AS NZS IEC 60947.4.3:2015 pdf free
AS NZS IEC 60947.4.3:2015 pdf free.Low-voltage switchgear and controlgear
When either one or both switching devices are identified as dependent components, the switching devices shall comply with the following:
a) the switching devices shall be combined, rated and tested as a unit;
b) the switching devices shall be interlocked, by any of the following means, either individually or in combination: electrical, electronic or mechanical means, such that the mechanical switching contacts shall not be required to make or break overload currents without direct intervention by the semiconductor switching device;
c) the semiconductor switching device shall be enabled to take over the control of the current flowing in the main circuit whenever it is necessary to make or break overload currents.The requirements of 7.2.2 of IEC 60947-1:2007 apply to controllers and contactors in a clean, new condition.
NOTE Contact resistance due to oxidation can impact the temperature rise test at test voltages below 100 V. In the case of conducting the test at a voltage below 1 00 V, mechanical switching devices can have the contacts cleaned either by any non-abrasive method or by carrying out operating cycles with or without load several times prior to initiating the test at any voltage.
Temperature rise deviations on the metallic radiator surface of semiconductor devices are permitted: 50 K in the case where they need not be touched during normal operation.If the limit of 50 K is exceeded, the manufacturer shall provide a suitable warning (e.g. symbol IEC 60417-5041 (2002-10))1) in accordance with 6.3. Provision of suitable guarding and location to prevent danger is the responsibility of the installer.
For devices identified as dependent components (see 8.2.1.7), the temperature rise shall be verified by the procedures given in 9.3.3.3.4 and 9.3.3.6.2 (including Table 7 and Table 13). The device shall be tested as an integral part of a unit where the prescribed on-load periods for the two switching devices (Table 7) shall be determined by a sequence of operations which is the same as intended in normal service.AS NZS IEC 60947.4.3 pdf free download.
