定价： 235元

定价： 353元

定价： 216元

定价： 216元

定价： 216元

定价： 216元

定价： 0元 / 折扣价： 0 元

定价： 0元

This recommended practice is limited to auxiliary devices associated with rotating electrical machines operating in Class I, Division 2 or Zone 2 areas or Class II, Division 2 areas or Zone 22 areas under the practice of NFPA 70, National Electrical Code® (NEC®) and CSA C22.1, Canadian Electric Code (CE Code).6 This recommended practice is not an attempt to rewrite or otherwise supersede applicable sections or clauses of these noted documents or any other codes or ordinances. Rather, it is… read more intended to serve as a supplement to existing codes that in this area may not be sufficiently specific to serve as a guide to good engineering practice. read less

定价： 56元 / 折扣价： 48 元

This recommended practice is limited to auxiliary devices associated with rotating electrical machines operating in Class I Division 2 and Zone 2 or Class II Division 2 and Zone 22 areas, as classified under the practice of the National Fire Protections Association (NFPA) standard NFPA 70, National Electrical Code(R) (NEC(R)) and the Canadian Standards Association (CSA) standard CSA C22.1, Canadian Electrical Code (CE Code). This recommended practice is not an attempt to rewrite or otherwise… read more supersede applicable sections or clauses of these noted documents or any other codes or ordinances. Rather, it is intended to serve as a supplement to existing codes that in this area may not be sufficiently specific to serve as a guide to good engineering practice. read less

定价： 59元

定价： 0元 / 折扣价： 0 元

This standard presents general consideration for special HVP systems intended to protect telecommunications facilities serving electric supply locations. This standard contains material common to all of the IEEE 487(TM) family of standards including fundamental protection theory and basic electrical protection concepts and designs.

定价： 158元 / 折扣价： 135 元

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… read more 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. read less

定价： 173元 / 折扣价： 148 元

This standard presents engineering design procedures for the electrical protection of telecommunication facilities serving electric supply locations through the use of metallic wire-line components in part of the telecommunication circuit and optical fiber systems in the remainder of the telecommunication circuit. Other telecommunication alternatives such as radio and microwave systems are excluded from this document.

定价： 110元 / 折扣价： 94 元

This standard presents engineering design procedures for the electrical protection of communication facilities serving electric supply locations through the use of neutralizing transformers. Othere telecommunication alternatives, such as radio and microwave systems, are excluded from this document.

定价： 110元 / 折扣价： 94 元