This standard specifies the test method for evaluating the durable thermal performance of flexible composite materials for electrical insulation by the coiled tube inspection voltage method. This standard is applicable to flexible composite materials for electrical insulation with a thickness of 0.5 mm or less. JB/T 3730-1999 Test method for evaluating the thermal resistance of flexible composite materials for electrical insulation Coiled tube inspection voltage method JB/T3730-1999 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of Chinabzxz.net
JB/T3730
Lei Liao Jie
1999-08-06 Tea
Ma Fu Shen
Wa Xian Ji Dong
2000-01-01 Small Cable
JB/T37301999
This standard is a revision of JB3730-84 "Test method for evaluation of heat resistance of soft composite materials - Coil inspection voltage method". Compared with JB3730-84, this standard has been revised in the writing format, and the technical content has the following differences: 1 The measurement unit has been modified:
2 According to the provisions of IEC60216, the content related to heat resistance has been deleted; 3 The aging temperature and exposure cycle recommended by JB3730-84 have been revised to the provisions of Table 1 in GBT11026.1; 4 According to the provisions of GB/T11026.1, the procedure for measuring the original breakdown voltage value is changed from taking 10 test points to taking 22 test points; the heat aging test is changed from at least 10 test points per group of samples to at least 1 test point per group. This standard will take effect from the date of implementation and replace JB 3730-84. This standard is proposed and managed by the China Insulation Materials Standardization Technical Committee. This standard was drafted by Guilin Electric Science Research Institute. The drafters of this standard are Hou Jiabie, Liang Xiancai, Wu Xiuyue, Zhang Yisuo, Deng Yingbin, Shao Xihai. This standard was first issued on July 14, 1984, and was first revised in 1999. This standard is entrusted to the National Technical Committee for Standardization of Insulating Materials for interpretation. I
1 Scope
JB/T37301999
JB373084
This standard specifies the test method for evaluating the heat resistance of soft composite materials for electrical insulation by the coiled tube test voltage method. This standard is applicable to soft composite materials for electrical insulation with a thickness of 0.5mm and below. 1 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. When the standard is published, the versions shown are valid. All standards are subject to revision. Parties using the standard are invited to discuss the possibility of using the latest version of the standard. GB/T 1408—1989 GB/T [1026.1—1989] Guide to high-frequency electrical stress test of insulating materials (eqvIEC 60243:1987) Guide to determining the heat resistance of electrical insulating materials General procedure for establishing aging test methods and evaluating test results (eqvJEC 60216—1:1987) IEC 602164—1:1990 Guide to determining the heat resistance of electrical insulating materials Part 4 Aging oven Part 1: Single chamber oven 3 Overview of the method 3.1 In order to simulate the bending force exerted on the insulating materials in the structure of general motors and electrical insulation and the internal stress caused by the inability to shrink freely under the action of heat in the thermal aging test, this standard stipulates the use of coiled tube specimens. 3.2 Use the voltage inspection method to detect the decrease in the electrical strength of the material during the thermal aging process and determine the temperature index (TI) of the material. 4 Sample
The test materials should be the same batch of products that meet the technical requirements of the product. The manufacturing unit should provide complete measured data according to the product standard. 4.1
4.2 Sample structure
The sample structure is shown in Figure 1, which consists of three parts: a) The sample is 400 ml long and 88±1 mm wide. Its long side is the horizontal width of the test material. The short side is the longitudinal space: b) H59 type brass, outer thickness 20±0.1mm, wall thickness about 2mm, length about 400mm, its outer surface should be smooth, roughness is H62 type rise elastic brass ring, its inner diameter is the same as the outer diameter of the cadmium tube, the unfolded size of the brass ring is shown in Figure 2. The brass tube and the brass ring are the two motors for the inspection voltage test. 1999-08-06 tumor
2000-01-01 small cable
Number of samples
JB/T3730
1—Wall thickness 0.4m1m yellow pin ring: 2—Sample: 3—Medium 16/Medium B0 British copper tube; 4—M3 ×12 screw: 5—M3 nut: 6—M3 heat map: 7-M3 Figure 1 Specimen structure (unit: mm)
Figure 2 Brass ring unfolded size (unit: mm) The brass ring fixed on the specimen and the corresponding brass ring constitute a test point. 5.1
Each test material must have at least 11 qualified test points at each test temperature point: 5.3 For composite materials with asymmetric structures, specimens wrapped in both positive and negative directions should generally be prepared. 6 Specimen preparation
Clean the copper ring and copper tube.
6.2 Wrap the cut specimen flatly and tightly on the copper tube"11 0. 4
63 On the outside of the strange tube specimen, put on the knife-edge copper ring at a spacing of about 50mm. The opening of the copper ring should face the overlapping part of the specimen wrapping. Fix the copper ring on the specimen according to the structure in Figure 1. When placing the steel ring, pay attention to: JB/T3730
a) The inner surface of the copper ring should be close to the specimen without leaving any gap. It is best if the steel ring cannot rotate on the coil: b) Put the copper ring in the correct position at one time as much as possible, and do not let the ring rotate back and forth on the coil to avoid scratching the sample: To determine the screening voltage and test voltage
7.1 Determine the screening voltage value
Take 60% of the breakdown voltage value specified in the product standard of the test material as the screening voltage value. For trial products, take 60% of the average measured breakdown voltage as the screening voltage value.
7.2 Determine the inspection voltage positive value (i.e., the end point mark). Take 50% of the breakdown voltage E value specified in the product standard of the test material as the inspection voltage positive value: For trial products, 50% of the average of the measured breakdown voltage can be taken as the inspection voltage value.
Recommendation: The minimum inspection voltage value should not subject the sample to an electric field strength lower than 15MV/m: The maximum inspection voltage value should not subject the sample to an electric field strength higher than 20MV/m:
8 Aging temperature and time
8.1 According to the requirements of Chapter 9 of GB/T11026.1-1989, select three or more different temperatures for aging tests (as shown in Figure 3).
In order to accurately select the aging temperature point, generally before the formal evaluation test, a selective test of the highest test temperature point should be carried out: Life
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Figure 3 Aging temperature-life curve
8.2 It is recommended to use the aging temperature and exposure cycle recommended in Table 1 of GBT11026.1: In order to make the samples at each aging temperature undergo the same treatment, the selected exposure cycle should preferably enable the samples to obtain the median value of the damage time when subjected to about 10 hot and cold cycles
Select the lowest aging temperature point and the thermal life time is greater than 5000h3
9 Test equipment
9.1 Aging oven
JB/T37301999
The aging oven should comply with 1EC 60216-4-1. 9.2 The electrical breakdown test equipment
shall meet the requirements of GB/T1408.
9.2.1 The voltage increase speed is 500VIS, and the voltage is automatically increased from "zero" until the sample breaks down or increases to the specified value. 9.2.2 Adjust the operating current of the overcurrent relay so that the circuit is cut off when the secondary current reaches 30mA: 10 Procedure
10.1 Measure the original breakdown voltage detection
From the prepared samples, randomly select 22 test points of the samples, treat them at a temperature of 23±2℃ and a relative humidity of (50±5)% [hereinafter referred to as normalization conditions) for 6h, and then conduct a breakdown test. Take the half-mean value of the 22 test points as the original breakdown voltage value. During the testing process, if interlayer creepage occurs on the sample, the outer surface of the sample can be tightly wrapped with glass cloth. If creepage still occurs, the width of the sample is widened to 100mm, and 22 test point samples are made for breakdown test. [0.2 Screening test
All samples are treated under normal conditions for 6 hours. Then, a screening voltage test is applied to each test point for 30s, and the number of points that are broken down under the screening voltage is recorded. If more than two test points on a test rod are broken down, the sample should be re-prepared. If 30% of all test points are broken down, the batch of samples cannot be used for evaluation tests.
10.3 Heat aging test
10.3.1. Divide all qualified samples after screening and positive inspection into two or three groups at random according to the predetermined aging temperature points, and obtain at least 11 test points.
103.2 In principle, the aging test of each temperature point should be carried out at the same time. The reference sample should be placed in the middle of the same oven with the test sample for aging comparison test
Note: In order to avoid the loss of samples and effectively use the space, the samples must be placed on the appropriate sample. The distance between the samples in the same layer is about 15mm and the distance between the upper and lower layers is about 100m: 10.3.3 Take out all samples regularly according to the predetermined exposure cycle: After the samples are cooled to room temperature, the samples are subjected to 61 normalization conditions. 10,3,4 Apply 30% of the back voltage test to all test points. The number of points that broke down in the inspection voltage test is recorded as the corresponding number of exposure periods
10.3.5 All samples that passed the inspection voltage test are returned to the original oven for the next exposure cycle of aging test, and this is repeated until all samples are destroyed at this temperature.
10.3.6 The speed of root saw specimen failure can be appropriately changed by changing the exposure cycle. If more than half of the specimens are still damaged by the eighth exposure cycle, the exposure period can be doubled. If 1/3 of the specimens have been damaged in the third period, the exposure period should be doubled or half. 11 Test data processing and determination of temperature index 11.1 Test data processing
11.1.1 Calculate the thermal life of each test point at each aging depth. The thermal life of each test point L is:
JB/T3730
Lt, (P-0.5)
Where: L is the thermal life of the th test point at each aging temperature, h; j is the number of test points at the temperature; t is the exposure cycle time, h;
P is the number of exposure cycles at which the th test point is damaged. In the case of exposure cycle changes, the thermal life of each test point is equal to the cumulative aging time when the bulge occurs minus half of the exposure cycle time when the damage occurs.
11.,1.2 Draw a thermal survival diagram
On a semi-logarithmic coordinate paper, use the logarithm of the time as the vertical coordinate and the inverse of the absolute temperature as the horizontal coordinate to draw a relationship diagram between the thermal life and aging temperature of each test point under each aging humidity. Use the least squares method to find the linear equation between the two and the lower confidence limit. 11.2 Temperature Index (TI)
The temperature index is the Celsius temperature value corresponding to a certain time (usually 20,000b) on the thermal life diagram: For example: The temperature expansion index of a material coil inspection voltage filter is 130, which is recorded as: Coil Inspection Voltage Method II: 130 If the temperature corresponding to other times is taken as the temperature index, this time should be noted. For example, the overflow index corresponding to 30,000h is 125, which is recorded as: Coil inspection voltage method TI30kh: 125. 12 Test report
The test report should include the following items:
a) The name, structure, model and batch number of the test material and reference material specimens; b) The month of the evaluation test;
c) The breakdown voltage value specified in the product standard of the test material and the (velvet) measured breakdown voltage value;) The number of test points where breakdown occurred under the screening electrical inspection; e) List all thermal life data of each test point on each aging temperature card; f) Thermal life diagram ：
g) Temperature index (T1)) For asymmetric composite materials, the above values ​​for the two wrapping directions should generally be given separately: h) Others, such as the time of aging test, abnormal conditions during the test, etc., 5
JB/T3730
880b1230
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