IEC 60470 pdf download High-voltage alternating current contactors and contactor-based motor-starters
1.1 Scope and object
This International Standard is applicable to a.c. contactors and/or contactor-based motor-starters designed for indoor installation and operation at frequencies up to and including 60 Hzon systems having voltages above 1 00o v but not exceeding 12 000 v.
lt is applicable only to three-pole contactors and starters for use in three-phase systems,and single-pole contactors and starters for use in single-phase systems.Two-pole contactors andstarters for use in single-phase systems are subject to agreement between manufacturerand user.
Contactors and/or starters dealt with in this standard are not normally designed to interruptshort-circuit currents. Therefore，suitable short-circuit protection (see 220.127.116.11 and note 2below) forms part of the installation, but not necessarily of the contactor or the starter.
ln this context,this standard gives requirements for
contactors associated with overload and/or short-circuit protective devices (SCPD);
starters associated with separate short-circuit protective devices and/or with separateshort-circuit and integrated overload protective devices;
contactors or starters combined，under specified conditions，with their own short-circuitprotective devices.Such combinations, for example combination starters (see 18.104.22.168),are rated as units.
Contactors intended for closing and opening electric circuits and, if combined with suitablerelays, for protecting these circuits against operating overloads which may occur therein, arecovered in this standard.
This standard is also applicable to the operating devices of contactors and to their auxiliaryequipment.
Motor-starters intended to start and accelerate motors to normal speed, to ensure continuousoperation of motors，to switch off the supply from the motor and to provide means for theprotection of motors and associated circuits against operating overloads are dealt with.
Motor-starter types included are
– direct-on-line starters;
– reversing starters;
– two-direction starters;
– reduced kVA (voltage) starters;
– auto-transformer starters;
– rheostatic starters;
– reactor starters.
This standard does not apply to
– circuit-breaker-based motor-starters;
– single-pole operation of multi-pole contactors or starters;
– two-step auto-transformer starters designed for continuous operation in the starting position;
– unbalanced rheostatic rotor starters, i.e. where the resistances do not have the same value in all phases;
– equipment designed not only for starting, but also for adjustment of speed;
– liquid starters and those of the “liquid-vapour” type;
– semiconductor contactors and starters making use of semiconductor contactors in the main circuit;
– rheostatic stator starters;
– contactors or starters designed for special applications.
This standard does not deal with components contained in contactors and contactor-based motor-starters, for which individual specifications exist.
NOTE 1 Thermal electrical relays are covered by IEC 60255-8.
NOTE 2 High-voltage current-limiting fuses are covered by IEC 60282-1 and IEC 60644.