This Technical Note discusses many common misunderstandings about the function of the neutral wire and its relation to power problems. The subjects of dedicated lines, phase reversal, isolation transformers, and grounding are addressed. Various myths are described and criticized.

This white paper examines and challenges the claims made in literature regarding the alleged high susceptibility of computers to common mode noise.

As power densities continue to increase in today’s data centers, heat removal is becoming a greater concern for the IT professional. Unfortunately, air conditioning terminology routinely used in the cooling industry is unnecessarily complicated. This complexity makes it difficult and frustrating for IT professionals to specify cooling requirements and even makes it difficult to discuss current cooling system performance with contractors, engineers, and maintenance personnel. This paper explains cooling terms in common language, providing an essential reference for IT professionals and data center operators.

本白皮书旨在介绍供电中断对于交流供电系统可用性和正常运行时间的影响，提供有关实际环境中正常运行时间的量化数据，包括UPS对于正常运行时间的影响。

本文档介绍如何估算数据中心内的 IT 设备和其他设备（如 UPS 等）的发热量，以确定空调系统的冷却容量。此外，本文档还包含一些常用的转换系数和指导性设计值。

Most AC power capacitor failures experienced in large UPS systems are avoidable. Capacitor failures can give rise to UPS failure and can in some cases cause critical load drops on stand-alone and paralleled systems. AC capacitor failures have historically been ascribed to unavoidable random failure or supplier defect. However, recent advances in the science of capacitor reliability analysis show that capacitor failures can be controlled by system design. This paper explains AC capacitor failure mechanisms and demonstrates how UPS designers and specifiers can avoid most common AC capacitor failures and the associated consequences.

Signal reference grids are automatically specified and installed in data centers despite the fact that they are no longer needed by modern IT equipment. Even when installed, they are typically used incorrectly. This paper explains the origins of the signal reference grid, the operating principles and limitations, and why they no longer are needed.

The lifecycle cost of different UPS battery technologies is compared. The costs associated with the purchase of batteries, the infrastructure costs, and the costs associated with inflexibility to meet changing requirements are discussed and quantified.

在选择新址或评估现有场地时，必须要对一系列的风险 因素加以考虑来达到最优的业务的可用性。我们需要清 楚了解地理/地域、场地、建筑和经济等方面的风险， 尽量减少宕机对企业的业务造成影响。在本白皮书中， 我们将介绍选择新址或评估现有场地的方法，定义影响 业务可用性的常见风险并提出规避这些风险的办法。

数据线的电力瞬变（浪涌）现象可能会损坏企业和家庭办公环境中的计算设备。许多用户十分重视供电线路浪涌带来的风险，却忽视了数据线浪涌的危害。本白皮书将介绍瞬变电压是如何产生的、瞬变电压对用电设备具有哪些破坏性影响以及浪涌抑止设备如何保护用电设备免受浪涌的影响。