SU953599A1 - Method of evaluating quality of non-detachable aluminium contact joints - Google Patents

Description

one

The invention relates to electrical measuring equipment and can be used to assess the quality of permanent aluminum contact joints.

A known method for assessing the quality of contact joints, for example, accelerated testing in the cyclical heating mode, GOST, consists in heating the contact joints to 120 ± 1CPc, followed by cooling to ambient temperature, not more than 30 ° C. The magnitude of the test current is established empirically at the rate of the min of heating. The number of cycles of heating and cooling should be at least 200 lJ ..

 However, this method requires considerable effort in assessing the quality of contact connections, without revealing the entire process of changing the parameters to be determined (temperature, resistance).

The closest to the proposed technical essence is a method for assessing the quality of permanent agvominium contact joints, namely, that the heating is carried out up to 200-250С by the influence of a current that exceeds the current for the tested contact joint by 12-13 times for 2-5 minutes, and

, Q, the number of cycles is chosen equal to 20. Registration of the parameters studied is carried out directly in the process of testing t2J.

A disadvantage of the known method 15 is the low accuracy of the evaluation of the quality of the connections, due to the presence of uncontrolled physical processes when tested with a current much higher than the nominal, from personal processes that are observed at the rated current (formation of micro-welding of the contacting areas, etc.).

The purpose of the invention is to improve the accuracy of the assessment while reducing the time of testing.

This goal is achieved by the fact that according to the method of assessing the quality of one-piece aluminum contact joints, including cyclical heating to a certain temperature by passing a current through the test contact joint and cooling to ambient temperature, the parameters being studied are heated to 200-250 ° C for 2- 5 minutes a constant and nominal current for the contact connection is passed through the test contact connection. The drawing shows a block diagram of an apparatus for carrying out the proposed method. The device includes a low-voltage converter unit ANG 5000/2500 1j registration unit 2, cyclic heating unit 3, current adjustment unit 4, power supply unit 5, current control unit 6, test chamber 7 consisting of two parts, one of which has fixture 8 to install the sample 9 and the power clamp 10, and the second part is removable (when installing or cooling the contact connection, it folds back), shunt 11, fan 1 for cooling the test sample, ceramic sleeves 13, heating elements H, sensors 15 and a thermocouple sixteen. . The test specimen 9 is a contact connection of aluminum conductors made by cold pressing or hot welding. After installing the test specimen on the fixture 8 and fixing the power clamp 10 on it, the thermocouple 16 is coded into the contact joint to control the heating temperature and two sensors 15 register the monitored parameter, while the thermocouple 16 connects to the cyclic heating unit 3, and the sensors connect to unit 2 registration. The thermocouple and sensors are connected to the above instruments through ceramic sleeves J3. In the process of testing sample 9, a rated current corresponding to the conductor cross section is supplied to it from the low-voltage converter unit 1. The magnitude of the current during the test remains unchanged.

The control of the operating current is carried out by the block 6 through the shunt P, and its adjustment - by the block 4.

Claims (1)

Testing of the contact connection is carried out in chamber 7, where heating elements 1 are not installed on the heat insulating layer (not shown) The power of the heating elements is selected so that the test sample heats up to 200-250 C for a minute. The temperature control of the contact connection is monitored unit 3 through thermocouple 16. Upon reaching the set temperature, unit 3 is cycled heating and turns off the heating elements, and also simultaneously turns on the fan 12 for forced cooling The sample alternates with cooling. The number of heating-cooling cycles should be no more than 20. Once the test sample has reached a temperature of 30tlc from the cyclic heating unit 3, it is fed into the registration unit 2, where For example, a digital millivoltmeter and a digital printing device records the electrical resistance of the contact connection. The obtained test results are processed using known methods of mathematical statistics. The proposed method eliminates the formation of micro-welding of the contacting sites, which occurs when currents close to the short-circuit currents pass through them, approximates the physical aging process of the contact connections when testing in the forced mode to the aging process of the contact connections in the nominal current mode, allows to determine the service life contact connections at rated current, i.e. in operation mode. The invention The method of assessing the quality of one-piece aluminum contact compounds, including cyclic heating to a certain temperature by skipping