Service manual

The DC/AC module, call also inverter, belongs to the output stage of the UPS, used to converse
the DC power from the DC-BUS into clean, stable AC output power.
When the mains line is within the tolerance range, the UPS use the mains input, at this time, the
AC/DC converter work; In case the mains line supply is output tolerance range, due to either the
voltage or the frequency, the UPS will stop the AC/DC converter working and start the DC/DC
module. In case the input mains supply interrupt suddenly, the controller can detect the
interruption in very short time, and in the interval before detecting the interruption, the output
power will be maintain by energy stored in the DC-BUS capacitor, there will never be appear
interruption on output.
The battery charger module converse the AC mains input into DC power for recharging the
Battery. Two type of charger can be available, one is for the standard model, and another is for
long backup time model that connects external battery.
The input EMI filter and output EMI filter are used for two purpose, the first one is to prevent the
UPS being interference by external electronic/magnetic noise which generated by the other
electronic system, the second is to prevent the noise generated inside the UPS system
interference other system.
The Power supply block generates DC power supply needed by operation of the circuit of the UPS
itself.
The internal Bypass provides an alternative path in case the power conversion stage become out
of order, to maintain the continuity of output supply.
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