Power For Your PC

We look at the factors that you should take into account when purchasing a UPS, be it for a large organization containing hundreds of computers, or a

small one with just a handful, and proceed to test 19 UPSs and recommend some of the best ones

Before going in for a UPS, it’s a good idea to analyze the power conditions in your area. Have it analyzed by an experienced person, such as a power engineer, to find out the potential power problems that could hamper your operation in the future. For instance, if you’re located in an industrial area, then chances are that there’ll be a lot of disturbance in the mains voltage caused by the operation of heavy machinery. A heavy motor could cause a sudden dip in the voltage when turned on and vice versa. Therefore, the UPS you buy should be able to regulate the voltage enough to keep the equipment in your office running smoothly. 

You might also need other power conditioning equipment besides the UPS. For this, check the quality of power lines in your area, especially the line supplying power to your organization. If it’s faulty, then it could cause voltage surges or spikes. A surge is a sudden rise in voltage that can attain very high values. It lasts for only a fraction of a second, but since the voltage is so high, it can fry your equipment. Therefore, you may also need to install special surge-protection equipment. A good UPS system would also have surge suppression built-in, and would be able to suppress it within the first half cycle of the incoming voltage. Therefore, check for the surge-suppression quality of a UPS before buying. 

How much power

Before you decide what kind of a UPS to buy, you should size up your requirement. For this, you need to first note down all the equipment you’d like to provide backup to. Some typical systems that need UPS backup are servers, workstations, printers, fax machines, and local PBX. You then need to note down how much power you require. For this, you’ll need to know how much power each device consumes. In most cases, this can be obtained by reading the back plate of an electrical device. You may find the power consumption either in watts or amps. If the power consumption is given in amps, then you need to multiply it with the operating voltage of the electrical device. For instance, if a computer monitor mentions the power consumption to be .3 amps, and operating voltage as 220 volts, then multiplying the two will give you 66 Watts. Now, add up the power consumed by each device to get your total load. You should always go for a UPS that can handle a little more load than the total load in your organization, to leave enough capacity for future growth. Plan for a UPS that can backup around 25 percent more than your rated load. 

Distributed vs centralized power

There are three ways of distributing power in your organization: centralized, distributed, or a combination of both. Centralized power means buying one large UPS for all your equipment. Distributed, is likewise buying several smaller units and placing them across your organization to handle various equipments. The third is going for a large UPS to handle all the general load, and smaller UPSs to handle the critical load. The method you go for depends upon your organization’s span and nature of business. If it’s spread across a large area, then it may not be possible to provide centralized backup. It would be really difficult to carry over the backup power to all the locations.

Therefore, it’s better to go for distributed power kind of a setup, and install multiple UPS units. If it’s a small office with a handful of computers, then you have may find distributed computing to be a cheaper option. That’s because there are a lot of small time UPS manufacturers in the country, so you have a choice of going for the one that gives you the best deal in terms of pricing and support. Centralized backup could prove more economical and reliable for a large organization having lots of equipment located in the same building. So you could install one large UPS to provide backup to all the systems. This would be more manageable than several smaller units scattered across the office. You may also need extra power for critical elements such as servers, networking devices, and other important equipment such as your local PBS, which are crucial to your business. For these, you could go for additional smaller UPS units to provide backup power. Finally, your nature of business determines the kind of power you need. If you’re running say a call center, or you’re a service provider, then you’d want 100 percent guaranteed uptime. For this kind of a setup, you’d need to build redundancy in your power. Most large UPS manufacturers have UPS systems that provide redundant power. The amount of backup is another critical element here. If there’s a power cut, how long will it be before the batteries drain out completely. If there are long power cuts in your area, then you may want to consider going for a long period of backup. For this, you’ll need extra batteries. 

UPS technologies

Once you’ve done your planning, it’s time to decide what kind of a UPS to go for. They are available in three different types of technologies known as off-line, line-interactive, and online. All three give different levels of power protection, and their prices also vary accordingly. 

Offline. This type of UPS system is the simplest of all. When a power cut occurs, an offline system will switch to battery. Due to this switching behavior, there’s a distinct amount of delay before the PC starts getting its power from the batteries. This must be minimal in order to prevent your PC from rebooting. An offline UPS provides square wave output from the batteries. Due to its simplicity of design, an offline UPS is the easiest to manufacture, and therefore the cheapest.

Nowadays, there are many manufacturers that also provide automatic voltage regulation in their offline UPS designs.

Line-interactive. The aim of a line-interactive UPS is to continuously monitor the incoming line voltage and provide a stable output. If there’s a dip or rise in the mains voltage, this type of UPS kicks in the step-up or step-down transformer to increase or decrease the output voltage to the load. It differs from an offline UPS in that it provides a quasi-sine wave output, which is a stepped sine-wave approximation. This type of waveform is better than the square waveform provided by offline

UPSs. 

Online. This is the most complex UPS system and provides the maximum power protection. It always supplies power to the load through the batteries. Therefore, even if there’s a power cut, there’s no switchover occurring, as in the other two technologies. It also gives a constant output voltage that will not dip or rise due to this. Online UPS systems provide the maximum protection, and are therefore the most expensive. These models mostly start at 1

kVA. 

Choose the UPS technology carefully depending upon the type of load you have. Depending upon how critical the load is, you may also need some management features along with a UPS. Many large UPS systems have extensive management capabilities. They can be controlled by software, provide useful information like the percentage of load connected, input/output voltage, and backup time remaining. Nowadays, there’s also hardware available for remote management of UPS systems. So you can check the status of your UPS over the Internet. You can also safely shutdown your systems in case of a power cut. The UPS will inform you via e-mail in case of a power failure or some other problem. These are all convenience features that can help you ensure that power is not a problem on your network. 

Anil Chopra