Everwide Newsletter
Everwide Newsletter No.304
Date:2019-07-29

Experiment report § Arc resistance tester

Arc resistance test is often referred to as Arc resistance, according to ASTM D495, its full name is "Test of resistance to high-voltage and low-current dry arc of solid electrical insulating materials". Place the test piece on the electrodes 6.35mm apart, and apply a voltage of 12.5kV and an arc current of 10mA. The relationship between the test piece, electrode and the tester is shown in Figure 1, and Figure 2 is the overall view of the instrument. At the beginning, the arc is applied intermittently, such as energizing for 1/4 second and powering off for 1 ¾ seconds. Gradually increase the energization time to continuous power (Figure 3); the current will also gradually increase from 10mA to 40mA. Different test standards such as ASTM D495, IEC 61621, GB 1411-78.. etc., the current intensity and power-on time per minute are not the same, so pay attention to it. The surface of the test piece is affected by the high temperature of the arc, and carbonization occurs first near the electrode (Figure 4). As the arc time increases, black continuous lines are carbonized (Figure 5), the conduction arc disappears, or the test piece ignites and burns (Figure 6)... etc. These all indicate that the test piece has failed. The time for different materials to be destroyed is different, so the arc resistance of the material is evaluated according to the number of seconds of failure. The arc resistance time of pure epoxy resin is about 30-60 seconds, and the formula with a large amount of quartz powder is about 120 seconds.
Author: Miss Lin Jiajing
About Everwide § Passionate July

Summer interns are welcome to register. In addition to visiting the environment, the check-in activity also took a cover photo of the intern handbook in the garden (Figure 1). During the internship, not only can you experience the joys and joys of work, but the R&D staff will also teach students the professional knowledge of instruments and machines (Figure 2). The two-month learning journey, I hope everyone can gain something and return with a rewarding experience. The unwarned firefighting drills held regularly every year are intended to simulate possible situations to respond to emergencies. The weather on the day of the exercise should not be too hot. Otherwise, the sultry feeling of wearing protective clothing is really not to be underestimated (Figure 3). It reminds people of firefighters wearing heavy protective equipment. It must be very hard. Thank you for your effort. Fire brave. Group society depends on mutual assistance, and we are all receiving the favor of many people, don't you think?

Knowledge exchange § What are specific strength and specific modulus?

Specific strength (Specific strength) is the strength divided by the density, which is the strength per unit density, the unit is MPa/(g/cm3). Some materials have the same strength when the test piece of the same shape is used, but the density of the two is quite different, so the difference in specific strength is great. Taking aluminum and stainless steel as examples, the tensile strength of the two is similar, but the former has a density of 2.9 and the latter has a density of 7.9, so the strength is more than 3 times worse. In other words, in the design of the same strength, the weight of aluminum is 1/3 of stainless steel; or in the design of the same weight, the weight of aluminum is 3 times that of stainless steel. Specific modulus (Specific modulus) is the modulus divided by the density, which is the modulus per unit density, the unit is GPa/(g/cm3). The higher the specific modulus of the material, the higher the rigidity of the same part; in other words, the higher the specific modulus, the lighter the weight of the material in the same rigid design.

Bi-weekly strike § Studious Youth 2 strong>

Starting from March this year, "Learning Youth Part2" will be launched. By watching the Japanese TV series "Shitamachi Rocket", think about the advantages and disadvantages of "Tsukuro" and "Everwide" in the film. The content of the activity is the experience of each group of reports and discussions. Participants and consultants Yu Ming and the teacher will all ask questions and give feedback. They will experience the sour and sweet taste of growth in learning. What's valuable is that everyone performs their duties at work and can get together to share and discuss with colleagues in various departments. It is really a great experience. In addition to analyzing what we can do to improve the collective good of the group, we also extend other issues that need to be discussed. For example: What kind of company is Everwide? What kind of employees can make Everwide better? I don't think there is an absolute answer to these questions, but as the saying goes: "Attitude is everything." A flat organization relies on everyone's ability to complete work independently and coordinate with each other. A good working atmosphere requires unity, let us remind each other and move together! During the three-month event, I was most impressed by the whole process of producing briefings: from discussing together and reaching a consensus, the reporter integrated the results of the group, and produced a pre-reported briefing, the group conducted the initial trial report to the final Confirm within the group. Although the tension was broken in the first report, after Mr. Yu’s suggestion and our many practice sessions, the teacher praised everyone for much improvement. To paraphrase Einstein's words: "Insanity: doing the same thing over and over again and expecting different results. What is a madman, is to repeat the same thing and expect different results." Let us work hard together to create, Study happily together and work happily together.
─ Author: Mr. Dan Xinxin

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