A power outage is annoying in itself, but doing important work on your computer can be a disaster as work that has not been saved is lost. Laptops in this sense have an advantage over desktop computers - they have a built-in battery. They also came up with a solution for a PC - a UPS - an uninterruptible power supply.
An uninterruptible power supply for a computer is needed for the correct completion of programs and the preservation of important data by the user in case of an emergency power outage. The UPS is not designed to provide long-term power to the computer. The operating time is on average 15 minutes, which is quite enough to close and save everything. Longer battery life requires powerful batteries, which makes the device very bulky and expensive.
Depending on the principle of operation, UPSs are divided into three types:
- backup UPS;
- line-interactive UPS;
- UPS with double conversion.
When buying such a device, remember that the power of the UPS is indicated in volt-amperes - VA, and the power of the connected devices in watts - W. To convert one value to another, you need to multiply the number of VA by a factor of 0.7 and you will get watts. For example, multiply the power of a 1000 VA UPS by 0.7 - you get 700 watts. Therefore, taking into account the required power reserve, such a UPS can be connected to a load of up to 500 W.
When choosing a UPS, you should also pay attention to the battery life at full load, the availability of short circuit protection in the network and the connected device, the ability to replace batteries, the presence of a display and what information is displayed on it.
Redundant UPS
In the event of a utility power failure or severe power outage, the standby UPS switches to batteries. The switching time is less than 10 milliseconds, which is sufficient for smooth operation of the computer. Due to the possibility of switching the UPS to battery power during power surges, it is advisable to turn on the network stabilizer before it, this will significantly extend the battery life.
Redundant power supplies are the most common type of UPS because they are relatively cheap, high efficiency and low noise level. The battery life is from 5 to 10-15 minutes and depends on the power of the connected device. Therefore, it is necessary to purchase a device with a 20-30% power reserve.
Line Interactive UPS
Uninterruptible power supplies of this type include a voltage stabilizer, therefore, they have an advantage over the previous ones, but they also cost significantly more.
These devices only switch to battery power when there is a complete power outage, so the batteries last much longer. They are also more economical, have a longer battery life - up to 20 minutes, higher protection of connected devices. Disadvantages - high price and noise from the stabilizer cooling fan.
Double-conversion UPS
These are the most complex and expensive devices. The principle of operation is to convert alternating current to direct current and then back to alternating current. The output is a perfect sine wave and a voltage of exactly 220 volts. The batteries are permanently connected, so these UPSs have zero transfer times.
Designed to power expensive equipment, server stations and computer networks, which do not allow even a short interruption of work. Disadvantages - very high cost, low efficiency, high heat generation, increased noise.
