短路电流额定值的重要性

2017/04/24


对于寻求打入北美市场的全球机器制造商而言,突破文化和地域壁垒已属不易。但是,与遵守当地标准和法规相比这根本不算什么。

不同地区使用不同方法确定系统的短路电流额定值。这给试图打入北美市场的 OEM 和系统集成商带来了巨大的困难。

从设计、开发到安装和操作,各类电气标准影响着机器生命周期的每个阶段。如果不在规划阶段考虑这些标准,将更加难以确定成套工业控制面板的短路电流额定值。

那么,为确保制造合规的机器和控制机柜,机器制造商需要知道什么?

了解相关法规

尽管部分北美电气标准在十几年间逐渐与全球标准并轨,但仍然有许多差异要考虑。每一家机器制造商都应熟悉以下三个标准:

· UL 508A,工业控制机柜标准

· NFPA 70,美国国家电气法规 (NEC)

· NFPA 79,工业机械电气标准

随着机器和机柜制造商日益熟悉这些标准,他们开始认识到这些标准和国际标准之间存在的差异,以求开发全球性的产品组合。

规范化

任何机器或机柜设计项目都应以明确的要求和规范为起点。

向最终用户客户索取和确认的信息类型包括:

· 电源,包括电压、相位、频率、系统接地和所需的短路电流额定值

· 工作条件,如温度、振动和环境因素

· 设备负载,如电机、驱动器、加热器和变压器

· 功能描述,包括操作顺序和操作员界面

· 适用标准和认证,包括当地要求

书面化

机器或机柜制造商最基本且最重要的工作之一是记录关键项目要素,以作为提案流程的一部分。这些记录应包括客户规范和要求、适用国家和地方标准以及所提议的机器解决方案和项目评估。将所有内容书面化有助于澄清机器设计的各个方面。

完整的文档在提案流程之外也发挥着关键作用。机器和机柜制造商应考虑在其材料清单以及审查和测试文档中加入专用装配和接线说明。其中包括创建设计审查和测试清单,以及拍摄完整控制机柜的数码照片。

善用资源

机器和机柜制造商可以利用丰富的工具、培训、支持及文献帮助其服务北美市场。

罗克韦尔自动化提供的 全球短路电流额定值 (SCCR) 选型工具 就是很好的例子。这种在线工具为电路中使用的所有电源器件提供协调高故障 SCCR 额定值,有助于节省查找和确定这些额定值的时间和精力。该工具的数据基于 UL 或 IEC 标准。

 

繁杂的标准和法规让人望而生畏,但它们不应成为在新市场取得成功的障碍。了解关键标准有助于 OEM 和面板制造商满足合规性要求,并提高其在北美市场的竞争优势。

Video: The Global Short Circuit Current Ratings (SCCR) Selection Tool provides coordinated high fault branch circuit solutions for motor starters, soft-starters and component drives.

Get Specific

Any machine or panel design project should begin with well-defined requirements and specifications.

Types of information that should be requested and confirmed with the end-user customer include the following:

  • Power supply, including voltage, phase, frequency, system grounding and required short-circuit current rating
  • Operating conditions, such as temperature, vibration and environmental factors
  • Loads for devices, such as motors, drives, heaters and transformers
  • Functional descriptions, including sequence of operation and operator interfaces
  • Applicable standards and certifications, including local requirements

Write It Down

One of the most basic but important things a machine or panel builder can do is document key project elements as part of the proposal process. These notes should include the customer’s specifications and requirements, applicable national and local standards, and proposed machine solution and project estimate. Putting everything into writing helps clarify all aspects of the machine design.

Thorough documentation also plays a critical role beyond the proposal process. Machine and panel builders should consider including special assembly and wiring instructions in their bill of material, as well as review and test documentation. This can include creating design-review and test checklists, and taking digital photos of completed control panels.

Be Resourceful

Machine and panel builders can take advantage of a bounty of tools, training, support and literature that can help them serve the North American market.

One example is the Global Short-Circuit Current Ratings (SCCR) Selection Tool from Rockwell Automation. This online tool provides coordinated, high-fault SCCR ratings for all power devices used in a circuit, helping save time and effort when finding and determining these ratings. The tool’s data can be based on either UL or IEC standards.

While standards and codes can be daunting, they shouldn’t be a barrier to success in a new market. Understanding key standards can help OEMs and panel builders meet compliance requirements and improve their competitive edge in North America.


发布 April 24, 2017 作者 Sarah Larson, Commercial Programs Manager, Rockwell Automation