Power failures, load shedding and low voltage have become our constant         companions. Over the years, the situation has worsened instead of improving. The business and work schedules get affected, students lose precious study time, and the family’s entertainment time disappears, not to mention the inconvenience caused during the winter. The problem is compounded with the popularity of PCs in the modern house holds.   Commercial power supply is not capable of providing clean and consistent electric power demanded by sensitive equipment. Sensitive equipment requires a consistent supply of power of the correct specifications for their operation, hardware protection, continuity of process, storage and transfer of information, and safety of personal Computer network communication links, electronic medical equipment, industrial process control, remote installations like offshore operations, online applications such as airline reservations etc., are examples of such critical loads. Beyond any dispute, the installation of an Uninterrupted Power Supply (UPS) system is now days accepted as being a vital element in the protection of sensitive equipment.    

BATTERY-LIFE OF THE UPS SYSTEM:-

    The most critical part of the UPS system is the battery. The battery often represents half the original cost of   UPS system. It is the weakest link in the UPS system. An incorrect selection of the battery type may reduce the initial cost but would adversely affect the overall life of the system.   The battery life is determined by the UPS service conditions. For online UPS systems, the battery remains on floating charge for longer time. Float performance characteristics has a strong influence on battery life. Prolonged breakdowns can cause the battery to deep discharge several times in a week if not in a day.  This in turn affects battery life drastically, as a thumb rule; a deep discharge below 80% battery capacity reduces the life of the battery by 25%.      

BLOCK DIAGRAM OF UPS SYSTEM:

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