低压开关设备和控制设备标准.第4-2部分:接触器和电动机起动器.交流半导体电动机控制器和起动器SUL 60947-4-21范围和目的.本标准适用于控制器和起动器，可能包括一系列机械开关装置，用于连接电路，额定电压不超过1000 V a.c.本标准描述了带或不带旁路装置的控制器和起动器。本标准中涉及的控制器和起动器通常不用于中断短路电流。因此，适当的短路保护（见8.2.5）应构成安装的一部分，但不一定是控制器或启动器的一部分。在这种情况下，本标准给出了与单独短路相关的控制器和起动器的要求- 保护电路。本标准不适用于:交流电机在非正常转速下的连续运行；半导体设备，包括控制非电机负载的半导体接触器（见IEC 60947-1的2.2.13）；IEC 60146所涵盖的电子交流电源控制器。控制器和起动器中使用的接触器、过载继电器和控制电路设备应符合其相关产品标准的要求。如果使用机械开关设备，则应满足其自身IEC产品标准的要求，以及本标准的附加要求。本标准的目的是说明以下内容:控制器、起动器和相关设备的特性； 控制器和起动器应符合以下条件:其操作和行为；介电性能；适用时，其外壳提供的防护等级；他们的建设；旨在确认这些条件已得到满足的试验，以及这些试验所采用的方法；随设备提供的信息，或在制造商的文献中提供的信息。

Standard for Low-Voltage Switchgear and Controlgear - Part 4-2: Contactors and Motor-Starters - AC Semiconductor Motor Controllers and StartersUL 60947-4-21 Scope and objectThis standard applies to controllers and starters, which may include a series mechanical switching device, intended to be connected to circuits, the rated voltage of which does not exceed 1 000 V a.c.This standard characterizes controllers and starters with and without bypass means.Controllers and starters dealt with in this standard are not normally designed to interrupt short-circuit currents. Therefore, suitable short-circuit protection (see 8.2.5) should form part of the installation, but not necessarily of the controller or starter.In this context, this standard gives requirements for controllers and starters associated with separate short-circuit protective devices.This standard does not apply to:continuous operation of a.c. motors at motor speeds other than the normal speed;semiconductor equipment, including semiconductor contactors (see 2.2.13 of IEC 60947-1) controlling non-motor loads;electronic a.c. power controllers covered by IEC 60146.Contactors, overload relays and control circuit devices used in controllers and starters should comply with the requirements of their relevant product standard. Where mechanical switching devices are used, they should meet the requirements of their own IEC product standard, and the additional requirements of this standard.The object of this standard is to state as follows:the characteristics of controllers and starters and associated equipment;the conditions with which controllers and starters shall comply with reference to:their operation and behaviour;their dielectric properties;the degrees of protection provided by their enclosures where applicable;their construction;the tests intended for confirming that these conditions have been met, and the methods to be adopted for these tests;the information to be given with the equipment, or in the manufacturer's literature.