Appareillage à basse tension - Partie 4-2 : Contacteurs et démarreurs de moteurs - Gradateurs et démarreurs à semiconducteurs de moteurs à courant alternatif

1.1 Scope

This part of IEC 60947 applies to the types of equipment listed in 1.1.1 and 1.1.2 whose main contacts are intended to be connected to circuits the rated voltage of which does not exceed 1 000 V a.c. or 1 500 V d.c.

Starters and/or contactors dealt with in this standard are not normally designed to interrupt short-circuit currents. Therefore, suitable short-circuit protection (see 9.3.4) forms part of the installation but not necessarily of the contactor or the starter.

In this context, this standard gives requirements for:

– contactors associated with overload and/or short-circuit protective devices; – starters associated with separate short-circuit protective devices and/or with separate shortcircuit and integrated overload protective devices; – contactors or starters combined, under specified conditions, with their own short-circuit protective devices. Such combinations, e.g. combination starters or protected starters are rated as units.

For circuit-breakers and fuse-combination units used as short-circuit protective devices in combination starters and in protected starters, the requirements of IEC 60947-2 and IEC 60947-3 respectively apply.

Equipment covered by this standard is as follows.

1.1DV DC Modification to Clause 1.1:

1.1DV.1 Circuit breakers used as short-circuit protective devices in combination starters and protected starters shall comply with the requirements of Annex DVA, Table DVA.3, Ref. No. 3. IEC 60947-2, does not apply.

1.1DV.2 Disconnect switches shall comply with the requirements of Annex DVA, Table DVA.3, Ref. No 1. The Standard for Low-voltage Switchgear and Controlgear – Part 3: Switches, disconnectors, switch-disconnectors and fuse combination units, IEC 60947-3, does not apply.

1.1DV.3 Fuses used as short-circuit protective devices in combination and protected starters shall comply with the requirements of Annex DVA, Table DVA.3, Ref. No. 2.