Fuji Electric Frenic lift, Reference Manual

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In figure 4, a stopping sequence with feedback contacts timing problem is shown.
Speed
0
High speed
Creep speed
Run command
(FWD, REV)
ON
SCC
Short-circuit contact
Open
SCCF
Stop speed(F25)
H67 L120 L56 L86
IGBT’s gate
Active
ON
EN1&EN2
ON
ON
L120
Inverter trips SCA.
ON
Alarm
Figure 4. Stopping sequence with feedback contact timing problem ( SCA alarm)
After time L121 has elapsed, because SCCF input (feedback) has not changed its status, SCA alarm
is issued.
In figure 5, a feedback problem during normal travel is shown.
Speed
0
High speed
Run command
(FWD, REV)
ON
SCC
Short-circuit contact
Open
SCCF
L120
IGBT’s gate
Active
ON
EN1&EN2
ON
ON
BRKS
ON
L82
Inverter trips SCA.
Alarm
ON
Feedback is lost.
Figure 5. Feedback problem during normal travel (
SCA
alarm).
As it can be observed, during motion no timer is considered, in other words, if feedback is lost
( SCCF input signal) inverter trips immediately with SCA alarm and output circuit is switched OFF.
This is in order to avoid as fast as possible any possible damage on the inverter’s output circuit.
In case that L120=1,
SCC will turn ON and OFF under certain conditions as it is explained above.
Figures 6, 7, 8 and 9 show the sequence in these cases.
Case 1: Inverter in alarm (
ALM output function ON)
Figure 6 shows the case when any alarm (except SCA ) is issued). As it can be observed, inverter
waits anyway the time L86 after IGBT’s gates are OFF. By means of this delay time, short circuit
contacts will be closed when brake is applied and no current is flowing.
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