Definition
The arc resistance tester is a special testing equipment used to evaluate the resistance of solid insulation materials under the action of high-voltage and low-current arcing. The instrument measures the time it takes for the surface surface to form a conductive path or the voltage level it withstands by simulating the arcing phenomenon of surface leakage that may occur in electrical equipment, so as to judge the quality of its insulation properties. This test is of great significance to ensure the safety and reliability of products such as power equipment, electronic components, and household appliances.
Principle
The basic principle of arc resistance test is to apply periodic or continuous high-voltage and low-current arcs on the surface of the material, so that the surface of the material gradually carbonizes, cracks, and finally forms conductive channels. During the test, the arc generated between the electrodes will act on the surface of the specimen, leading to local thermal decomposition and electrocorrosion of the insulating material. The core of the instrument is to precisely control the application time, interval, current and voltage waveform of the arc, and automatically detect the failure point of the material. Material failure is usually defined as the continuous arc penetrating the surface of the material to form a stable conductive pathway, and the time recorded by the instrument is the arc resistance time, and the relationship can be expressed as follows: the resistance performance is positively correlated with the failure time.
Measurement method
The measurement methods of arc resistance test are mainly based on international and domestic standards, such as IEC 61621, ASTM D495 and GB/T 1411. During testing, a flat specimen is placed under an electrode, usually made of tungsten or stainless steel, and maintained with the specified spacing and pressure. The test procedure is generally divided into phases that gradually increase the severity of the arc, such as transitioning from low-current intermittent arcing to higher-current continuous arcing. The operator sets parameters such as voltage (typically 12.5 kV), current (e.g., 10 mA to 40 mA), and arc on/off cycles, and the instrument automatically performs the test and records the total time from start to failure. The entire process is carried out under standard environmental conditions to ensure comparable results.
Influencing factors
The results of the arc resistance test are affected by a variety of factors. The properties of the material itself, such as chemical composition, filler type, surface roughness, and thickness, can directly affect its carbonization rate and arc resistance. Environmental conditions such as temperature and humidity may alter the surface resistance of the material, thereby affecting the stability of the arc. Test parameter settings, including electrode shape, spacing, arc current, and voltage waveform, must strictly follow standards, and any deviation may cause data fluctuations. In addition, cleanliness and pretreatment during sample preparation also play a role in the results, so standardized operating procedures are the basis for ensuring measurement accuracy.
Application
Arc resistance testers are widely used in power, electronics, automotive, aerospace and other industries. In the field of electric power, it is used to evaluate the arc resistance of insulators, switchgear components and transformer materials; in the electronics industry, it is used to test the reliability of circuit board substrates and packaging materials; Ignition system components in automobiles and insulation components in new energy vehicles are also often required to pass this test. In addition, the insulation materials of household appliances and lighting equipment also rely on arc resistance tests to ensure safety in use. This test provides critical data for product development, quality control, and standard compliance verification.
Selection
When choosing an arc tester, it is necessary to consider multiple aspects. First, the instrument should meet the requirements of the target test standard, with corresponding voltage and current range and program control functions. Secondly, pay attention to its safety design, such as protective covers, emergency stop devices, and grounding protection. Automation and data logging capabilities are also important factors, as efficient equipment reduces human error and improves test efficiency. The user interface should be intuitive and easy to use, making it easy to set parameters and analyze results. In addition, consider the maintenance needs of the instrument and the technical support services of the supplier to ensure long-term stable operation. The final selection should be based on the actual test needs, budget, and laboratory conditions.