Insulation withstand voltage tester is a pressure test equipment designed according to the latest national electric power industry standards. It is used to test the insulation strength of various electrical products, electrical components, insulating materials, etc. under specified voltage to assess the insulation level of the product. Found the insulation defect of the test article and measured the ability of overvoltage.
The insulation withstand voltage tester on the production line is used very frequently, especially the test line and test fixture are often in active state, which is easy to cause the inner core wire to break open, and is generally difficult to find. As long as there is an open circuit at any point in the loop, the high voltage output from the insulation withstand tester cannot be actually added to the object to be tested. These reasons will cause the set high voltage not actually added to the measured object during the withstand voltage test. Naturally, the current flowing through the measured object is almost zero, because it does not exceed the upper limit of the insulation withstand tester. The set value, so the instrument will give a test pass, suggesting that the insulation is qualified. But the test data in this case is not true. If the measured object at this time happens to be defective in insulation performance, it will cause serious misjudgment.
How to avoid the occurrence of misjudgment
In the withstand voltage test, we all think that the smaller the leakage current, the better, so many operators do not set the lower limit current (generally the factory value is set to zero). If the above situation occurs, there is a misjudgment. The possibility is that a reasonable lower limit can be used to solve this situation. When the voltage tester is not connected to the object under test, the air test is performed. At this time, there is a small virtual current. We only need to set the lower limit current to be slightly higher than the air test current value. When the test circuit has an open circuit (such as the operator fails to connect the measured object or the test line is short-slit, etc.), since the leakage current value is less than the lower limit setting, the insulation withstand voltage tester will give an alarm. Then we need to check whether there is an open circuit on the test line or the connection to ensure the effectiveness of the product test. This problem also exists in the insulation resistance test. For general products, it is always considered that the greater the insulation resistance of the product, the more satisfactory it is. However, if the open circuit between the insulation withstand tester and the measured object is also present, the same misjudgment may occur. At this point we can avoid this by setting the upper limit of the insulation resistance.
How to determine the situation indicated by the instrument alarm
A well-functioning insulation withstand voltage tester should provide sufficient information for the operator. When the instrument is alarmed, it can quickly provide some information to the operator to improve the efficiency of production.