An UPS is a device which maintains continuous supply of electric power to the connected equipment by supplying power from a battery when main power is not available. UPS supplies current to the system for a particular period of time depending on the capacity of the device. In the event of power failure, using the backup power supply, the system can safely shutdown. This ensures that the files on the system or the system components such as hard disk do not get corrupted due to improper shutdown. A computer can accept a slight difference in the voltage frequency. However, a major difference in the voltage frequency can damage the components of the system. A Backup Power System also known as the UPS is used for protecting the system from these surges. The Battery of the UPS gets charged when the system is powered ON using the main power supply. This stored battery current is used during a power failure.
Types of UPS:
Depending on the features of the Ups they are classified in following types:
Stand by UPS: The stand by UPS remains in standby mode until the battery current is required whether there are power fluctuations or a power failure. When the power returns to normal the UPS stops supplying the electric current to the system.
Line interactive UPS: The Line-interactive UPS keeps a track on the power supply voltage from the power supply junction to the system. If the voltage falls very low than the Ups supplies the power to the system. This is used for the small-scale servers such as web servers, small business or departmental servers.
Online UPS: The Online UPS supplies power to the system from the UPS battery at all the times even when the power supply voltage is at normal levels. The battery gets charged continuously as long as it gets power from the power supply junction. When there is a power failure, the UPS continues to supply power to the system till there is power in the battery.
Selecting a UPS:
Power problems can affect the systems by causing you to loose stored data or damage the system components. To protect the system from sudden power problems, you should use a UPS to overcome these problems. The factors considered before selecting a UPS are load, installation location, cooling batteries and efficiency.
- Load: It is necessary to check the size and the type of the system that needs to be protected by the UPS. Accordingly, the power rating of the UPS can be determined for the system. The maximum power rating of a standby UPS starts from 500 VA to 1.5KVA.
- Installation location: An UPS system has a noise level between 50-60dba and releases heat while working. As a result, it needs to be placed separately and away from the work area. This factor is considered in case of an office work area.
- Cooling: When a system uses UPS for the backup power, the cooling facility such as an air cooler should be provided for the system as well as for the UPS.
- Batteries: The Batteries of UPS are placed in a separate cabinet along with the UPS or may be placed inside the UPS. If the battery of the UPS gets damaged, you must replace the batteries immediately with a replaceable battery pack.
- Efficiency: The efficiency of the UPS system will calculate the operating costs of the UPS. If the UPS works efficiently, operating cost of the UPS will be less.
Features of UPS:
- Form factor: A form factor refers to the general shape and size of the UPS. The UPS is available in standalone model and rack-mount model. Stand-alone models of UPS are placed on floor outside the system. The rack-mount models of the UPS are placed on the metal racks, thus saving the floor space. These models of UPS are used when a system is placed on a rack and the UPS is placed just below the system. These are used in industrial and commercial applications.
- Capacity and runtime: The run time of a UPS is the amount of time the battery of the UPS provides electric current to the system in case of power failure. The capacity of Ups means the capacity of the battery to supply electric current to the system for the maximum amount of time. It also means that the ability of the circuits and wires of UPS to bear the load of the electric current. The model name of the UPS displays the capacity of UPS. For e.g. An UPS of 650VA has the capacity of 650.
- Self-test: The Self-test feature of UPS ensures that the UPS is functioning properly and the system is well protected. The UPS tests itself when it is turned ON and then does it periodically during the week. During the self-test period of the UPS, it emits some tone with a flash of light on the indicator. The self-test feature of the UPS can be controlled with the help of UPS control software.