ABB MegaFlex UL S1 Series - Automatic Bypass Function

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MegaFlex 1000 to 1600 UPS User Manual / REV-A
4.2.5 Automatic Bypass
In normal operation, the
Load
is supplied by
the
Inverter.
When the control system detects a fault in the
Inverter
, an overload condition or a short-
circuit condition, the
Automatic Bypass will
transfer the critical
Load to the Utility without
interruption.
When the
Inverter recovers, or the overload or
short
-circuit condition is corrected, the Load
will be automatically transferred back to the
Inverter.
Fig. 4.2.5-1 Block diagram Automatic Bypass
If the UPS is unable to return to normal mode following an automatic transfer to
Bypass mode
, an alarm
condition will be initiated.
In case of RPA Parallel System
Each unit has its own internal
Static Bypass.
These units are continuously exchanging information, enabling all of the internal Bypass circuits in a
n
RPA Parallel
System
to operate simultaneously.
If the
Inverter of a unit fails, its Bypass circuit remains available to the RPA Parallel System.
It is excluded only if the unit is separated from the common bus by opening its “
Q1 – External UPS Output
Circuit
Breaker”
.