Dongguan Langyi Electromechanical Technology Co., Ltd.

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Why the withstand voltage test cannot be repeated

[Guide] The withstand voltage test is the motor winding production and processing process, as well as the whole machine product test, the test of the motor insulation performance test, under the specified conditions without breakdown, as the qualification judgment standard.


When a customer visited the factory, he raised the question about whether the motor product can be repeatedly tested for withstand voltage. This question was also asked by many customers who use motors.


The withstand voltage test is the process of motor winding production and processing, and the testing of the insulation performance of the motor during the test of the whole machine product, and it will not be broken down under the specified conditions as the qualification judgment standard.


In order to ensure that the insulation performance of the motor meets the requirements, in addition to selecting suitable electromagnetic wires and insulating materials, it must also have reliable process guarantees, such as processing protection, suitable tooling, good paint dipping equipment, and suitable process parameters.


Taking the high-voltage motor winding as an example, most motor manufacturers will conduct a turn-to-turn and withstand voltage test on each coil. Before the paint is dipped, the winding iron core is tested for the complete machine during the inspection test. This returns to Customers' doubts about the pressure problem.


Objectively speaking, the withstand voltage test is an irreversible and destructive test. Regardless of whether it is a winding or a single coil, it is not recommended to repeat the test on the premise of the necessity of finding the problem. The standard requires lowering the test voltage to minimize the damage to the insulation.


About withstand voltage tester


The withstand voltage tester is an instrument for measuring the strength of withstand voltage. It can intuitively, accurately, quickly, and reliably test the electrical safety performance indicators of various tested objects, such as withstand voltage, breakdown voltage, and leakage current. Withstand voltage tester, you can find the problem and judge the conformity of insulation performance.


● Check the ability of insulation to withstand working voltage or overvoltage.


● Check the quality of electrical equipment insulation manufacturing or maintenance.


● Eliminate the damage to the insulation due to raw materials, processing or transportation, reduce the early failure rate of the product.


● Check the insulation clearance and creepage distance compliance.


Selection principle of withstand voltage test voltage


The best way to determine the test voltage is based on the specifications required for the test. In general, the test voltage is set at twice the rated voltage plus 1000V. For example, the rated voltage of a product is 380V, that is, 2 x 380 + 1000 = 1760 V as the test voltage. Of course, the test voltage will be set differently depending on the level of the insulating layer, and the voltage requirements of different product types are also different.


Why do you often check the integrity of the test circuit?


The pressure tester on the production line is used very frequently, especially the test line, test fixture, etc. are often in active state, which is easy to cause the internal core wire to break and open, and it is generally not easy to find. As long as there is an open circuit at any point in the loop, the high voltage output by the withstand voltage tester cannot be really added to the measured object. These reasons will cause that when the compressive strength test is performed, the set high voltage is not really added to the test object. Naturally, the current flowing through the test object is almost zero at this time, because the upper limit of the pressure tester is not exceeded. Set value, the instrument will give a prompt to pass the test, that the insulation is qualified. But the test data in this case is untrue. If the measured object at this time happens to be defective in insulation performance, it will cause serious misjudgment.




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