The full name is Emergency (emergency) Power (electricity) Supply (supply), is an emergency power supply used in today's important buildings for power protection and fire safety. It is mainly composed of input and output units, charging modules, battery packs, inverters, monitors, output switching devices and other components.　The principle is as follows: when the utility power is normal, the utility power will supply power to the important loads through the output switching device, and at the same time, the charger will charge or float charge the batteries; when the utility power is cut off or the voltage is out of the range of power supply, the controller will start the inverter, and at the same time, the output switching device will switch the utility power supply to the inverter power supply immediately to provide emergency power supply for the load equipments; when the utility power recovers, the emergency power supply will be resumed to supply power to the utility power. When the utility power is restored, the emergency power supply will return to the utility power supply.　 Stable Bo EPS emergency power supply schematic diagram EPS is to solve the emergency lighting, accident lighting, fire facilities and other primary load power supply equipment as the main goal, to provide a fire code in line with the emergency power supply system with an independent circuit, the system is able to provide emergency power supply in the emergency state, used to solve the problem of lighting power or only one way of the utility lack of a second power supply, or instead of the generator set constitutes the second power supply, or to do the third power supply occasions. The system can be used to solve the problem of lighting or only one utility power without a second power supply, or replace the generator set to form the second power supply, or be used for the occasions that need the third power supply.