AS NZS IEC 60947.5.4:2015 pdf free
AS NZS IEC 60947.5.4:2015 pdf free.Low-voltage switchgear and controlgear
A method of assessing the performances of low-energy contacts by special tests is proposed.As the failures of such contacts are of a random nature, the method is based on a continuous monitoring of the contacts under test.
For the basic method (see 6.1.1)， the voltage drop between the terminals of the closed contact (steady state – see 3.1.9) is measured for each operation and compared to a specified threshold.
In the alternative method, the behaviour of the load is monitored at each operating cycle.The measurement is performed under constant voltage U (see figures 2 and 3). The contact(s) under test is (are) mounted and connected as in normal service and under ambient conditions as defined in clause 8. The measurement of the voltage drop is made directly on the connecting terminals of the contact(s) or on the connecting terminals of the load (see 6.1.2).
In the basic and alternative methods recommended here (see 6.1.1 and 6.1.2), the contacts under test switch (make and break) the load.
For tests without switching the load, the analysis may be performed on the same equipment.
The testing equipment for this purpose should, therefore, be designed accordingly.
It may be possible to test the contact(s) in particular environments (dry heat, dust, damp heat,H2S, etc.). Such environments shall be agreed between the user and the manufacturer, and shall be chosen from those defined in the IEC 60068-2 series (see clause 8).
The number of operating cycles of the test shall be at least 25 %，and not more than 100 %, of the durability with the number of operating cycles at low energy stated by the manufacturer.
Unless otherwise stated, this stated number is the mechanical durability.
For these recommended tests (basic method or alternative method), the contact under test switches the load and AX (see figures 2 and 3) is permanently closed during the test. The sequential diagram is given in figure 4.
For specific applications, the contact under test does not switch the load. An example of a sequential diagram is given in figure 5.
In these diagrams, the represented functions (C, 1, etc.) are those indicated in figures 2 and 3.The function M is actually the measurement of the contact voltage drop for the basic method.It can also be the monitoring or the recording of the state of the load in the alternative method.AS NZS IEC 60947.5.4 pdf free download.
