This standard specifies the test procedures, severity levels and basic requirements for test chambers (rooms) for cyclic damp heat tests. This standard is applicable to determining the adaptability of electrical and electronic products or materials to use and store under damp heat conditions with temperature cycles and condensation on the product surface. GB/T 2423.4-1993 Basic environmental test procedures for electrical and electronic products Test Db: Cyclic damp heat test method GB/T2423.4-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Basic enviroamental testing proceduresfor electric and electronic productsTest Db: Danp heat ,cyclic
GB/T 2423.4—93
Replaces GB 2423.4B1
This standard is equivalent to TEC68-2-30≤Basic Environmental Testing Procedures Test Db and Guidelines: Danp heat ,cyclic (12+12h cycle)" (Second Edition in 1980) and the first original in 1985. 1 Subject content and scope of application
This standard specifies the test procedures, severity levels and basic requirements for test chambers (rooms) of the alternating heat avoidance test. This standard is applicable to determine the adaptability of electrical and electronic products or materials to be used and stored under the conditions of temperature cycling and damp heat with dew on the product surface.
2 Referenced standards
GB2421 General rules for basic environmental test procedures for electrical and electronic products GB2422 Terminology of basic environmental test procedures for electrical and electronic products GB2424.2 Guidelines for damp heat test for basic environmental test procedures for electrical and electronic products 3 Requirements for test chambers (rooms)
3.1 Sensors for monitoring temperature and humidity conditions should be installed in the working space. 3.2 The temperature in the working space should be able to cycle between 25±3℃ and the selected high temperature according to the instructions in Chapter 5 and Figure 2; the temperature change rate and temperature tolerance should meet the requirements of Chapter 5 and Figure 2. 3.3 The relative humidity in the working space should meet the requirements of Article 5.2.3 and Figure 2. 3.4 The temperature and humidity in the working space should be uniform and consistent with the conditions at the temperature sensor as much as possible. 3.5 The radiant heat from the heating element of the test equipment shall not act directly on the test sample. 3.6 When using the humidification method that generates humidity by direct contact with water, the resistivity of the water during the test shall be maintained at not less than 5002·m. 3.7 Condensed water shall be continuously discharged outside the workroom and shall not be used again without purification. 3.8 Condensation on the inner wall and top of the test box (room) should not drip onto the test sample. 3.9 The performance and electrical load of the test sample should not significantly affect the temperature and humidity conditions in the working space. 4 Severity level
4.1 The test severity level is determined by the combination of high temperature and test cycle number. 4.2 The relevant standards should select the severity level from the following combinations: High temperature: 40℃
Test cycle: 2, 6, 12, 21, 56d.Www.bzxZ.net
Approved by the State Administration of Technical Supervision on November 19, 1993 and implemented on July 1, 1994
b. High overflow temperature: 55℃
Test cycle: 1, 2, 6 d
5 Test procedure
5.1 Initial test
GB/T 2423.4-93
In accordance with the provisions of relevant standards, conduct an appearance inspection of the test samples and test their electrical and mechanical properties. 5.2 Conditional test
5.2.1 Place the unpackaged, non-powered test samples in the working space of the test box (chamber) in the "ready to use" state in their normal working position or in the state specified by relevant standards. If the test sample is installed in a special way and a mounting rack is required, the thermal conductivity of the sample rack should be as low as possible so that the test sample is actually insulated.
5.2.2 Under the conditions of a temperature of 25±3°C and a relative humidity of 45% to 75%, allow the test sample to reach temperature stability. Afterwards, increase the relative humidity in the working space to not less than 95% within 1 hour (see Figure 1). Note: Temperature stability can also be Conduct the test in another test chamber (space). 5.2.3 According to the provisions of Figure 2, the temperature in the working space is cyclically changed within 24 hours: a. Heating stage. Within 3 ± 0.5 hours, the temperature of the working space is continuously increased to the high temperature specified in the relevant standards, and the heating rate should be limited to the shaded range of Figure 2. In this stage, except for the last 15 minutes when the relative humidity may not be lower than 90%, the relative humidity at other times shall not be lower than 95% in order to produce condensation on the test samples. However, large test samples shall not produce excessive condensation. Note: The generation of condensation on the test sample means that the surface temperature of the test sample is lower than the dew point temperature of the air in the working room. b. High temperature and high humidity constant stage. Maintain the temperature of the working space within the range of 40 ± 2°C (or 55 ± 2°C) until 120.5 h.
In this stage, except for the first and last 15min, the relative humidity should not be less than 90%, and the rest of the time should be 93±3% c. Cooling stage. The temperature of the working space is reduced from 40±2℃ (or 55±2℃) to 25±3℃ within 3 to 6h. The cooling rate should be limited to the shaded range specified in Figure 2. It should be noted that the cooling rate within 1.5h after the start of cooling is the cooling rate from 40±2℃ or 55±2℃ to 25±3℃ within 3h+15min. In this stage, the relative humidity has two changes:
Change 1: Except for the first 15min, the relative humidity should not be less than 90%, and the rest of the time should not be less than 95%. Change 2: The relative humidity is allowed to be not less than 85%2. d, low temperature and high humidity constant stage. The temperature of the working space is maintained at 25±3C, and the relative humidity should not be less than 95% until 24h from the start of the heating stage.
5.3 Intermediate testing
5.3.1 During the conditional test, the relevant standards may require the electrical and (or) mechanical properties of the test samples to be tested. 5.3.2 During the intermediate testing, it is not allowed to remove the test samples from the working space and then perform the measurements after recovery. 5.3.3 If intermediate testing is required, the relevant standards should clearly specify the measurement items and the stage (s) of the conditional test at which the measurements are to be performed. 5.4 Recovery
5.4.1 After the conditional test, the test samples should be restored for 1 to 2 hours. The relevant standards should specify whether the recovery is carried out under the standard atmospheric conditions of the test in Article 5.3 of GB2421 or under the controlled recovery conditions in Article 5.4.1. 5.4.2 If recovery is required under controlled recovery conditions (Figure 3), the test sample can be moved to another test box (room) for testing. The time for transferring the sample should be as short as possible. If there is no regulation in the relevant standards, it should generally not exceed 10tnin; the test sample can also be left in the original test equipment for use. Note:
The limitation on the condensation of large test samples is added by this standard. 2] [EC68-8-30 (1980) stipulates that the relative humidity should not be less than 80%. GB/T 2423.4-93
For recovery, at this time, the relative humidity in the working space of the test box (room) should be reduced to 75% ± 3% within 0.5h, and then the temperature should be reduced to the laboratory temperature within 0.5h, with a tolerance of 2℃11. Note: The laboratory temperature should be within the range specified in Article 5.3 of GB 2121 at this time. 5.4.3 The recovery time should be calculated from the time when the specified recovery conditions are reached. 5.4.4 For test samples with large thermal time constants, the recovery time should be long enough to allow the test samples to reach temperature stability. 5.4.5 The relevant standards should specify whether special measures should be taken to remove moisture from the surface of the test samples. 5.5 Final test
5.5.1 Inspect the appearance of the test samples in accordance with the provisions of the relevant standards; test their electrical and mechanical properties. 5.5.2 The final test should be carried out immediately after the recovery phase, and the parameters most sensitive to relative humidity should be measured first. If there are no other provisions, the measurement of all parameters should be completed within 30 inches. Details to be specified when citing this standard
When the relevant standards adopt this test method, the following items shall be specified: Severity level
Initial test
State of the test sample during the conditioning test Requirements for the sample rack or support
Lower limit of relative humidity during the cooling stage
Intermediate test
Restoration conditions
Measures to eliminate surface moisture
Final test
Adoption period:
See Chapter 4
See 5.1
See 5.2.1
See 5.2.1
See 5.2.3c
See 5.3
See 5.4.1
See 5.4.5tea
See 5.5
1) [EC 68-2-30 (1980) stipulates that the relative measurement is 75 ± 2% and the temperature tolerance is ± 1 ° C. (%)
(:2.) Period requirements
GB/T 2423.4-93
Regular
+28℃
+22 ℃
Time required to reach the test sample temperature
First cycle
+Relative humidity reaches 95%~100%
Time required does not exceed 1h
—Start of first cycle
Figure 1 Test Db: Stabilization stage
·Time
Instructions for use:
41 or +5
GB/T2423.4—93
Opening and gathering
Start of dehumidification
15min iamin g0% 15mialil15min--285%
0 or 55）-20
-12 ±0.5h
Figure 2 Test Db: Test cycle\
1] Figure 2 is a combination of Figures 2a and 26 of [IEC68-2-30 (1980). %
+28℃
Adoption instructions:
GB/T2423.4-93
, final cycle step
final cycle end
..0.5h
Recovery bundle
One time
Experimental weight humidity (15 ~ 35℃)12
Figure 3 Test Db: Recovery under controlled recovery conditions 1) IEC 68-2-30 (1980) stipulates ±1C. Addition
GB/T 2423.4-93
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. TF
This standard was drafted by the National Technical Committee for Environmental Conditions and Environmental Tests for Electrical and Electronic Products and funded by the Guangzhou Electric Science Research Institute of the Ministry of Machinery Industry. The drafters of this standard are Xie Hua, Xu Yuxiamei and Zhong Kaihua.
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