Why the leakage current of the same sample is in dynamic change is described as follows:
Changes in ambient humidity: An increase in ambient humidity leads to an increase in the conductivity of the sample surface, which leads to an increase in the leakage current.
Changes in temperature: An increase in temperature leads to an increase in ionic motion within the sample, which increases the conductivity and makes the leakage current increase.
Uneven thickness of the sample: Uneven thickness of the sample leads to uneven distribution of the electric field inside the sample, which results in higher current density in some areas, thus increasing the leakage current.
Sample surface contamination: Sample surface contamination will make the conductivity of the sample surface decrease, which will lead to a decrease in leakage current.
Electrode material: different electrode materials also affect the leakage current of the sample. For example, when using stainless steel electrodes, due to the iron element in stainless steel will cause a certain degree of oxidation of the sample, making the leakage current increase.
Leakage Current Test Methods:
I. Introduction Leakage Current Test (Leakage Current Test) is an electrical safety test method, the purpose is to detect whether the leakage current of the electrical equipment exceeds the rated standard, so as to ensure the safety of the user, the non-uniform electric field into a uniform electric field. This test method is generally applied to any type of electrical appliance, including household appliances, commercial electronic equipment and industrial electrical equipment.
Second, the leakage current test principle Leakage current test is based on Ohm's law, the principle is to measure the leakage current of the appliance under standard conditions (i.e., the potential of the two ends of the device is the same and is not subject to the other electric field of the alternating current level is defined as the "standard state"). Leakage current originates from a ***mode mismatch between two electrical devices, resulting in a loss of level equalization within the device, which causes leakage current to occur.
Three, leakage current test equipment Leakage current test requires the use of specialized measuring instruments to accurately measure the leakage current inside the appliance. Among them, the most commonly used two: precision measuring instruments and precision display instruments.
1, precision measuring instruments Precision measuring instruments are generally composed of a measuring amplifier, LC correction circuit and two current sensors, which can accurately measure the leakage current of the device.
2, precision display equipment precision display equipment is a kind of instrument called digital display (DVM), it will leakage current detection data into a digital signal, easy to display the leakage current value of the appliance.
Four, leakage current test process The whole process of leakage current test is as follows:
(1) Connect the measuring instrument;
(2) Read the leakage current of the electrical appliances;
(3) According to the preset standards, determine whether the leakage current size meets the requirements;
(4) If the leakage current exceeds the standard, then it is necessary to carry out the operation of improvement and repair.
V. Summary This article introduces the principle of leakage current testing, leakage current testing equipment and testing process, aims to provide more accurate and fast leakage current testing of electrical appliances for the netizens. Leakage current testing is an important step in the safe use of electricity, and we hope that through this article, netizens can be more cautious and from a safe point of view to buy and use a variety of electrical equipment.