The main elements of the influence or resistance ratio test are:
a. Ambient temperature and humidity
The resistance value of a typical material decreases as the ambient temperature and humidity increase. For the opposite, the external resistance (ratio) is sensitive to ambient humidity. The bulk resistance (ratio) is more sensitive to temperature. The humidity increases and the appearance of leakage increases. Body conductance will also increase. When the temperature rises, the behavioral velocity ratio of the carrier is faster, and the absorption current and the electrical conductivity of the dielectric material increase in response. According to the material report, the resistance of the Xinjiang UPS is only 20 C at 70 C. 10%. Therefore, when measuring the resistance of the material, it is necessary to indicate the temperature and humidity that the sample and the environment can offset.
b. test
(Electrical Field Strength) The resistance (ratio) value of a dielectric material generally cannot be kept static over a wide range of voltages, ie Ohm’s law is not fast enough. In a normal temperature environment, in the lower voltage range, the electrically conductive flow increases linearly with the addition of additional voltage, and the resistance value of the material remains static. After the excessive voltage has passed, the ionization behavior is given. The increase in the electrical conductivity flow is much faster than the increase in the test voltage, and the resistance value of the material appears to drop rapidly. This shows that things are going on. The higher the test voltage, the lower the resistance of the material. There is a large difference in the possibility of resistance values of the materials obtained by testing under two voltages. The value is that the determining element that causes the material resistance value to change is the electric field strength at the time of testing, and the resistance or resistance ratio is tested instead of the test voltage. For the test voltages that are connected, if the distance between the test electrodes is the same, the test of the material resistance ratio will be the same. In fact, the main elements of the resistance or resistance ratio test.
c. Test period
When the measured material is pressed with the inevitable high voltage, the current on the material to be tested is not instantaneously reached a fixed value, Jilin Shant UPS. Instead, there is a decay process. you know. At the synchronization of the pressure, the flow current is excessively charged, and then the suction current is reduced for a long period of time, and finally a relatively constant electrical conduction flow is achieved. The higher the measured resistance value, the longer the period of offsetting is achieved. look. So take a look at the technical text. In order to accurately read the measured resistance value. The value should be read after the fixed setting or the reading after 1 minute of pressing. Extraordinary. The resistance value of high insulation materials is also related to the history of charging. Have a look. To properly evaluate the electrostatic properties of the material, you know. When holding a resistance (ratio) test on a material, it should be the first to dispose of it. You can see the main elements of the resistance or resistance ratio test. And let stand for a certain period of time, you know the resistance. It can take 5 minutes during the rest period, and then test according to the test procedure. In general, For the testing of a material, at least 3 to 5 samples should be randomly selected for testing, and the uniform value should be used as a test. .
d. Test equipment leakage
In the test, the wiring with low insulation resistance in the line often fails to conform to the sample to be tested and the sampling resistance, which has a great influence on the possibility of measuring the solidity. To this end: in order to reduce the measurement error, the security technology should be selected to install the defending semiconductor on the line with large current, so as to eliminate the influence of the stray current on the test. The high voltage line has a certain leakage to the ground in view of the external ionization. Therefore, the high-insulation, large-diameter press-fit wire is selected as the press-out outlet line and the volume is contracted and connected, the tip is reduced, and the corona discharge is eliminated; the insulating material such as polyethylene or PTFE is selected as the test stand and the support body, Fortunately, the test value is low due to the reason of this category.
e. External interference
After the high-insulation material is applied with a high-voltage voltage, the current flowing through the sample is very small, and is highly susceptible to external interference, resulting in a large test error. The thermoelectric potential and the contact potential are generally small and can be neglected; the electrolytic potential is mainly caused by the contact of the wet sample with two kinds of metals, probably unless it is 20mV, and the static humidity is required to be low in the static test. When testing in a dry environment, Eliminate the electrolysis potential. Therefore, the external interference is mainly the coupling of stray current or the potential of electrostatic induction. When the test current is less than 10-10A or the resistance exceeds 1011 ohms; the test sample, test electrode and test system should adopt strict shielding measures to eliminate the influence of external interference.
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