Operating Principle; Ups State And Operation Mode - Liebert UHA1R-0100 User Manual

Non-authorized personnel are prohibited from opening the UPS chassis cover.

1.4 Operating Principle

The operating principle of the UPS is shown in Figure 1-4.
Bypass
1. The UPS is composed of mains input, I/O filter, rectifier/PFC, inverter, bypass, internal charger, battery input and
UPS output.
2. When the mains is normal, close the bypass MCB, and the internal charger will charge the battery. Before the UPS
is turned on, the output voltage is zero. After the UPS is turned on, the electronic transfer switch connects the inverter
to the load, and the mains supplies DC power to the inverter through the rectifier/PFC circuit. The inverter then
converts DC power into pure sine wave AC power, and supplies the AC power to the load through the electronic
transfer switch.
3. When the mains is abnormal, the rectifier/PFC circuit boosts the battery voltage and supplies it to the inverter. The
inverter then converts it into pure sine wave AC power, and supplies the AC power to the load through the electronic
transfer switch.
4. After the mains restores, the UPS will automatically transfer from Battery mode to Normal mode, the mains
supplies DC power to the inverter through the rectifier/PFC circuit, and then the electronic transfer switch supplies the
AC power to the load.

1.5 UPS State And Operation Mode

The UPS state and operation mode include: Normal mode, Bypass mode, Battery mode, ECO mode, Fault state and
Maintenance Bypass mode.
The operation schematic diagrams of Normal mode, Bypass mode, Battery mode and Maintenance Bypass mode are
shown in Figure 1-5.
Only when the UPS output power distribution unit (POD for short) is configured, the Maintenance Bypass mode is valid.
Mains
Input filter
L1
Input filter
L2
L3
N
PE
Figure 1-4 UPS operating principle
Liebert ITA 10kVA UPS User Manual
®
警告 危 险
Note
Bypass MCB
Rectifier/PFC
Internal
Battery input
charger
警告 危 险
Note
Chapter 1 Product Introduction
Output
Inverter
L1 output
3