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    UPS Handbook
    UPS Handbook
    UPS Handbook
    Ebook141 pages1 hour

    UPS Handbook

    By Robert DeLauter

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    About this ebook

    Not an engineer, but need to know the basics of battery backup power? UPS Handbook breaks down the complex world of Uninterruptible Power Supply systems into simple-to-understand language. If you need to know the basics of UPS systems but not the expertise of how to repair them, this book is for you.

    ·   &nbsp

    LanguageEnglish
    PublisherQuirauk Mountain Publishing
    Release dateNov 1, 2020
    ISBN9781735942018
    UPS Handbook

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      Oct 8, 2023

      It is very fantastic references than other references so I love to learning this reference

    Book preview

    UPS Handbook - Robert DeLauter

    Before We Begin

    How to Use This Book

    As with any book, a person could read it from cover to cover. However, I imagine it being used as more of a resource. Please take a few moments to review the table of contents and read the sections you need to understand at the moment.

    I hope that you not only pick up useful information but are also slightly entertained  by the material provided. Although few people typically find engineering books entertaining, I’ve tried to make the material interesting and perhaps even humorous from time to time.

    This book does not go into deep detail on many subjects, but instead covers the basics and allows the reader to speak the same language as others in the industry.

    Feel free to contact me with any questions or feedback.

    rob@robdelauter.com

    Safety

    Reading this book does not provide the qualifications to work on or near electrical equipment, including UPS systems. UPS systems are complicated and power is supplied from multiple sources. It’s critical that only people trained in the electrical industry service this equipment. Unqualified persons performing electrical work can result in severe injury, including death.

    Operation can be completed by individuals not electrically qualified; however, they must be trained in how to work the specific system. Each system functions differently and mis-operation can damage the system and lead to a loss of power to the critical load.

    I

    The UPS System

    1Introduction

    What is an uninterruptible power supply—or UPS system—and why do we need one? If you are reading this book, you probably have a basic understanding of its purpose and necessity.

    Critical equipment, such as phone systems, IT equipment, and fiber optics require continuous power to operate. If they lose electrical power for even a fraction of a second, they will shut down. Often it takes minutes or even hours to restart them. Sometimes there is damage to the equipment that requires repairs before the system will work again.

    Facebook, Amazon, banks, and credit card companies use UPS systems to keep their operations running twenty-four hours a day, seven days a week, 365 days a year.

    Television and radio stations also use UPS systems to be sure they can transmit continuously.

    There is a good chance that your company has a UPS system of some size to keep your email and interoffice servers working in the event of a power problem.

    What is a Static UPS System?

    The Institute of Electrical and Electronics Engineers (IEEE) defines a Static UPS system as an electronically controlled solid-state system designed to provide an alternate source of conditioned, reliable, and break-free electrical power to a user’s equipment. So, what does this mean to non-engineers?

    As its name implies, it is a system that provides uninterrupted power. It is an electrical device that supplies constant power to critical load equipment. Put another way, a UPS system is a device that, when the utility power fails, ensures that your computers keep humming along. But it is not always computers; it can be any electrical equipment that can’t afford to lose power.

    When I interview someone for a field service position, one of my first questions is, Have you reviewed what we do here? Nine out of ten times the answer is yes, you do something with battery backup. From this I explain what a UPS system is.

    I use a simple black box with two inputs and one output. The inputs are normal alternating current (AC) power and emergency direct current (DC) power, while the output is AC power that supports critical electrical equipment during a power outage. The UPS system is provided input power from an external source, normally the utility company. (See Figure 1.)

    Figure 1

    If the UPS system senses a loss of input power, it will automatically switch to battery power and keep the critical load operating. How this switch occurs depends on the type of

    UPS topology, which we discuss more in the chapter UPS System Topologies.

    UPS System or Generator?

    A common question asked is, I have generator; why do I need a UPS system? Or the reverse, If I have a UPS system, why do I need a generator?

    A UPS system and a generator are different tools, and each should be used for its specific purpose. Like all tools, you can use the wrong one and do the job, but not as effectively as if you made the correct choice. UPS systems are used for short outages or as a bridge to get from utility power to generator power. (See Figure 2.)

    Figure 2

    UPS systems primarily use batteries to operate during the outage. Batteries only last so long before they run out of power. As we will discuss later, batteries have a finite life, are expensive, and require maintenance.

    UPS systems have a limited run time while on batteries. They are designed and installed with a specific battery backup time. Often you will hear fifteen minutes, but the length of time depends on how much power is required to perform whatever task is needed if power is not restored in the required time.

    For all intents and purposes, a generator will run as long as it has a fuel source and doesn’t break down. A UPS system can only operate without input power for as long as the batteries last. This translates to: a generator can support the loads as long as necessary, whereas the UPS can only support as long as it has battery power.

    Generators are mechanical devices with engines that take several seconds to start and produce electrical power. The best ones can accomplish this within ten seconds, but in electrical time ten seconds is an eternity, and critical equipment cannot be without electrical power that long.

    If an outage lasts more than a few seconds, the generator will start and begin to supply power to the UPS system. Often there are other systems—such as lights and air conditioning—on the generator. It is not considered good practice for many of these systems to be powered by a UPS system. Air conditioners and other motor loads draw high current when starting, known as inrush. This high inrush current can cause the UPS system to overload and transfer to bypass leaving the load unprotected to power outages.

    2UPS 101-The Basics

    Double Outage: A Case Study

    Several years ago, a colleague and I were completing preventive maintenance on an older UPS system. While transferring the system to External Maintenance Bypass, the system failed, causing a back-feed that tripped an upstream feed circuit breaker. When this circuit breaker tripped, the power to the Automatic Transfer Switch (ATS) and the load was lost. This loss in power to the ATS started the generator.

    It first became apparent to us that the customer misunderstood the system when the facility personnel reset the input circuit breaker, restoring power to the critical load. The UPS system was still in bypass while discussions took place with site operations. Once the circuit breaker was re-closed, the ATS started its thirty-minute clock, checking that input power was good.

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