Atlas Copco QAS 275-325, Instruction Manual

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Automatic Mains Failure (AMF)
operation
This application is only possible in combination with
the AUTO mode. If the SEMI-AUTO mode is
selected the AMF operation will NOT function!
The unit automatically starts the gen-set and switches
to generator supply at a mains failure after an
adjustable delay time.
– AMF no back synchronisation:
When the mains returns, the unit will switch back
to mains supply and cool down and stop the gen-
set. The switching back to mains supply is done
without back synchronisation when the adjusted
‘Mains OK delay’ has expired.
– AMF with back synchronisation:
When the mains returns, the unit will synchronise
the mains breaker to the busbar when the ‘Mains
OK delay’ has expired. Then the gen-set cools
down and stops.
Installation wirings
– The link between X25.10/X25.11 has to be
removed.
– Mains breaker feedback lines have to be wired to
X25.10/X25.11/X25.12.
– Mains breaker control lines have to be wired to
X25.13/X25.14/X25.15/X25.16. These terminals
are voltage free contacts. The power for the MB
has to be supplied by the customer (24 Vdc/
230 Vac) (max. contact rating K11, K12 = 250 V/
16 A).
– The Mains sensing lines L1/L2/L3/N have to be
wired to terminals X25.3/X25.4/X25.5/X25.6.
– Make sure the connections between X25.33 &
X25.3; X25.34 & X25.4; X25.35 & X25.5;
X25.36 & X25.6 are removed.
– If back synchronisation is enabled, all settings for
paralleling set up (see “Paralleling”) must be
verified also.
Peak Shaving (PS) operation
This application is normally used in combination with
the AUTO mode. Installation with the Mains.
The generator will start up when the mains imported
power (measured through an optional Power
Transducer = PT) exceeds a defined level. The
generator will synchronise with the bus, and will take
load until the defined allowable mains imported
power level is reached.
When the mains imported power decreases below the
defined mains imported power level for a defined
time, the generator will unload and disconnect from
the bus. Then the generator will go into cool down.
Installation wirings
– The link between X25.10/X25.11 has to be
removed.
– Mains breaker feedback lines have to be wired to
X25.10/X25.11/X25.12.
– Mains breaker control lines have to be wired to
X25.13/X25.14/X25.15/X25.16. These terminals
are voltage free contacts. The power for the MB
has to be supplied by the customer (24 Vdc/
230 Vac) (max. contact rating K11, K12 = 250 V
/16 A).
– The Mains sensing lines L1/L2/L3/N have to be
wired to terminals X25.3/X25.4/X25.5/X25.6.
– Make sure the connections between X25.33 &
X25.3; X25.34 & X25.4; X25.35 & X25.5;
X25.36 & X25.6 are removed.
– Power Transducer lines have to be wired to
X25.21 (input) and X25.22 (GND).
– Verify all settings for paralleling set up (see
“Paralleling”).