Fuji Electric Frenic lift, Reference Manual

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Main power
MC1
BATRY
MC2
73X
UPS/batteries power supply
DC link bus voltage Edc
FWD
Output Frequency
Undervoltage level
C03 : Battery/UPS operation speed
T1 T2 UPS/batteries operation allowable zone
ON
ON
ON
ON
ON
ON
ON
ON
E17 E17
0
L125 : UPS/batteries minimum operation level
Figure 1. Rescue operation sequence when DC link voltage > L125
As it can be observed Main supply is disconnected for any reason. At this point power supply is
changed from mains to batteries (or UPS) by means of MC1 and MC2. MC1 links mains supply to
the inverter, MC2 links batteries (or UPS) supply to the inverter. When MC2 is closed voltage
increases on DC Link. This voltage reaches L125 level. When inverter and controller are ready to
perform rescue operation it starts because DC link voltage level is over L125.
In figure 2, a rescue operation sequence when DC link voltage is below L125 level is shown.
Main power
MC1
BATRY
MC2
73X
UPS/batteries power supply
DC link bus voltage Edc
FWD
Output Frequency
Undervoltage level
C03 : Battery/UPS operation speed
T1 T2
UPS/batteries
operation
allowable zone
ON
ON
ON
ON
ON
ON
ON
ON
0
L125 : UPS/batteries minimum operation level
Alarm (LU)
ON
Figure 2. Rescue operation sequence when DC link voltage < L125
As it can be observed Main supply is disconnected for any reason. At this point power supply is
changed from mains to batteries (or UPS) by means of MC1 and MC2. When MC2 is closed voltage
increases on DC Link. This voltage reaches L125 level but after few minutes it goes below for any
reason. When inverter and controller are ready to perform rescue operation it cannot starts as DC
link voltage level is below L125. At this point inverter trips with LV alarm.
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