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Method for inspection of three-layer insulation wires

Release time:

2023-07-26 08:43

1. Winding test of three-layer insulation wire: Take a sample with a length of at least about 305mm and wind it 10 times on a circular rod equivalent to the outer diameter of the sample at a speed of 1-3 turns/second. The tension borne by the wire during winding is just enough to make the wire in close contact with the circular rod, and it should be noted that there should be no elongation of the sample. After winding, the sample should be visually inspected and there should be no deep or conductor cracks in the insulation layer.
2. Breaking test of three-layer insulation wire: Take a 200mm sample to break, and the sample after breaking should not have exposed copper at the fracture surface. The sample with extended fracture surface should not have tubular detachment when subjected to 10mm ring cutting.
3. Thermal shock test of three-layer insulated wire. Place the above sample in a constant temperature oven specified at 155 ℃ for 30 minutes, and then remove the sample from the oven. After it cools to room temperature, observe its surface with a 10x magnifying glass, and the insulation must not have cracks.
4. Softening and breakdown test of three-layer insulation wire: According to the requirements of the fourth test method in the national standard GB/T4074.6-1999, there is no breakdown at a temperature of 170 ℃ for 2 minutes.
5. Soldering test for three-layer insulated wire: After immersing the sample in a soldering bath at 420 ± 5 ℃ for 2 seconds, the surface of the tinned wire should be smooth and free of pinholes.
6. Voltage withstand test of three-layer insulation wire: Take a straight sample with a length of 305mm, clamp the sample with two copper foils with a length of 152mm up and down, and leave the length of the sample outside the two ends of the copper foil length direction equal. Apply the test voltage between the two copper foils and the sample. The test voltage is 3000V, the leakage current is 2mA, and the test time is 1 minute. After applying the voltage according to the above method for 1 minute, the sample should not break down.
7. Surface quality of three-layer insulation wire: The surface of high-frequency high-voltage winding wire should be smooth and uniform in color, and there should be no defects that affect the performance of high-frequency high-voltage winding wire.
8. Inspection rules for three-layer insulation wire: Each roll of product must undergo tests such as appearance, size, elongation, flexibility and adhesion, and withstand voltage test, and be recorded. Each batch of products leaving the factory shall undergo all project tests and records specified in this standard according to the sampling ratio agreed upon by both the supply and demand parties. If requested by the demand party, they can be provided to the other party. Except for non-conforming items in appearance, size, and elongation that can be downgraded for use through negotiation with the purchaser, any other non-conforming items found will not be retested and will be treated as non-conforming products.