3.0 Working Principle
3.1 In AC mode
When UPS is in normal working mode, AC goes through the filter and the harmful
waves are filtered. After that, AC charges the battery and meanwhile, passes UPS
AVR and the filter and provide power for the equipment.
3.2 AC Failure
When AC fails, the battery will supply power to the inverter and then passes filter and
provide power for the equipment, ensuring the continuous power supply.
3.3 Connections of the UPS
The UPS has the following connections:
• 1 RS232 serial port (only for EM3941 and EM3942)
• 1 USB port
• 1 AC connection (Power input) (only for EM3942)
• Output connections (the number differs per model)
