本指南涵盖额定功率为0.18 kW（1/4 hp）及以上的三相和单相交流同步和感应电机。主要重点是在国家电气规范（R）（NEC（R））（NFPA 70-2020）和加拿大电气规范（R）（CE规范（R））（CSA C22.1-2021电气装置安全标准）所涵盖的2区和I类2区位置使用开放式或非防爆或非防火封闭式机器（如适用）。包括表面温度测试方法以及正弦波和非正弦波应用。包括防止表面温度过高和火花的预防措施。为了帮助缓解热表面温度和火花，本文件提供了在2区和I类2区位置选择、操作和维护机器的指南。 本指南不包括交流绕线转子电机和直流电机。安装在NFPA 70-2020或CSA C22规定的2区和I类2区以外位置的机器。本指南不包括1-2021年。本文件不是规范，也不打算用作购买电机的规范。本文件中的电压中断为1000 V及以下，以及1000 V以上。

Three-phase and single-phase ac synchronous and induction electric machines in ratings 0.18 kW (1/4 hp) and larger are covered in this guide. Primary emphasis is on the use of open or nonexplosionproof or nonflameproof enclosed machines in Zone 2 and Class I, Division 2 locations as covered in National Electrical Code(R) (NEC(R)) (NFPA 70-2020) and Canadian Electrical Code(R) (CE Code(R)) (CSA C22.1-2021 Safety Standard for Electrical Installations) as applicable. Surface temperature test methods and sine wave and non-sine wave applications are covered. Precautions against excessive surface temperatures and sparking are included. To help mitigate hot surface temperatures and sparking, this document provides guidance for selecting, operating, and maintaining machines in Zone 2 and Class I, Division 2 locations. This guide does not cover ac wound rotor machines and dc electric machines. Machines installed in locations other than Zone 2 and Class I, Division 2 as covered in NFPA 70-2020 or CSA C22.1-2021 are not covered in this guide. This document is not a specification and is not intended to be used as a specification for purchasing electric machines. The voltage breaks in this document are 1000 V and less, and over 1000 V.