There two main maintenances required for the UPS that consists if preventive and remedial maintenance. The Preventive maintenance consists of planned list of activities. Performing these preventive activities keeps the UPS in healthy condition and helps to prevent breakdowns. On the other hand; The Corrective maintenance is performed as a result of a breakdown. This reactive maintenance troubleshoots and gets the unit working over again.The fundamental static UPS system consists of a rectifier charger, inverter, static switch, and battery. The rectifier provides the DC power to the inverter, receives the normal AC power supply and charges the battery. In order to provide the intended loads, the inverter converts the DC power to AC power. Upon failure of the main AC power source or the rectifier, the DC power will normally be provided from the rectifier and from the battery. The inverter will supply the loads under normal conditions. In the event of the malfunction of the inverter, the static switch transfers the load to an alternate ac source.