Principle of leakage current tester_How to use leakage current tester_Precautions for using leakage current tester

　　The leakage current tester is designed according to international and domestic safety standards such as IEC, ISO, BS, UL, JIS, etc. It is suitable for testing the safety leakage current of various household appliances, power supplies, cables, terminal blocks, high and low voltage bakelite appliances, switches, power plugs, motors, DVD players, washing machines, centrifugal dehydrators, microwave ovens, electric ovens, electric hot pots, televisions, electric fans, medical instruments, electronic instruments and high-voltage systems. It is also an indispensable leakage current detection equipment for scientific research laboratories and technical supervision departments.

　　Leakage Current Tester Principle

　　The principle of leakage current measurement is basically the same as that of insulation resistance. Insulation resistance measurement is actually a leakage current, but it is expressed in the form of resistance. However, the regular measurement of leakage current applies an AC voltage, so the leakage current contains the capacitive component current.

　　When conducting a withstand voltage test, in order to protect the test equipment and test according to the specified technical indicators, it is also necessary to determine the maximum current value allowed to flow through the device under test (insulating material) without destroying the device under test (insulating material) at the highest electric field strength. This current is usually also called leakage current, but this method is only used in the above specific occasions. Please pay attention to the difference.

　　Leakage current is actually the current flowing through the insulation part of an electrical circuit or device when there is no fault and no voltage applied. Therefore, it is one of the important indicators to measure the insulation quality of electrical appliances and is also the main indicator of product safety performance.

　　The principle of the leakage current tester is to limit the leakage current to a very small value, which plays an important role in improving the safety performance of the product.

　　The leakage current tester is used to measure the leakage current unrelated to work generated by the working power supply (or other power supply) of the electrical appliance through the insulation or distributed parameter impedance. Its input impedance simulates the impedance of the human body.

　　How to use the leakage current tester

　　1. Plug in the power supply, turn on the power switch, and the power indicator light is on;

　　2. Select the power range and press the required current button;

　　3. Select the test time;

　　4. Select the leakage current alarm value;

　　5. Connect the object to be tested to the measuring end, start the instrument, raise the test voltage to 1.06 times (or 1.1 times) the rated working voltage of the object to be tested, switch the phase conversion switch, read the secondary readings respectively, and select the leakage current value with the larger value. When the conversion switch K is connected to the neutral line, the tester samples the leakage current between the neutral line and the shell; when K is connected to the phase line, the leakage current between the phase line and the shell is tested. It must be noted that: when K is connected to the neutral line or K is connected to the phase line, the leakage current is not necessarily the same. This is because the location of the insulation weakness of household appliances is random. Therefore, the leakage current test should be carried out by converting the polarity through K, and the larger value should be taken as the leakage current value of the electric heating appliance to be tested.

　　Precautions for using leakage current tester

　　1. The impact of the environment on the test data should be minimized. The temperature, humidity and contamination of the insulation surface of the test environment have a great influence on the leakage current. When the temperature is high, the humidity is high, and the insulation surface is seriously contaminated, the measured leakage current value is large.

　　2. When measuring leakage current at working temperature, if the tested device is not powered by an isolation transformer, the tested device should be insulated from the ground by an insulating pad with reliable insulation performance. Otherwise, part of the leakage current will flow directly through the ground instead of the instrument, affecting the accuracy of the test data.

　　3. Leakage current measurement is carried out with electricity, and the shell of the tested electrical appliance is charged. Therefore, testers must pay attention to safety, and various laboratories should formulate safety operating procedures. Before the current is cut off, the tested electrical appliance must not be touched.