GB/T 2424.22-1986 Basic environmental test procedures for electrical and electronic products Guidelines for temperature (low temperature, high temperature) and vibration (sinusoidal) comprehensive tests GB/T2424.22-1986 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Basic environmental testing procedures forelectric and electronic productsGuidance for combined temperature (cold and heat) vibration (sinusoidal) testsUDC 621.3: 620.1
GB 2424.22-86
This standard is equivalent to the international standard IEC68-2-53 (1984) "Basic environmental testing procedures Part 2: Guidelines for tests Z/AFc and Z/BFc: Combined temperature (cold and dry heat) and vibration (sinusoidal) tests". Examples of test objects are added to the standard, and it is explained that heat exchange between the vibration table and the temperature test chamber should be avoided in the design of comprehensive environmental test equipment, which is not only to keep the vibration table in good working performance, but also to keep the temperature chamber in good working performance. 1 General description of test design
The temperature (low temperature, high temperature) and vibration (sinusoidal) comprehensive test method is formulated according to GB2423.1-81 Test A: "Low temperature test method", GB2423.2-81 Test B: "High temperature test method", GB2423.10-81 Test Fc: "Vibration (sinusoidal) test method". Therefore, the basic test principles described in GB2424.1-81 "High temperature and low temperature test guide" and GB2424.7-81 "Vibration (sinusoidal) test guide" are also applicable to this comprehensive test. According to the test of heat dissipation test samples in low and high temperature tests, it is stipulated that the influence of "free air conditions" should be simulated, that is, the air movement in infinite space is only affected by the heat dissipation test sample itself, and the radiant heat of the test sample is completely absorbed by the surrounding air. At the same time, it is suggested that it is best to use a test chamber without forced circulation for testing. However, in the temperature and vibration comprehensive test, a test chamber with forced pursuit circulation is required to test the heat dissipation test sample. The reason is: a. In order to remove the heat generated by the vibration table. b. The air below the test sample cannot circulate, and the vibration table disturbs the free convection in the test chamber. The test of non-heat dissipation test samples is carried out according to the normal test procedure. For the test of heat dissipation test samples, in order to ensure the correctness of the test, the following test procedure is specified: Step 1: When the test sample is subjected to the ambient temperature specified in the test under "free air conditions", an inspection should be carried out to determine the temperature value of the hottest point on the surface of the test sample:
Step 2: Put the test sample into the comprehensive test chamber, turn on the air circulation system, adjust the chamber temperature, and use the temperature of the hottest point on the surface of the test sample determined in the first step as the temperature monitoring point, and then carry out the test according to the normal procedure. Using the ambient temperature correction calculation chart in the appendix of GB2423.1--81 low temperature test and the ambient temperature correction calculation chart in Appendix 2 of GB2423.2-81 high temperature test, the temperature value of the hottest point on the surface of the test sample can be determined at the test room temperature. Before the test sample is subjected to the temperature and vibration combined test, a single sinusoidal vibration and temperature test check is first carried out. This can avoid the need for expensive combined tests on the same test samples that cannot withstand even a single environment or lose their ability to work in a single environment.
Published by the National Bureau of Standards on July 31, 1986
Implementation on August 1, 1987
2 Environmental Impact
GB2424.22-86
The combined effects of temperature and vibration on the test sample may produce the following effects: a. Changes in the basic material properties of the test sample caused by high and low temperatures increase the risk of degradation of the test sample in a vibration environment. If the material changes caused by temperature are not permanent changes, the combined effects of temperature and vibration must be used to expose this degradation. Equipment containing a large number of materials interconnected, and test samples including viscoelastic and elastic materials, such as electric motors, are particularly sensitive to this combined effect.
b. Under extreme temperature conditions, the resonant frequency of the test sample and its accessories, as well as the vibration transmission characteristics, will change significantly. For example, for test samples with anti-vibration devices under low temperature conditions, especially test samples using rubber shock absorbers, this effect is very obvious. c. The combined effect of temperature and vibration has a greater impact on the explosive release device and connecting devices, so these devices are widely used in this test. For example, this test is carried out on rockets and their related accessories to expose problems. 3 Test equipment
The test equipment must meet the requirements of "test equipment" in the high temperature, low temperature, and vibration (sinusoidal) test methods, and the temperature test chamber wall should have a high radiation coefficient (greater than 0.7). Commonly used temperature and vibration comprehensive test equipment, the structural form is: a: The vibration table extends into the temperature test chamber (see the figure below). Temperature monitoring point
Test sample
Vibration monitoring point
Vibration table
Temperature test chamber wall
Typical layout of the test sample during the test b, install a moving table in the temperature test chamber. For this test, heat conduction between the moving table and the test chamber must be avoided, because this heat conduction will reduce the performance of the vibration table and the temperature test chamber. For this reason, there should be good thermal insulation between the test sample and the vibration table. The usual method is to add a layer of suitable insulation material (or equivalent pad) between the test sample and the vibration table. However, it should be noted that the selected insulation material cannot reduce the rigidity required for installation. In some cases, especially when testing at higher frequencies, it is more appropriate to use ceramic materials as insulation materials. It must also be noted that any device (such as a partition) used to thermally insulate the vibration table from the test box should not usually transmit excessive movement, and there should be no mechanical coupling between the vibration table and the test box, because the excitation it generates may damage the structure of the test box. 4 Environmental parameters and matters to be noted when measuring 4.1 Temperature measurement
The temperature sensor used for monitoring can be subjected to high vibration levels, so the temperature sensing element attached to the monitoring point must be: a. Firm throughout the test process. b. Light weight so that it will not change the dynamic characteristics of the attached monitoring point, and the additional effect of the connecting cable should be minimized. 4.2 Vibration measurementbZxz.net
GB2424.22—86
The handling sensor and the connecting cable must be suitable for the specified test temperature. They must be calibrated at the test temperature. It should be noted that the physical properties of the connecting material (such as adhesive) used to attach the accelerometer to the structure should not change at the specified test temperature.
Additional remarks:
This standard is proposed by the National Technical Committee for Environmental Conditions and Environmental Testing of Electrical and Electronic Products. This standard was drafted by the Temperature/Vibration (Sinusoidal) Comprehensive Test Working Group of the "Environmental Standardization Committee". 623
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