Because the pc system isnt using it its using 110

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the most part, the battery doesn't need to be charged all the time. Because the PC system isn't using it. It's using 110 volt wall current. Now, if the current coming out of the wall drops below about 80 volts or so, like in a brownout or a blackout, there's a switch inside the UPS that breaks the connection here, and then converts over to the battery. So then the PC starts running off the battery. Because you're not continually draining and recharging the battery, the batteries in an offline UPS tend to last a lot longer than the batteries in an online UPS. However, an offline UPS has one critical disadvantage. That is, if the power drops below 80 volts, thenthe power is switched from the wall current to the battery. During this switch there is a millisecond of time that the power is turned off. They're hoping that inside the power supply of the PC that there is enough AC current stored up to keep the system running for just a few milliseconds while the power switches over. For the most part, this usually works. However, if your power supply is too small for your system, and it is barely keeping up with the demand, you could have a problem. This is why many companies use an online UPS for really critical systems, like servers. Because they don't want the power to go down on a server. For workstations, many people use an offline UPS because they're less expensive and if the system goes down, it isn't as painful. Use your organization's values to decide which of these you want to use. Choosing a UPS 6:46-7:30 When selecting a UPS, look at the battery power. Some UPS devices have larger batteries, and can supply power for a longer period of time. Look on the box for a rating to know how long the battery will last. It will say something like this system will power one PC for 20 minutes. Many of the less expensive power supplies will keep a single PC running for about 20 minutes. However, this time tends to be overrated. A general rule of thumb is to plan for about half of the time advertised and use the rest of the time as a cushion. Also, if you plug more than one PC into the power supply then you need to cut the amount of time in half again. Keep these factors in mind as you choose a UPS. Be sure you get one that will provide the power you need, such as an offline or online. And that will provide that power long enough. Configuring a UPS 7:31-8:20 Now, let's take a look at how to configure a UPS system. Let's say that you just bought a UPS. What do you do with it when you get it home? Well, there's a couple of things you need to do. First, plug it into the wall outlet. Most UPS documentation says to charge the UPS for 12 to 24 hours before you use it. You need to charge the battery before you start plugging things into it. When this battery is fully charged, plug the system you're protecting into one of the outlets on the UPS.
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  • Spring '14
  • Electrostatics, power supply, static electricity, Electrostatic discharge

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