IEC 60695: Difference Between Old And New Eidtion of Glow Wire Test
June 24, 2017
IEC 60695-2-10, Ed 2.0 (2013-04) is a new international standard for glow wire experiment. It has made some modifications on glow wire.
Let's take a look at the new edition standard. What is the difference between the old standard and new standard?
The new version of IEC 60695-2-10, Ed 2.0 (2013-04) has made major modifications on relevant terms and definitions, as well as experimental equipment, and in the specific application, the performance is:
Change Of Test Equipment
First of all, the new standard rule for thermocouple diameter makes the device that uses 0.5mm thermocouple no longer meet the standard requirements.
Second, the new standard is more explicit in the changing range of device that puts pressure on the device, and force is also more precisely required.
Finally, the new standard rules on the diameter of the glow wire(unbent), which requires a higher level of glow wire material before being processed.
Owing to changes of equipment parameters ,the changes of the above parameters need to be paid attention to when checking and measuring equipment. In addition, due to the bending of the process, the material will be deformed, so we should pay special attention to this.
Change Of Operation Steps
Before testing glow wire test, we need to measure glow wire diameter and compare with previous data of last test, if the size reduce to 97.5% of original reading, then change a glow wire.
Although there are requirements for measuring diameter of glow wire in original standard, due to the small limit value, this step is not emphasized in the test. Take standard glow wire diameter as an example, that’s 4.00mm. In new version, the limit is 4 x 0.975 = 3.9 mm. In old standard, the limit is 4 x 0.9 = 3.6 mm. Because the tested samples were non-metallic materials, the hot wire and materials were connected in the test process, however they do not cause damage to the glow wire itself.That’s to say,the diameter wasn’t reduced. Only when after testing, will the steel brush used in the process of cleaning the residue on the glow wire head do some damage to the glow wire.
In accordance with the requirements of the new standards, the equipment and program files involved in the standard have been revised. Through the measurement and observation lasting one year,
the steel brush brushes the glow wire once a week. After each brush, measure the diameter of glow wire.Because each time the force is inconsistent, one person measures it at a same location.After 10 times ,its diameter is measure to reduce by 0.02 mm (compared with firstly measured value). The reduction was 0.03 mm after 20 times. Subsequently, due to the damage of the thermocouple, clean the hole of glowwire,replace the thermocouple and continue to measure thermocouple diameter. Finally, the thermocouple is damaged, because it cannot clean the holes,the glow wire needs to be replaced.
The implementation of the new standard has led to a great change in the test equipment and test operation.