AS NZS IEC 60947.5.2:2015 pdf free download – Low-voltage switchgear and controlgear
8.3.3.2.4 Independent (snap) action
Independent (snap) action shall be checked at maximum and minimum operating load currents at both maximum and minimum rated operating voltages. Resistive loads of appropriate value shall be used for each of the four tests. These tests shall be carried out by moving the target from a position where the switching element is in the OFF-state to a position where the switching element is in the ON-state and observing the output on an oscilloscope. The switching element function shall be substantially independent from the velocity of the target and the output shall switch between the ON and the OFF states without oscillating, or holding at any intermediate level.
8.3.3.3 Temperature rise
The proximity switch, installed in free air, is supplied with its rated operational voltage (U e ) (or the highest operational voltage of its voltage range), and connected to a load corresponding to its rated operational current (I e ) until the thermal equilibrium is reached. The temperature rise, measured on the terminals when applicable, and on any point of the enclosure shall not exceed 50 K (see 7.2.2).
The target is placed in a position such that the switching element is in the ON-state, R 1 is selected so that the current flowing through the proximity switch is equal to its rated operational current. The supply S shall be adjusted to 1 00 A prospective short-circuit current. The “SC” switch, parallel with R 1 load, is intended to cause the short circuit. The open circuit voltage shall be 1 ,1 times the rated operational voltage or the maximum value of the voltage range. The test shall be performed three times by randomly closing the “SC” switch. The test current is maintained until the SCPD or the internal short-circuit protection in the proximity switch has operated. The interval between each of the three tests shall be not less than 3 min. The actual time between tests shall be stated in the test report. After each test, the “SCPD” shall be replaced or reset.
8.4.1.1 Test conditions
A proximity switch in new condition is mounted according to the relevant annex and the target is moved, not faster than 1 mm/s, towards and away from the sensing face of the proximity switch in an axial direction. The operating distances are measured as shown in Figures 3 and 4.
8.4.1 .2 Effective operating distance (s r )
The effective operating distance is measured at the rated voltage or at any voltage within the voltage range and at 23 °C ± 5 °C ambient air temperature. The measured value shall be within the limits given in 7.2.1 .3.1 .
8.4.1.3 Differential travel (H)
The differential travel is defined as a percentage of the effective operating distance (s r ). The measurement is made at the ambient temperature of 23 °C ± 5 °C at rated supply voltage. The target shall be moved towards the proximity switch within the (s r ) range and then be moved away from the proximity switch. The measured value shall be according to 7.2.1 .5.