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GB/T 2424 comprises the following three parts:
——GB/T 2424.1-2005 Environmental testing for electric and electronic products-Guidance for high temperature and low temperature tests (IEC 60068-3-1: 1978, IDT)
——GB/T 2424.2-2005 Environment tests for electric and electronic products - Guidance for damp heat tests (IEC 60068-3-4: 2001, IDT)
——GB/T 2424.5-2006 Environmental tests for electric and electronic products - Confirmation of the performance of temperature chambers (IEC 60068-3-5: 2001, IDT)
——GB/T 2424.6-2006 Environmental testing for electric and electronic products - Confirmation of the performance of temperature/humidity chambers (IEC 60068-3-6: 2001, IDT)
——GB/T 2424.7-2006 Environmental tests for electric and electronic products - Measurements in temperature chambers for tests A and tests B (with load) (IEC 60068-3-7: 2001, IDT)
——GB/T 2424.10-1993 Basic environmental testing procedures for electric and electronic products - General guidance of accelerated testing for atmospheric corrosion (eqv IEC 60355: 1971)
——GB/T 2424.11-1982 Basic environmental testing procedures for electric and electronic products; Guidance for sulphur dioxide test for contacts and connections
——GB/T 2424.12-1982 Basic environmental testing procedures for electric and electronic products; Guidance for hydrogen sulphide test for contacts and connections
——GB/T 2424.13-2002 Environmental testing for electric and electronic and electronic products - Part 2: Test methods - Guidance on change of temperature tests (IEC 60068-2-33: 1971, IDT)
——GB/T 2424.14-1995 Environmental testing for electric and electronic products - Part 2: Test methods - Guidance for solar radiation testing (idt IEC 60068-2-9: 1975)
——GB/T 2424.15-1992 Basic environmental testing procedures for electric and electronic products - Guide for combined temperature/low air pressure tests (eqv IEC 60068-3-2: 1976)
——GB/T 2424.17-1995 Environmental testing for electric and electronic products - Guidance on soldering test
——GB/T 2424.19-2005 Environment tests for electric and electronic products - Guidance on the application of the environmental test to simulate the effects of storage (IEC 60068-2-48: 1982, IDT)
——GB/T 2424.20-1985 Basic environmental testing procedures for electric and electronic products - Guidance for test simulating inclinations and motions
——GB/T 2424.21-1985 Basic environmental testing procedures for electric and electronic products - Guidance on solderability testing by the wetting balance method
——GB/T 2424.22-1986 Basic environmental testing procedures for electric and electronic products; Guidance for combined temperature (cold and heat) vibration (sinusoidal) tests (eqv IEC 60068-2-53: 1984)
——GB/T 2424.23-1990 Basic environmental test procedures for electric and electronic products - Guidance for water test
——GB/T 2424.24-1995 Basic environmental testing procedures for electric and electronic products - Guidance for combined temperature (cold and heat)/low air pressure/vibration (sinusoidal) test
——GB/T 2424.25-2000 Environmental testing for electric and electronic products Part 3: Test guidance Seismic test methods (idt IEC 60068-3-3: 1991)
This is Part 5 of GB/T 2424, which is equivalent to IEC 60068-3-5: 2001 Environmental testing - Part 3-5: Supporting documentation and guidance - Confirmation of the performance of temperature chambers (English Version).
Considering the actual conditions in China, the following editorial changes present in this part, in the adoption of IEC 60068-3-5:
——Chinese standards adopting international standards are referred and their orders are changed;
——Foreword and Introduction of IEC 60068-3-5 are deleted;
——national standards are added in this Foreword;
——editorial changes for the figure and table in IEC 60068-3-5 are made:
This standard was proposed by China Electrical Equipment Industrial Association.
This standard is developed by Guangzhou Electric Apparatus Research Institute.
This part is under the jurisdiction of the National Technical Committee on Electric and Electronic Product Environment Technology of Standardization Administration of China (SAC/TC 8).
This part is issued for the first time.
Environmental tests for electric and electronic products - Confirmation of the performance of temperature chambers
1 Scope
This part of GB/T 2424 provides a uniform and reproducible method of confirming that temperature test chambers, without load, conform to the requirements specified in GB/T 2423 and other standards. This standard is intended for users when conducting regular test chamber performance monitoring.
2 Normative references
The following documents contain provisions which, through reference in this part of GB/T 2424, constitute provisions of this part. For dated references, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply to this part.
GB/T 2421 Environmental testing for electric and electronic products - Part 1: General and guidance (GB/T 2421-1999, IEC 60068-1: 1988, IDT)
GB/T 2423 (relevant parts) Environmental testing for electric and electronic products - Part 2: Test methods
GB/T 2424.6 Environmental testing for electric and electronic products - Confirmation of the performance of temperature/humidity chambers (GB/T 2424.6-2006, IEC 60068-3-6: 2001, IDT)
GB/T 2424.7 Environmental tests for electric and electronic products - Measurements in temperature chambers for tests A and tests B (with load) (GB/T 2424.7-2006, IEC 60068-3-7: 2001, IDT)
GB/T 16839.1 Thermocouples - Part 1: Reference tables (GB/T 16839.1-1997, IEC 60584-1: 1995, IDT)
GB/T 19022 Measurement management systems - Requirements for measurement processes and measuring equipment (GB/T 19022-2003, ISO 10012: 2003, IDT)
IEC 60751 Industrial platinum resistance thermometers and platinum temperature sensors
3 Terms and definitions
For the purposes of this part, the following terms and definitions apply.
3.1
temperature test chamber
enclosure or space in some parts of which the temperature conditions, specified in GB/T 2423, can be achieved
3.2
temperature setpoint
desired temperature as set by the test chamber control system
3.3
achieved temperature
temperature in the test chamber at any point within the working space after stabilization
3.4
temperature stabilization
temperature at which all points in the working space have reached and maintained the setpoint temperature within a given tolerance
3.5
temperature fluctuation
difference, after stabilization, between the maximum and minimum temperatures at any point in the working space during a specified interval of time
3.6
working space
part of the test chamber in which the specified conditions can be maintained within the specified tolerances
Figure 1 Working space
Table 1 Practical dimensions
Specification Volume/L Distance/mm Xmin/mm
Small <1000 L/10 50
Medium 1000~2000 L/10 100
Large >2000 L/10 150
Note: not all test chambers are cubic in construction.
3.7
temperature gradient
maximum difference in mean value, after stabilization, at any moment in time between two separate points in the working space
3.8
temperature rate of change
rate, in degrees per minute, for the transition between two specified temperatures measured at the center of the working space
3.9
temperature variation in space
difference in mean value, after stabilization, at any moment in time between the temperature at the center of the working space and at any other point in the working space
3.10
temperature extremes
maximum and minimum measured temperatures achieved in the working space after stabilization
Figure 2 Example of temperature differences
4 Measuring test chamber performances
4.1 Test area environment
The environment around a temperature test chamber may influence the conditions inside the test chamber.
The confirmation of performance of temperature test chambers shall be carried out under standard atmospheric conditions.
The following items shall be taken into consideration:
——the ambient conditions described in GB/T 2421 shall be satisfied in principle;
——the test chamber shall not be exposed to direct solar radiation;
——the test chamber shall not be exposed to electromagnetic interference;
——the test chamber shall be leveled;
——the test chamber shall be fixed in a location free from any mechanical and acoustic vibration interference.
Manufacturer's advice on electrical power requirements and the environmental conditions shall be taken into consideration.
Abnormal conditions shall be recorded.
4.2 Temperature measurement system
The uncertainty of measurement of the output of the measurement system shall be determined by calibration of the system, traceable to GB/T 19022.
Normally sensors shall be either the resistance type (in accordance with IEC 60751) or the thermocouple type (in accordance with GB/T 16839.1). The 50% response time in air of the sensor shall be between 10s and 40s. The response time of the overall system shall be less than 40s.
In a temperature range from -200℃ to +200℃, the sensor measurement uncertainty shall be in accordance with class A of IEC 60751.
4.3 Temperature test chamber test load
All measurements described below are performed with an empty working space. If it is not possible to empty the test chamber totally, this shall be recorded. For measuring with test load (with or without heat dissipation), see IEC 60751.
4.4 Installation of temperature sensors
Temperature measuring sensors are located in each corner of the test chamber and in the center of the working space (see Figure 3, minimum 9 sensors). For temperature test chambers over 2000L, additional sensors shall be located in front of the center of each wall (see Figure 4, minimum 15 sensors). The measurement system shall be arranged in such a way that the temperature distribution of the empty test chamber will not be affected. Recording of the achieved temperature shall be effected.
For confirmation monitoring, data shall be recorded at least once a minute. The device used for recording data from the test chamber monitoring sensors shall be independent of the test chamber control system.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Measuring test chamber performances
5 Standard temperature test sequence
6 Evaluation criteria
7 Information to be given in the performance test report
