AS NZS IEC 60947.4.2:2015 pdf free
AS NZS IEC 60947.4.2:2015 pdf free.Low-voltage switchgear and controlgear
The first digit of the utlization category identification designates a semiconductor switching device (for example within this standard a semiconductor motor controller or starter). The second digit designates a typical application. The a-suffix designates the capability of a controller to perform any of the functional possibilities listed in Table 1. The b-suffix designates the capability of a controller where it is restricted to performing a transition from an OFF-state to a starting function of duration Tx, and immediately returning to the OFF-state to comprise a duty cycle in accordance with the requirements of 8.2.4.1.
Assignment of ratings based on the results of tests A designated controller or starter with a rating for one utilization category which has been verified by testing can be assigned other ratings without testing, provided that
– the rated operational current and voltage that are verified by testing shall not be less than the ratings that are to be assigned without testing;
– the utilization category and duty cycle requirements for the tested rating shall be equal to or more severe than the rating that is to be assigned without testing; the relative levels of severity are given in Table 3;
– the overload current profile for the tested rating shall be equal to or more severe than the rating that is to be assigned without testing, in accordance with the relative levels of severity in Table 3. Only values of X lower than the tested value of X may be assigned without testing.
However, if the current setting is influenced by the conditions of use or other factors which cannot readily be marked on the relay, then the relay or any interchangeable parts thereof (for example heaters,operating coils or current transformers) shall carry a number or an identifying mark which makes it possible to obtain the relevant information from the manufacturer or his catalogue or, preferably, from data furnished with the starter.
In the case of current transformer operated overload relays, the marking may refer either to the primary current of the current transformer through which they are supplied or to the current setting of the overload relays. In either case, the ratio of the current transformer shall be stated.AS NZS IEC 60947.4.2 pdf free.
