IEC 60947-7-4:2013 pdf free download

IEC 60947-7-4:2013 pdf free download
IEC 60947-7-4:2013 pdf free download.Low-voltage switchgear and controlgear
8.4.5 Temperature rise test
This test serves to evaluate the ability of the PCB terminal block to carry the rated current permanently without exceeding the upper limiting temperature (ULT). Unless otherwise specified, the test shall be carried out according to IEC 60512-5-2 under the following test conditions.
The test is carried out on an assembly of PCB terminal blocks mounted next to each other with preferably four contact units per level as shown in Figure 1 and Figure 2. The PCB terminal block shall be mounted on a printed circuit board as in normal use and connected in series with insulated conductors of the maximum cross-section and conductors on the printed circuit board. The interconnections on the printed circuit board shall be made with solid bare conductors of equal cross-section or comparable means and as short as possible.
The test assembly shall be prepared and arranged for the test procedure as shown in Figure 1 according to the test conditions described in IEC 60512-5-2，Test 5b. Unless otherwise specified, the size of the printed circuit board shall be selected so that it protrudes over the base area of the PCB terminal block on all sides corresponding to five times the spacing of the PCB terminal block. The printed circuit board that is used shall be described in the test report.
After verification of the contact resistance as described in 8.4.4, the test shall be carried out with single-phase alternating or direct current as described in IEC 60512-5-2, Test 5b.
As described in IEC 60512-5-2, the measuring points for measuring the temperature shall be located on the hottest spot above the printed circuit board (component side).
Where applicable it may be necessary to determine the hottest spot by carrying out pre-tests.
The reduction factor to determine the derating curve is 0,8. If this is not adhered to, the derating factor used shall be indicated in the technical documentation.
At the end of the test and after cooling down to ambient temperature the PCB terminal block shall comply with the contact resistance test according to 8.4 .4 without modification of the assembly.