ULcompliant control panels technical guide（ULcompliant控制面板技术指导）.pdf

Control Panel Technical guide How to ensure trouble-free approval of your UL-compliant control panels This guide* explains certain points requiring special attention for trouble-free export sales. *This guide replaces neither the standards (including UL 508A) that electrical equipment must comply with nor the requirements of standard professional practice. It is the responsibility of the equipment manufacturer to ensure compliance with all applicable standards. Excerpts from UL 508A (Standard for Safety for Industrial Control Panels) are the property of Underwriter’s Laboratories Inc. Contents UL compliance = Your visa for the United States p. 4 Designing and building control panels for the U.S. market p. 4 Applicable standards in North America p. 5 1 UL standards and control panel design p. 6 Definition of electrical circuits as per standard UL 508A p. 6 Certifications required for products p. 7 UL standards and circuit design p. 8 2 Design of a motor circuit as per standard UL 508 part IV and UL 508A p. 8 Recommended functions and devices p. 8 Standardised typical solutions for motor circuits p. 9 Sizing single-motor protective devices p. 10 Design of a single-motor circuit controlled by a variable-speed drive p. 11 Protecting a group of motors using a single device p. 12 Typical solutions for protection and control of a group of motors p. 13 Sizing single-load protective devices for other circuits p. 14 Sizing the protection for a control panel incomer p. 15 3 Selecting products for UL control panelsp. 16 Feeder circuits / panel incomer p. 18 Circuit breakers p. 18