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SunLight Series UPS User Manual
The S.T.S will transfer back to the inverter automatically when the overload condition has been cleared. If
the inverter fails internally, the unit switches to bypass within a few milliseconds.
Rectifier :
The first stage of the UPS. It supplies the DC bus voltage, which is necessary for operating the
inverter by rectifying line voltage.
Inverter :
It is made by utilizing the latest technology of power transistor (IGBT) and pulse width
modulation (PWM). Inverter converts dc bus voltage into an alternative voltage like line voltage. And
provides this voltage and frequency being fixed.
Static Transfer Switch (static by-pass) :
Static transfer switch is an electronically controlled switching
circuit checked by main controller board. In case of inverter overload or any other faults, STS transfers
the critical load to the mains without any interruption.
Mechanical Transfer Switch :
The mechanical transfer switch consists of a manually operated switch.
When the UPS is switched off due to failure or maintenance, it feeds critical loads from mains.
Battery Group :
It keeps dc voltage, which is necessary for the inverter , as a reservoir dc power supply
in case of mains failure.
Battery Charger :
It produces a well regulated dc voltage suitable for charging the UPS batteries.
Figure 2.1 UPS Block Diagram
Inverter
Rectifier
Static By-Pass
Mechanical Transfer Switch
3 Phase
AC Input
1 Phase
AC Output
Battery
Battery Charger
