Uninterruptable Power Supply (UPS) is an important component in the control system. It is useful for temporarily storing electrical energy. Energy storage is carried out in the UPS batteries. These batteries have a certain capacity according to the load requirements. UPS batteries only last an average of 2 hours if it does not get a supply voltage from the outside. Failure in the distribution of this voltage can cause exhaustion of the UPS batteries so some components in the control system can not work. To avoid this, the UPS system should get a backup voltage source. Backup voltage source is taken from an existing generator set. Making backup voltage is accompanied by a control system to ensure security in the event of transferring voltage from the main voltage source to the backup voltage. The control system used is conventional control system using the contactor. We hope it can transfer voltage from main to the backup voltage easily if there is problem with main voltage from main power.
Key words: UPS, UPS battery, backup voltage, efficiency, safety