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　　　　　　　　　　　Wazau 热丝引燃测试仪

热丝引燃测试仪满足EN60950等相关标准，进行试样燃烧性的描述.一个热丝将试样环绕5圈加热，直到样品被点燃或者加热超过120秒.

热丝引燃测试仪介绍：

The Hot Wire Ignition Test reference to EN60950 and other relevant standards

This devices serves the characterization of the ignitibility of samples.

A heating wire is wrapped around a sample five complete turns and heated up.

The test is continued until the specimen ignites or after 120 s have passed

1.Setup

Before using the device for the first time the power cord must be connected to the power supply. The voltage input for the supply voltage is an universal input for voltages ranging from 85 – 264 VAC （47 – 63 Hz）. The device is turnt on by means of the main switch on the rear side. The maximum voltage on the heating wire is 11.5 V with a maximum current of 10 A. The timer is limited to 120 s.

2.Test winding:

A 250 mm ± 5 mm length of nichrome wire （nominal composition 80% nickel, 20% chromium, iron-free） of approximay 0.5 mm diameter and having a cold resistance of 5,28 Ω/m is used.

3.Samples:

Five samples of each material are tested. The samples are 130 mm long minimum by 13 mm wide and of a uniform thickness. Edges are to be free from burrs, fins,etc

4.Conducting a test

Turn on the device on the rear side. The device is now in a stop mode with no voltage applied on the wire connections （picture 1）.

Take the supplied wire according to EN 60950 and make it 250 mm ± 5 mm long. The wire has to be connected in a straight length to the wire connections （picture 2）. Push the button START and adjust the voltage by means of the potentiometer to the desired value. The power dissipation of the wire must be 0.26 W/mm ± 4% for a period of 8 – 12 s （picture 3）. Once this step is completed push the button STOP and DO NOT change the voltage anymore by means of the potentiometer!!

Wire: l = 250 mm

     R = 5.28 Ω/m

P = 0.26 W/mm           R = 5.28 Ω/m

P = 0.26 W/mm x 250 mm  R = 5.28 Ω / 4

P = 65 W                R = 1.32 Ω

U = √ P x                R I = P / U

U = √ 65 W x 1.32 Ω       I = 65 W / 6.3 V

U = 9.3 V                I = 7 A

After cooling, the wire is wrapped around a sample to form five complete turns spaced 6 mm apart.

The specimen has to be mounted to the device using the milling screws （picture 4）. Start the test by pushing the START button with the dissipation power tested before of 0,26 W/mm ± 4% in the wire. The test is continued until the specimen ignites or after 120 s have passed. The device turns off automatically after 120 s. The test can be terminated before 120 s have passed by pushing the STOP button.

The time passed since starting the test is displayed on the display TIME （picture 5）.

For specimens that melt through the wire without ignition, the test is discontinued when the specimen is no longer in intimate contact with all five turns of the wire.

The test is repeated on the remaining specimens.

5.Compliance criterion:

The average ignition time of the specimens tested shall not be less than 15 s.