The test methods specified in this standard shall be adopted when the detailed specifications of electromechanical components for electronic equipment within the scope of TC48 are required. They may also be adopted when the detailed specifications of similar components are required. GB/T 5095.3-1997 Basic test procedures and measurement methods for electromechanical components for electronic equipment Part 3: Current carrying capacity test GB/T5095.3-1997 Standard download decompression password: www.bzxz.net

GB/T5095.3-1997
This standard is equivalent to IEC512-3:1976 "Current Capacity Test for Electromechanical Components for Electronic Equipment", which is the first revision of GB5095.3-86. This standard is proposed by the Ministry of Electronics Industry of the People's Republic of China. Basic test procedures and measurement methods Part 3: This standard is under the jurisdiction of the National Technical Committee for Standardization of Electromechanical Components for Electronic Equipment. This standard was drafted by the Standardization Institute of the Ministry of Electronics Industry. The main drafters of this standard are Yu Yufang, Wang Qilong, Zhang Juhua, and Gong Yutang. GB/T5095.3-1997
IEC Foreword
1) Formal resolutions or agreements of IEC (International Electrotechnical Commission) on technical issues are formulated by technical committees participated by national committees with special concerns about these issues, and represent the international consensus on the issues involved as much as possible. 2) These resolutions or agreements are published in the form of standards, technical reports or guidelines, and are used internationally in the form of recommendations, and in this sense, they are recognized by various national committees.
3) In order to promote international unification, each IEC National Committee has the responsibility to make its national and regional standards adopt IEC standards as much as possible. 1 Any differences between IEC standards and corresponding national or regional standards should be indicated in the national or regional standards. IEC Introduction
International standard IEC512-3 was developed by IEC/TC48 (Electromechanical components for electronic equipment). This standard is part 3 of the entire set of standards.
This standard is used together with Part 1: General (IEC512-1: 1984). The other test items included in the entire set of standards are given in Appendix A of IEC512-1. These test items are published after they are developed.
This standard is scheduled to replace IEC130-1 "Test items for connectors with frequencies below 3MHz". The proposal for the corresponding test 5a in Part 1: General requirements and test methods was discussed at a meeting held in London in September 1973 and formed into document 48 (CO) 120, which was sent to the national committees for voting according to the "six-month method" in July 1974. The countries that agreed to publish test 5a are as follows: Argentina
Hungary
Spain
Belgium
Israel
Yugoslavia
Canada
Italy
Turkey
Portugal
Romania
The proposal for test 5b was discussed at a meeting held in London in September 1973 and formed into document 48 (CO) 130, which was sent to the national committees for voting according to the "six-month method" in August 1974. Then, it was sent to the national committees for voting according to the "two-month procedure" in October 1975 as document 48 (CO) 193.
The countries that agree to issue test 5b are as follows: Austria
Romania
Belgium
Spain
Hungary
Yugoslavia
Canada
Israel
Italy
Portugal
Turkey
National Standard of the People's Republic of China
Electromechanical components for electronic equipmentBasic testing procedures and measuring methodsPart 3:Current-carrying capacity testsGB/T5095.3-1997
idt IEC 512-3:1976
Replaces GB5095.3-86
The test methods specified in this standard shall be adopted when required by detailed specifications for electromechanical components for electronic equipment within the scope of TC48*. They may also be adopted when required by detailed specifications for similar components. 1 Test 5a: Temperature rise
1.1 Purpose
To establish detailed standard test methods to assess the ability of components to continuously transmit specified currents without exceeding specified temperature rises. 1.2 Preparation of test samples
The test samples shall be equipped with temperature sensing devices, connected with wires of the specified wire size with a minimum length of 50 mm, and the test samples shall be installed as specified in the detailed specifications.
Note: Care must be taken to prevent the test samples from being cooled by air currents or other artificial factors. 1.3 Test method
The specified test current shall be applied to each contact of the test sample for 5 h. The ambient temperature shall be recorded before and after the test.
1.4 Requirements
Each contact of the test sample must be able to pass the specified current for 5 hours without exceeding the specified temperature rise. 1.5 Details to be specified
Detailed specification requirements The following details should be specified for this test: a) Sensitivity and placement of the temperature sensor; b) Wire number;
c) Wiring method and lead-out terminal type of the test sample: d) Installation method of the test sample;
*Scope of TC48: To formulate international standards for related components with electromechanical connection and switching functions for communication equipment and electronic devices using similar technologies.
1R.F. connectors should not belong to this technical committee and should be formulated by TC46 together with RF cables. 2 Sockets for components such as crystals or electron tubes shall be considered by relevant technical committees. Approved by the State Administration of Technical Supervision on December 26, 1997 and implemented on October 1, 1998
e) AC current or DC current.
GB/T5095.3-1997
f) Temperature rise value, the preferred value is 20K, 30K and 40K; g) Ambient temperature;
h) What is the difference with the standard test method. 2 Test 5b: Current and temperature derating curve 2.1 Purpose
To establish a detailed standard test method to evaluate the current carrying capacity of electromechanical components. 2.2 General provisions
2.2.1 Determine the current carrying capacity curve
The current carrying capacity is limited by the thermal properties of the materials used for the contacts and terminal parts and the thermal properties of the insulating materials. Therefore, the current carrying capacity is a function of the heat generated by the component itself during operation and the ambient temperature in the environment in which it is located. Using the measurement method specified in 2.4, measure the temperature of the component point (approximately the hottest point) and the ambient temperature tu near the component at different currents. The difference between the two temperatures is the heat generated by the current itself or called temperature rise. This can be expressed as follows: ttu = At
The relationship between the current, temperature rise and ambient temperature of the component is shown by the curve in Figure 1. Unless otherwise specified, this temperature rise value should be obtained based on the average current of the three test samples. The average value is calculated from the values ​​measured by the three test samples and used to draw the basic curve. At least three points are required to establish the basic curve.
Upper limit determined by external factors
(such as the cross-sectional area of ​​the connecting wire)
Current range
Allowed working area
Example of current carrying capacity curve
Basic curve
Correction curve
Figure 2 Example of derating curve
Upper limit temperature of material
Ambient temperature
Upper limit temperature of material
As shown in Figures 1 and 2, with current 1 as the ordinate and temperature t as the abscissa, a vertical line is drawn in the figure to mark the upper limit temperature allowed by the material used. The temperature rise △At (the average value of three test samples) measured at current I. can be deduced from the figure, and the maximum ambient temperature tu allowed at current I. can be obtained. Because the sum of the ambient temperature and the temperature rise △t cannot exceed the upper temperature limit of the material. 30
2.2.2 Derating curve
GB/T5095.3—1997
A derating curve should be specified in the relevant detailed specifications, which is derived from the basic curve formulated in accordance with 2.2.1 (see Figure 2). The curve should take into account both the differences in the test samples and the errors of the measuring equipment in temperature measurement. The derating factor is introduced because the current carrying capacity can be further limited by some external factors, such as the wire specifications and the uneven distribution of the load line. If the result of these factors makes the current carrying capacity different from the expected value due to heating limitations, a correction value should be introduced. Note: In practice, it is often not the maximum current that can be allowed for all terminal parts to carry at the same time. Because, in many cases, as long as the number of terminal pieces used is less than 20% of the total number, a single terminal piece can pass several times the derated current determined by the derating curve. For these cases, general principles cannot be formulated, and the current carrying limit must be determined based on individual circumstances. In these cases, it is recommended to flexibly use the method established in this standard. 2.2.3 Use of the ampacity curvebZxz.net
The standard ampacity curve specified in this standard is represented by the derating curve determined in 2.2.2. It is indeed a derating curve, since it gives the maximum permissible current as a function of the ambient temperature. The shaded area in Figure 2 represents the permissible operating area. NOTE If the detail specification specifies ampacity data, then reference should be made to the ampacity curve already specified in this standard. If tabulated values ​​are preferred, they should be consistent with the ampacity curve. 2.3 Test details
2.3.1 Measuring equipment
The measurements should be made in still air as far as possible. Therefore, the test specimen is installed in a closed box to prevent the surrounding environment from being affected by external air flow. The closed box should be made of non-reflective material. The side walls of the closed box are movable to accommodate different test specimen sizes. The side walls of the closed box should be no less than 20 cm from the edge of the test specimen. The closed box does not need to have a top cover.
The test samples are arranged on a horizontal plane 5 cm from the bottom of the box, at least 15 cm from the top, and the distance to each side wall should be equal. The test samples are suspended freely as much as possible. If this is not possible, use an insulating material with a thermal conductivity of not more than 2 W/m·K as a cushion, but the area of ​​contact between the test sample and the insulating material should not exceed 20% of the surface area of ​​the test sample. The test sample should be connected to a wire of appropriate cross-section according to the required maximum current or lead size. In order to reduce the heat dissipation to the outside and reach the minimum limit, the length of the wire in the measurement box should be at least 25 cm. For the test of multiple test samples, all contacts should be connected in series with wires of the same specification as the connecting wire, and the length of each connecting wire should be 25 cm. Note
1 For test samples with detachable contacts, care should be taken not to disturb the contacts with the connecting wire. 2 A plugged connector is used as a test sample. 3 When the test sample is a free-end connector with a cable, the length of the cable in the measurement box should be at least 25 cm. The contacts are connected in series by means of a bonding cable at a distance of 25 cm from the test specimen.
2.3.2 Details of temperature measurement
The temperature is measured by two temperature sensors, the leads of which pass through the insulating wall of the measuring device. The measuring point for measuring the ambient temperature is located in a horizontal plane passing through the axis of the test specimen, 5 cm from the midpoint of the edge of the longest side of the test specimen.
The measuring point for measuring the temperature of the test specimen shall be specified in the detailed specification. NOTE The temperature sensors may be thin thermocouples, such as nichrome or nickel wires, with a diameter of less than 0.3 mm. If the calibration curves of the two thermocouples used are the same, they may be connected in reverse in the measuring circuit, so that the temperature rise △t is measured directly (see Figure 3). However, the temperature t of the test specimen must be monitored in any case and must not be allowed to exceed the upper temperature limit of the material. Measuring closed box
Constant current source
Test sample
Figure 3 Wiring method of measuring instrument
2.4 Measuring method
GB/T5095.3—1997
The arrangement of the test sample in the measuring box shall be as specified in 2.3.1, and its terminal shall be connected to the regulated power supply through an ammeter. The load current may be DC or AC. When AC is used, it shall be an effective value, and the time maintained at each selected current level shall not exceed 1 h, or until thermal equilibrium is reached. 2.5 Details to be specified
Detailed specification requirements The following details shall be specified for this test: a) Preparation of test samples;
b) Type and specification of cable or wire bundle used; c) Measurement point of test sample temperature;
d) Upper limit of temperature;
e) Number of test samples (if not 3); f) Differences from the standard test method. 32
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