定价： 144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 non-explosion proof or non-flame proof 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 C22.1-2018 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 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 - 2018 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： 0元 / 折扣价： 0 元

This recommended practice presents engineering design procedures for the electrical protection of communication facilities serving electric supply locations using optical fiber systems. Services utilizing wire-line protection systems are addressed in IEEE Std 487™-2007. 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 telecommunication facilities serving electric supply locations through the use of optical fiber systems for the entire facility. Other telecommunication alternatives such as radio and microwave systems are excluded from this document.

定价： 61元 / 折扣价： 52 元

定价： 149元 / 折扣价： 127 元

Part I of the guide discusses the effects of various aspects of the ac/dc interactions on the design and performance of dc schemes where the ac system appears as a high impedance at the ac/dc interface bus; i.e., low and very low short-circuit (short-circuit ratio [SCR]) conditions. AC systems having zero or inadequate mechanical rotational inertia, such as island schemes with no or with limited local generation, are also considered. Environmental, siting, and construction issues are not addressed. General issues, such as steady-state reactive compensation and ac and dc filter requirements, are not in the scope of this guide, but would be included in a complete study for a particular dc scheme design. In order to assist those not familiar with dc transmission and convertors, a brief description of basic rectifier and inverter operation is given in Annex A of Part I. Part II of this guide, which is bound together with Part I, considers how the ac/dc interaction phenomena described in Part I should be taken into account in the planning and the preliminary design of ac/dc systems having low or very low SCR values.

定价： 169元 / 折扣价： 144 元

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

定价： 55元 / 折扣价： 47 元

定价： 149元 / 折扣价： 127 元

定价： 0元

定价： 67元

This recommended practice is limited to auxiliary devices associated with rotating electrical machines operating in Division 2 or Zone 2 areas, classified as Class I under the practice of ANSI/NFPA 70 or Zone 2 areas classified under the practice of IEC/CENELEC EN60079-10:1996.

定价： 110元

This standard presents engineering design procedures for the electrical protection of telecommunication facilities serving electric supply locations through the use of optical fiber systems for the entire facility. Other telecommunication alternatives such as radio and microwave systems are excluded from this document.

定价： 81元 / 折扣价： 69 元

定价： 302元

定价： 311元

定价： 227元