sensing Delay: 1.7S

Carriage Speed: Approx. 13mm/S

Temperature Range: 0～1100°C

Sample Pressure: 1±0.2N

Temperature Controller: 16A/D ±0.05%

Pressure Limit Depth: 7mm

Temperature Calibration: 960±15°C

Underlay: Pine board with unit area mass of 12g/㎡~30g/㎡, dimensions 210mm*297mm and 200mm*200mm

Background Color: Black, Volume: 0.5 cubic meters

Sample Distance from Chamber: >120mm

Power Supply: AC220V, 50Hz, ≤500W

Dimensions: 1120×520×1250 (mm), ≥0.5m³ black background, background illumination ≤20Lux

[Precautions]

The power supply for the glow-wire test apparatus should be a stable voltage source (±2% rms). The test circuit should include a current measurement device indicating true RMS with a maximum error within 1%. Due to the high current involved, all circuit connections for the glow-wire must be capable of carrying the corresponding current without affecting performance or long-term circuit stability. Therefore, embedding the glow-wire at connection points with sufficient contact area (generally not less than 60mm² per end) is essential for stable, lossless current and the test itself.

[Instructions for Use]

1. Sample Pretreatment  According to standards, samples and underlay must be conditioned at 15°C to 35°C and 45% to 75% relative humidity for 24 hours before testing. The laboratory should be equipped with a temperature and humidity measuring instrument. If environmental conditions are not met, adjust the atmosphere using air control devices.  

2. Testing  After powering on, heat the glow-wire to a specified high temperature. Apply the test sample to the glow-wire tip with a force of 1N for 30 seconds. After removing the glow-wire, note the flame extinction time and any burning droplets. During the test, place tissue paper on a pine board under the sample to observe if burning droplets ignite the tissue. (For specific test procedures, consult customer service.)  

3. Test Result Evaluation

A. Evaluation of Glow-Wire Flammability Index (GWFI) Results  The sample is considered to have passed the test if it does not ignite or meets the following two conditions:  

1) If the sample's flame or glow extinguishes within 30s after removing the glow-wire.  

2) The wrapped tissue paper does not ignite.  If one or both conditions are not met, repeat the test at a lower temperature with a new sample.  If both conditions are met, repeat the test at a higher temperature with a new sample.  The test should be repeated at the highest temperature where conditions a) and b) are satisfied for the universal circuit breaker sample.  The GWFI is determined as the highest temperature at which three consecutive tests meet conditions a) and b) for the universal circuit breaker.  

B. Evaluation of Glow-Wire Ignition Temperature (GWIT) Results  Determine the ignition temperature of the sample during glow-wire application. Record the test temperature that is 25K higher (30K between 900°C and 960°C) than the highest temperature at which the glow-wire tip does not cause ignition in three consecutive tests as the GWIT.